The present invention concerns immunogenic compositions enabling inducing a cross-reactive immune response in a subject against rhinovirus antigens. Human rhinovirus (HRV) infections are the most frequent cause of the common cold and are highly associated with exacerbations of asthma and chronic obstructive pulmonary disease (COPD) in individuals at risk. Despite the great disease burden and healthcare costs therefore attributable to HRV infections, there is currently neither a vaccine nor specific anti-viral therapy available. The requirements for immunity to HRV are poorly understood. Both experimental and natural infections do induce antibodies which provide some protection against r e infection with the same HRVtype. There are however greater than loo serotypes of HRV, a number which is likely to increase further with the identification and characterization of new serotypes. Currently the main efforts to develop a candidate vaccine against HRV are focusing on the identification of antigens that induce a broad neutralizing antibody response. This approach is described in the international application WO 2011/050384, whereby it is shown that antibodies raised against a recombinant rhinovirus capsid protein, VPi, show cross-protection against distantly related HRV strains. Another study (Katpally et al. (2009) J.Virol. 83:7040-7048) shows that antibodies directed to the buried N-terminus of the rhinovirus capsid protein, VP4, exhibit cross-serotypic neutralization. However, there is no certainty that a vaccine strategy based only on generating neutralizing antibodies could provide a sufficient and broad protection to prevent the frequent HRVinfections which occur throughout life. There is therefore an important need to develop alternative vaccine strategies that could be more successful. Vaccination strategies based on inducing T cell responses to conserved antigens have been explored in a number of infectious diseases, including respiratory virus infections. The advantage of such a strategy lies in the ability of T cells to recognize internal regions of the virus, which are frequently more conserved than surface exposed antibody epitopes. T cells are therefore potentially cross-reactive against different virus strains, as has been shown with influenza viruses (Lee et al. (2008) J . Clin. Invest. 118:3478-3490; Richards et al. (2010) J . Immunol. 185:4998-5002) for which surface antigenic variability is a major barrier to effective vaccine design. For HRVs, naturally occurring memory T cells have been shown to be cross-serotype responsive (Gern et al. (1997) J . Infect. Dis. 175 :1108-1114; Wimalasundera et al. (1997) J . Infect. Dis. 176 :755-759) and immunization of mice with peptides from VPi and VP3 capsid proteins of HRV has been suggested to be capable of inducing cross-serotype reactive T cells (Hastings et al. (1993) Eur. J . Immunol. 2 3 :2300-2305). However, it has not been shown that a T cell mediated immune response against HRVis protective against rhinovirus infection. The inventors have now featured new immunogenic compositions that are able to induce a broad cross-reactive cellular immune response among rhinoviruses, and which have been shown to also accelerate rhinovirus clearance in rhinovirus infected subjects. Based on linear sequence conservation among HRVs, the inventors identified antigens which were able to induce antigen-specific, cross-reactive, type I-orientated T cell responses and enhanced neutralizing antibody responses following infection in mice. Said antigens correspond to conserved domains in the HRV Pi polyprotein and the HRV RNA polymerase. Specifically, the inventors identified as a particularly useful antigen: - an isolated peptide comprising, or consisting of, an amino acid sequence which is at least 90% identical to the VP4 amino acid sequence of a rhinovirus; - a fusion peptide comprising an amino acid sequence which is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, covalently linked to another conserved amino acid sequence of the "large" polyprotein of the rhinovirus, including in particular all or part of the VP2 amino acid sequence and/or conserved domains of the RNA polymerase; or - an isolated peptide comprising, or consisting of, an amino acid sequence of at least 100 amino acids which is at least 90% identical to an amino acid sequence located in the last 363 C-terminal amino acids of the RNApolymerase of a rhinovirus. In particular, administering to mice a peptide comprising the HRV16 VP4 peptide, more particularly a peptide consisting of the HRV16 VPo polyprotein, or a peptide, the amino acid sequence of which is located within the last 363 C-terminal amino acids of the HRV16 RNA polymerase, enabled inducing a cross-reactive immune response against HRV16, but also against other HRVserotypes, such as HRV14, HRViB or HRV29. The present invention therefore concerns an immunogenic composition comprising: a) an isolated peptide or a fusion peptide as described above comprising an amino acid sequence which is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, or an isolated polynucleotide comprising a nucleic acid sequence encoding said peptide, placed under the control of the elements necessary for its expression in a mammalian cell; and/or b) an isolated peptide comprising an amino acid sequence of at least 100 amino acids which is at least 90% identical to an amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus, or an isolated polynucleotide comprising a nucleic acid sequence encoding said peptide, placed under the control of the elements necessary for its expression in a mammalian cell; and c) a Thi adjuvant when said immunogenic composition comprises one or more of said isolated peptides or fusion peptides. The present invention also concerns an immunogenic composition as defined above for use in a mammal to induce a specific cross-reactive cell-mediated immune response against at least two serotypes of rhinoviruses. The present invention is further drawn to an immunogenic composition as defined above for use in a mammal to induce a specific neutralizing antibody response when infected by a rhinovirus. The present invention also concerns an immunogenic composition as defined above for use in a mammal to shorten or prevent an infection by a rhinovirus, and/or to reduce or prevent the clinical symptoms associated with the infection. Therefore, the immunogenic composition as defined above can be used as a vaccine to protect against rhinovirus infection. Detailed description of the invention Rhinoviruses In the context of the invention, the term "rhinovirus" or "HRV" (Human rhinovirus) refers to any member of the family Picornaviridae genus Enterovirus according to the recent taxonomy. There are 3 different groups of rhinoviruses: Human rhinovirus A (HRV-A) also called type A rhinovirus, Human rhinovirus B (HRV-B) also called type Brhinovirus and Human rhinovirus C(HRV-C) also called type Crhinovirus. HRVs are further classified according to their serotype, of which more than 100 have been reported until now. As used herein, the term "serotype" refers to a subdivision within a group of rhinoviruses and relies on the VPi gene sequence of the rhinovirus. A given serotype of rhinovirus may contain one or several strains that are distinguished by secondary characteristics. HRVs have been classified according to several other parameters, including receptor specificity, antiviral susceptibility and nucleotide sequence homologies. The HRV-Aspecies includes in particular the following serotypes: HRViA, HRViB, HRV2, HRV7, HRV8, HRV9, HRV10, HRV11, HRV12, HRV13, HRV15, HRV16, HRV18, HRV19, HRV20, HRV21, HRV22, HRV23, HRV24, HRV25, HRV28, HRV29, HRV30, HRV31, HRV32, HRV33, HRV34, HRV36, HRV38, HRV39, HRV40, HRV41, HRV43, HRV44, HRV45, HRV46, HRV47, HRV49, HRV50, HRV51, HRV53, HRV54, HRV55, HRV56, HRV57, HRV58, HRV59, HRV60, HRV61, HRV62, HRV63, HRV64, HRV65, HRV66, HRV67, HRV68, HRV71, HRV73, HRV74, HRV75, HRV76, HRV77, HRV78, HRV80, HRV81, HRV82, HRV85, HRV88, HRV89, HRV90, HRV94, HRV95, HRV96, HRV98, HRV100, HRV101, HRV102 and HRV103; the HRV-B species includes in particular the following serotypes: HRV3, HRV4, HRV5, HRV6, HRV14, HRV17, HRV26, HRV27, HRV35, HRV37, HRV42, HRV48, HRV52, HRV69, HRV70, HRV72, HRV79, HRV83, HRV84, HRV86, HRV91, HRV92, HRV93, HRV97 and HRV99; and the HRV-C species includes in particular the following serotypes: HRVC-i, HRVC-2, HRVC-3, HRVC-4, HRVC-5, HRVC-6, HRVC-7, HRVC-8, HRVC-9, HRVC-10, HRVC-11, HRVC-12, HRVC-13, HRVC-14, HRVC-15, HRVC-16, HRVC-17, HRVC-18, HRVC-19, HRVC-20, HRVC-21, HRVC-22, HRVC-23, HRVC-24, HRVC-25, HRVC-26, HRVC-27, HRVC-28, HRVC-29, HRVC-30, HRVC-31, HRVC-32, HRVC-33, HRVC-34, HRVC-35, HRVC-36, HRVC-37, HRVC-38, HRVC-39, HRVC-40, HRVC-41, HRVC-42, HRVC-43, HRVC-44, HRVC-45, HRVC-46, HRVC-47, HRVC-48 and HRVC-49. HRV serotypes may also be grouped according to receptor usage into minor-group viruses and major-group viruses. Minor-group viruses, such as HRV2, use the low-density lipoprotein receptor family as receptor. They are acid labile and have an absolute dependence on low pH for uncoating. Major-group viruses, such as HRV14 and HRV16, use intercellular adhesion molecule 1 (ICAM-i) as receptor. They are also generally acid labile but, unlike the minorgroup viruses, do not have an absolute dependence on low pH for uncoating. As well-known from the skilled person, minor-group HRVs include 11 serotypes, including HRViA, HRViB, HRV2, HRV23, HRV25, HRV29, HRV30, HRV31, HRV44, HRV47, HRV49 and HRV62, and major-group HRVs include the remaining serotypes. HRVs have a 25 nm capsid of icosahedral symmetry, made up of 60 copies of each of four virus-coded proteins (VPi, VP2, VP3 and VP4) and enclosing a single-stranded RNA genome of approximately 7,500 nucleotides. The RNA is of positive polarity, is polyadenylated at its 3' terminus and is covalently bound at its 5' terminal end to a small protein, VPg. The primary translational product of this RNA is a single, "large" polyprotein, divided into three smaller polyproteins called, Pi, P2 and P3, which are subsequently processed by proteolytic cleavage to yield the mature virus proteins. The Pi polyprotein is composed of four peptides (lA or VP4, iB or VP2, iC or VP3, and iD or VPi), the P2 polyprotein is composed of three peptides (2A, 2B and 2C) and the P3 polyprotein is composed of four peptides (3A, 3B, 3C and 3D, which corresponds to the RNA polymerase). The Pi polyprotein is the precursor that gives rise to the four structural proteins of the nucleocapsid. The Pi polyprotein is first cleaved to produce the VPo polyprotein, which contains the amino acid sequence of VP4 and VP2 peptides, the VP3 peptide and the VPi peptide. The VPo polyprotein is then cleaved into the VP4 peptide and the VP2 peptide once the virus has assembled. In the context of the invention, the term "VPo polyprotein", "VPo peptide" or "peptide lAB" therefore refers to the protein precursor derived from the HRV Pi polyprotein and which consists of the amino acid sequence of VP4 and VP2 peptides. VPo polyprotein is typically about 330 amino acids long. As known from the skilled person, the amino acid sequence of the VPo polyprotein may slightly vary according to the HRV serotype or group. In the context of the invention the term "about" as used herein when referring to a measurable value, such as an amount, duration or a number, such as the number of amino acids in an amino acid sequence, is meant to encompass variations of ± 5%. In the context of the invention the term "a" or "an" entity refers to one or more of that entity. For example "a polynucleotide", "an isolated peptide", "a fusion peptide", "an isolated polynucleotide" is understood to represent respectively at least one or more "polynucleotide", at least one or more "isolated peptide", at least one or more "fusion peptide", at least one or more "isolated polynucleotide". In the context of the invention, the terms "comprising", "having", "including" and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Additionally, the term "comprising" encompasses "consisting" (e.g., a composition "comprising" X may consist exclusively of X or may include something additional, e.g., X+Y). In an embodiment, the amino acid sequence of the VPo polyprotein is the amino acid sequence of the VPo polyprotein of the HRV16 serotype, which consists typically in the sequence: MGAQVSRQNVGTHSTQNMVSNGSSLNYFNINYFKDAASSGASRLDFSQDPSKFTDPVKD VLEKGIPTLQSPSVEACGYSDRIIQITRGDSTITSQDVANAWGYGVWPHYLTPQDATAID KPTQPDTSSNRFYTLDSKMWNSTSKGWWWKLPDALKDMGIFGENMFYHFLGRSGYTV HVQCNASKFHQGTLLWMIPEHQLATVNKGNVNAGYKYTHPGEAGREVGTQVENEKQP SDDNWLNFDGTLLGNLLIFPHQFINLRSNNSATLIVPYVNAVPMDSMVRHNNWSLVIIP VCQLQSNNISNIVPITVSISPMCAEFSGARAKTW (SEQ ID NO: 6). In another embodiment, the amino acid sequence of the VPo polyprotein is the amino acid sequence of the VPo polyprotein of the HRV14 serotype, which consists typically in the sequence: MGAQVSTQKSGSHENQNILTNGSNQTFTVINYYKDAASTSSAGQSLSMDPSKFTEPVKDL MLKGAPALNSPNVEACGYSDRVQQITLGNSTITTQEAANAWCYAEWPEYLPDVDASDV NKTSKPDTSVCRI^LDSKTWTTGSKGWCWKLPDALKDMGVFGQNMFFHSLGRSGYTV HVQCNATKFHSGCLLVWIPEHQLASHEGGNVSVKYTFTHPGERGIDLSSANEVGGPVK DVIYNMNGTLLGNLLIFPHQFINLRTNNTATIVIPYINSVPIDSMTRHNNVSLMVIPIAPLT VPTGATPSLPITVTIAPMCTEFSGIRSKSIV(SEQ ID NO: 8). The corresponding VPo polyprotein amino acid sequence from other HRV serotypes may easily be determined by the skilled person, typically by sequence alignment, such as global pairwise alignment. In the context of the invention, the term "VP4 peptide" or "peptide lA" refers to an HRV protein capsid, derived from the VPo polyprotein precursor, which lies at the interface between the capsid and the interior genomic RNA. VP4 peptide is about 68 or 69 amino acids long and is generally situated from amino acid 1to amino acid 69 of the VPo polyprotein. As known from the skilled person, the length of the amino acid sequence of the VP4 peptide may slightly vary according to the HRV serotype. According to an embodiment, the amino acid sequence of the VP4 peptide is the amino acid sequence of the VP4 peptide of the HRV16 serotype, which consists typically in the sequence: MGAQVSRQNVGTHSTQNMVSNGSSLNYFNINYFKDAASSGASRLDFSQDPSKFTDPVKD VLEKGIPTLQ (SEQ ID NO: 1). According to another embodiment, the amino acid sequence of the VP4 peptide is the amino acid sequence of the VP4 peptide of the HRV14 serotype, which consists typically in the sequence: MGAQVSTQKSGSHENQNILTNGSNQTFTVINYYKDAASTSSAGQSLSMDPSKFTEPVKDL MLKGAPALN (SEQ ID NO: 2). The corresponding VP4 peptide sequence from other HRV serotypes may easily be determined by the skilled person, typically by sequence alignment, such as global pairwise alignment. In the context of the invention, the term "VP2 peptide" or "peptide lB" refers to an HRV protein capsid, derived from the VPo polyprotein precursor, which lies at the external side of the capsid. VP2 peptide is about 270 amino acids long. Generally, the VP2 peptide is situated between amino acids 70 and 339 of the VPo polyprotein. As known from the skilled person, the length of the amino acid sequence of the VP2 peptide may slightly vary according to the HRVserotype. According to an embodiment, the amino acid sequence of the VP2 peptide is the amino acid sequence of the VP2 peptide of the HRV16 serotype, which consists typically in the sequence: SPSVEACGYSDRIIQITRGDSTITSQDVANAWGYGVWPHYLTPQDATAIDKPTQPDTSSN RFYTLDSKMWNSTSKGWWWKLPDALKDMGIFGENMFTHFLGRSGYTVHVQCNASKFH QGTLLVVMIPEHQIATVNKGNVNAGYKYTHPGEAGREVGTQVENEKQPSDDNWLNFD GTLLGNLLIFPHQFINLRSNNSATLIVPYVNAVPMDSMVRHNNWSLVIIPVCQLQSNNIS NIVPITVSISPMCAEFSGARAKTW (SEQ ID NO: 3). According to another embodiment, the amino acid sequence of the VP2 peptide is the amino acid sequence of VP2 peptide of the HRV14 serotype, which consists typically in the sequence: SPNVEACGYSDRVQQITLGNSTITTQEAANAWCYAEWPEYLPDVDASDVNKTSKPDTSV CRFYTLDSKTWTTGSKGWCWKLPDALKDMGVFGQNMFFHSLGRSGYTVHVQCNATKF HSGCLLVWIPEHQLASHEGGNVSVKYTFTHPGERGIDLSSANEVGGPVKDVIYNMNGTL LGNLLIFPHQFINLRTNNTATIVIPYINSVPIDSMTRHNNVSLMVIPIAPLTVPTGATPSLPI TVTIAPMCTEFSGIRSKSIV (SEQ ID NO: 4). The corresponding VP2 peptide sequence from other HRV serotypes may easily be determined by the skilled person, typically by sequence alignment, such as global pairwise alignment. In the context of the invention, the term "RNA polymerase" or "peptide 3D" refers to the HRV RNA-dependent RNA polymerase, located at the carboxy-terminal end of the precursor "large" polyprotein, within the P3 protein, and which is the core enzyme utilized for both negative-strand RNA synthesis and reiterative synthesis of multiple copies of positive strand RNA for packaging into progeny virions. HRV RNA polymerase is typically described in Appleby et al. (2005) J . Virol. 79 :277-288. HRV RNA polymerase is typically about 460 amino acids long. As known from the skilled person, the length of the amino acid sequence of the RNA polymerase may slightly vary according to the HRVserotype. According to an embodiment, the amino acid sequence of the RNA polymerase is the amino acid sequence of the RNA polymerase of the HRV16 serotype, which consists typically in the sequence: GQIQISKHVKDVGLPSIHTPTKTKLQPSVFYDIFPGSKEPAVLTEKDPRLKVDFDSALFSKY KGNTECSLNEHIQVAVAHYSAQLATLDIDPQPIAMEDSVFGMDGLEALDLNTSAGYPYVT LGIKKKDLINNKTKDISKLKLALDKYDVDLPMITFLKDELRKKDKIAAGKTRVIEASSIND TILFRTVYGNLFSKFHLNPGWTGCAVGCDPETFWSKIPLMLDGDCIMAFDYTNYDGSIH PIWFKALGMVLDNLSFNPTLINRLCNSKHIFKSTYYEVEGGVPSGCSGTSIFNSMINNIIIR TLVLDAYKHIDLDKLKIIAYGDDVIFSYKYKLDMEAIAKEGQKYGLTITPADKSSEFKELDY GNVTFLKRGFRQDDKYKFLIHPTFPVEEIYESIRWTKKPSQMQEHVLSLCHLMWHNGPE IYKDFETKIRSVSAGRALYIPPYELLRHEWYEKF(SEQ ID NO: 15). According to another embodiment, the amino acid sequence of the RNA polymerase is the amino acid sequence of the RNA polymerase of the HRV14 serotype, which consists typically in the sequence: GQVIARHKVREFNINPVNTPTKSKLHPSVFYDVFPGDKEPAVLSDNDPRLEVKLTESLFSK YKGNVNTEPTENMLVAVDHYAGQLLSLDIPTSELTLKEALYGVDGLEPIDITTSAGFPYVS LGIKKRDILNKETQDTEKMKFYLDKYGIDLPLVTYIKDELRSVDKVRLGKSRLIEASSLND SVNMRMKLGNLYKAFHQNPGVLTGSAVGCDPDVFWSVIPCLMDGHLMAFDYSNFDASL SPVWFVCLEKVLTKLGFAGSSLIQSICNTHHIFRDEIYWEGGMPSGCSGTSIFNSMINNIII RTLILDAYKGIDLDKLKILAYGDDLIVSYPYELDPQVLATLGKNYGLTITPPDKSETFTKMT WENLTFLKRYFKPDQQFPFLVHPVMPMKDIHESIRWTKDPKNTQDHVRSLCMLAWHS GEKEYNEFIQKIRTTDIGKCLILPEYSVLRRRWLDLF (SEQ ID NO: 16). The corresponding RNA polymerase sequence from other HRV serotypes may easily be determined by the skilled person, typically by sequence alignment, such as global pairwise alignment. In the context of the invention, the term "C-terminal domain of the RNA polymerase of a rhinovirus" refers to the C-terminal end of the HRV RNA polymerase as defined above, in particular to the last 363 C-terminal amino acids of the HRV RNA polymerase as defined above. As known from the skilled person, the length of the amino acid sequence of the C-terminal domain of the HRV RNA polymerase may slightly vary according to the HRV serotype. According to an embodiment, the amino acid sequence of the C-terminal domain of the RNA polymerase is the amino acid sequence of the C-terminal domain of the RNA polymerase of the HRV16 serotype, which consists typically in the sequence: EDSVFGMDGLEALDLNTSAGYPYVTLGIKKKDLINNKTKDISKLKLALDKYDVDLPMITFL KDELRKKDKIAAGKTRVIEASSINDTILFRTWGNLFSKFHLNPGVVTGCAVGCDPETFWS KIPLMLDGDCIMAFDYTNYDGSIHPIWFKALGMVLDNLSFNPTLINRLCNSKHIFKSTYYE VEGGVPSGCSGTSIFNSMINNIIIRTLVLDAYKHIDLDKLKIIAYGDDVIFSYKYKLDMEAIA KEGQKYGLTITPADKSSEFKELDYGNVTFLKRGFRQDDKYKFLIHPTFPVEEIYESIRWTK KPSQMQEHVLSLCHLMWHNGPEIYKDFETKIRSVSAGRALYIPPYELLRHEWYEKF (SEQ ID NO: 13). According to another embodiment, the amino acid sequence of the C-terminal domain of the RNA polymerase is the amino acid sequence of the C-terminal domain of the RNApolymerase of the HRV14 serotype, which consists typically in the sequence: KEALYGVDGLEPIDITTSAGFPYVSLGIKKRDILNKETQDTEKMKFYLDKYGIDLPLVTYIK DELRSVDKVRLGKSRLIEASSLNDSVNMRMKLGNLYKAFHQNPGVLTGSAVGCDPDVF WSVIPCLMDGHLMAFDYSNFDASLSPVWFVCLEKVLTKLGFAGSSLIQSICNTHHIFRDEI YWEGGMPSGCSGTSIFNSMINNIIIRTLILDAYKGIDLDKLKILAYGDDLIVSYPYELDPQV LATLGKNYGLTITPPDKSETFTKMTWENLTFLKRYFKPDQQFPFLVHPVMPMKDIHESIR WTKDPKNTQDHVRSLCMLAWHSGEKEYNEFIQKIRTTDIGKCLILPEYSVLRRRWLDLF (SEQ ID NO: 14). The corresponding RNA polymerase C-terminal domain sequence from other HRV serotypes may easily be determined by the skilled person, typically by sequence alignment, such as global pairwise alignment. Peptides Based on linear sequence conservation among HRVs, the present inventors identified antigens which were able to induce a cross-reactive immune response against different serotypes of rhinoviruses and even more unexpectedly against rhinoviruses belonging to different groups of rhinoviruses (cross-serotype and/or inter-group reactive immune response). Said antigens correspond to conserved domains in the HRV VPo polyprotein and the HRV RNA polymerase, as defined in the section "Rhinoviruses" herein above. In particular, the inventors demonstrated that administering to mice a peptide comprising the HRV16 VP4 peptide, more particularly a peptide consisting of the HRV16 VPo polyprotein, enabled inducing a cross-reactive immune response against HRV16, but also against other HRVserotypes, such as HRV14, HRViB or HRV29. Specifically, the inventors identified as a particularly useful antigen: - an isolated peptide a) comprising, or consisting of, an amino acid sequence which is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above, or - a fusion peptide comprising an amino acid sequence which is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above, covalently linked to another conserved amino acid sequence located in the "large" polyprotein, as defined in the section "Rhinoviruses" herein above, of a rhinovirus. The inventors also identified as another particularly useful antigen, an isolated peptide b) comprising, or consisting of, an amino acid sequence of at least 100 amino acids which is at least 90% identical to an amino acid sequence located in the last 363 Cterminal amino acids of the RNA polymerase of a rhinovirus, as defined in the section "Rhinoviruses" herein above. By "an amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase" is meant an amino acid sequence which consists of a chain of contiguous amino acids found in the region defined by the last 363 C-terminal amino acids of the RNA polymerase, i.e a fragment of said region. As used herein, the term "isolated" means removed from the natural environment, i.e. from rhinoviruses or cells infected by a rhinovirus. Usually, it refers to a peptide, a fusion peptide or a nucleic acid substantially free of cellular material, bacterial material, viral material, or culture medium when produced by recombinant DNA techniques, or chemical precursors, or other chemicals when chemically synthesized. The term "substantially" encompasses "completely" or "nearly" (e.g., a composition which is "substantially free" from Ymay be completely free from Yor may contain residual amount of Y). According to the invention, a polypeptide, peptide or fusion peptide consists of at least about 60 amino acids, in particular at least about 68 amino acids, at least 69 amino acids, at least 120 amino acids, at least 140 amino acids, at least 160 amino acids, at least 180 amino acids, at least 200 amino acids, at least 220 amino acids, at least 240 amino acids, at least 260 amino acids, at least 280 amino acids, at least 300 amino acids, at least 320 amino acids, at least 340 amino acids, or even at least 370 amino acids. According to the invention, a polypeptide, peptide or fusion peptide consists of less than 500 amino acids, in particular of less than 450, less than 400, or even less than 380 amino acids. Accordingly, the size of a polypeptide, peptide or fusion peptide is typically between 60 and 500 amino acids long, in particular between 68 and 500 amino acids long, more particularly between 100 and 500 amino acids long, still particularly between 100 and 400 amino acids long, the bounds being included. As used herein, the term "amino acid" is understood to include the 20 naturally occurring amino acids. As used herein, a first amino acid sequence is at least x% identical to a second amino acid sequence means that x% represents the number of amino acids in the first sequence which are identical to their matched amino acids of the second sequence when both sequences are optimally aligned, relative to the total length of the second amino acid sequence. Both sequences are optimally aligned when x is maximum. The alignment and the determination of the percentage of identity may be carried out manually or automatically using for instance the Needleman and Wunsch algorithm, described in Needleman and Wunsch (1970) J . Mol Biol. 48:443-453, with for example the following parameters for polypeptide sequence comparison: comparison matrix: BLOSSUM62 from Henikoff and Henikoff (1992) Proc. Natl. Acad. Sci. USA. 89:10915-10919, gap penalty: 8 and gap length penalty: 2; and the following parameters for polynucleotide sequence comparison: comparison matrix: matches = +10, mismatch = o; gap penalty: 50 and gap length penalty: 3. A program useful with the above parameters is publicly available as the "gap" program from Genetics Computer Group, Madison W The aforementioned parameters are the default parameters respectively for peptide comparisons (along with no penalty for end gaps) and for nucleic acid comparisons. In particular, the isolated peptide a) of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 90% identical, at least 95% identical, at least 97% identical, at least 98% identical, at least 99% identical or even 100% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above. For instance any VP4 amino acid sequence of a rhinovirus strain which is at least 90% identical to the VP4 peptide of the HRV16 serotype (SEQ ID NO: 1) or of the HRV14 serotype (SEQ ID NO: 2) is suitable for the purpose of the invention. The isolated peptide b) of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence of at least 100 amino acids, for instance at least 105, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 320, 330, 340 or 350 amino acids, in particular at least 360 amino acids which is at least 90% identical to an amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus as defined in the section "Rhinoviruses" herein above. More particularly, the isolated peptide b) of the invention comprises, or consists of an amino acid sequence of at least 100 amino acids which is at least 95% identical, at least 97% identical, at least 98% identical, at least 99%, or even 100% identical to the RNA polymerase amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above. For instance any amino acid sequence of at least 100 amino acids located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of the HRV16 serotype (SEQ ID NO: 13) or of the HRV14 serotype (SEQ ID NO: 14) is suitable for the purpose of the invention. In some particular instances, even if not preferred, a natural amino acid may be substituted by an amino acid modified post-translationally in vivo, including for example hydroxyproline, phosphoserine and phosphothreonine; by unusual amino acids including, but not limited to, 2-aminoadipic acid, hydroxylysine, isodesmosine, nor-valine, norleucine and ornithine or by another chemically modified amino acid. Peptides and fusion peptides of the invention may be synthesized by any method well-known from the skilled person. Such methods include conventional chemical synthesis (in solid phase or in liquid homogenous phase), enzymatic synthesis from constitutive amino acids or derivatives thereof, as well as biological production methods by recombinant technology. Chemical synthesis can be particularly advantageous because it allows high purity, antigenic specificity, the absence of undesired by-products and ease of production. The peptide obtained by such methods can then optionally be purified using any method known from the skilled person. The method of production can also include one or more steps of chemical or enzymatic modification of the peptide in order to improve its stability or its bioavailability. Chemical synthesis includes Merrifield type synthesis and Fmoc solid phase peptide synthesis methods (see for example "Fmoc solid Phase peptide synthesis, a practical approach", published by W.C. Chan et P. D. White, Oxford University Press, 2000). The peptide or fusion peptide of the invention can also be obtained using a biological production process with a recombinant host cell. In such a process, a vector containing a nucleic acid encoding the peptide or fusion peptide of the invention, in particular a nucleic acid as defined in the section "Nucleic acids" herein below, is transferred into a host cell, which is cultured in conditions enabling expression of the corresponding peptide or fusion peptide. The peptide or fusion peptide thereby produced can then be recovered and purified. Methods of purification that can be used are well-known from the skilled person. The obtained recombinant peptide or fusion peptide can be purified from lysates and cell extracts, from the culture medium supernatant, by methods used individually or in combination, such as fractionation, chromatographic methods, immunoaffinity methods using specific mono- or polyclonal antibodies, etc... Fusion peptides In the context of the invention, the term "fusion peptide" refers to a peptide composed of all or part of the amino acid sequence of at least two or more individual peptide units of a rhinovirus linked together via a covalent linkage, e.g. via peptide (amide) bonds. More specifically, the fusion peptide included in the immunogenic composition according to the invention refers to the VP4 amino acid sequence of a rhinovirus, or an amino acid sequence that is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, linked by a covalent linkage to another conserved amino sequence present in the "large" polyprotein of a rhinovirus. Even if, among all the rhinovirus peptides (VP4, VPi, VP2, VP3, peptides 2A, 2B, 2C, 3A, 3B, 3C, 3D), the VP4 amino acid sequence is considered as being the most conserved amino acid sequence among the rhinoviruses, the inventors have found that when the VP4 amino acid sequence is covalently linked to an amino acid sequence located in the VP2 amino sequence of a rhinovirus and/or an amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase, which are domains that the inventors have identified as being conserved among rhinoviruses, such fusion peptides associated with a Thi adjuvant are able to induce a cross-reactive immune response against different serotypes of rhinoviruses. More unexpectedly, a cross-reactive immune cell response against rhinoviruses belonging to different species of rhinoviruses has been observed. Furthermore the inventors have shown that such fusion peptides can rapidly induce virus clearance in rhinovirus-infected mice. In a preferred embodiment, the isolated peptide a) of the immunogenic composition according to the invention is a fusion peptide which comprises, or consists of, an amino acid sequence that is at least 90% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above, linked, by a covalent linkage, to another amino acid sequence which is at least 90% identical to an amino acid sequence located in the VP2 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above. The whole amino acid sequence of VP2 is about 270 amino acids long. The amino acid sequence located in the VP2 amino acid sequence which is covalently linked to the VP4 amino acid sequence can be all or part of the VP2 amino acid sequence. When it is only a part of the VP2 amino acid sequence, it can be any portion of the VP2 amino acid sequence. It can be the N-terminal part, the C-terminal part or the central part of the VP2 amino acid sequence. Preferably, the fusion peptide comprises all or part of the most conserved domains of the VP2 amino acid sequence which are located between amino acids 70 and 191 and between amino acids 243 and 297 in the VPo polyprotein amino acid sequence. In view of the foregoing, the size of the VP2 amino acid sequence that is covalently linked to the VP4 amino acid sequence is at least 30, at least 35, at least 40, at least 50, at least 60, at least 70, at least 100, at least 150, at least 200, at least 250 consecutive amino acids long. The VP4 and VP2 amino acid sequences that are linked together are not necessary contiguous amino acid sequences in the VPo polyprotein. Preferably the C-terminal end of the VP4 amino acid sequence is covalently linked by a peptide bond to the N-terminal end of the VP2 amino acid sequence. The different domains of the fusion peptide of the immunogenic composition according to the invention are generally directly coupled to one another. Optionally, in case it facilitates the production process of the fusion peptide, the different domains can be coupled via a linker that may be an amino acid, a peptide of appropriate length, or a different molecule providing the desired features. The skilled person knows how to design appropriate linker molecules, in particular linker peptides based on his common knowledge. For example, peptide linkers can be chosen from the LIP (Loops in Proteins) database (Michalsky etal. (2003) Prot. Eng. 56 :979-985). According to an embodiment, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 90% identical, at least 95% identical, in particular at least 96% identical, 97%, 98%, 99% or 100% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above, linked, by a covalent linkage, in particular a peptide bond, to another amino acid sequence which is at least 90% identical, in particular at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence located in the VP2 amino acid sequence of the same or a different rhinovirus, as defined in the section "Rhinoviruses" herein above. Preferably, the C-terminal end of the VP4 amino acid sequence is covalently linked by a peptide bond to the N-terminal end of the VP2 amino acid sequence. For instance, a fusion peptide comprising any VP4 amino acid sequence of a rhinovirus strain which is at least 90% identical to the VP4 peptide of the HRV16 serotype (SEQ ID NO: 1) linked to any amino acid sequence located in the VP2 amino acid sequence of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence in the VP2 amino acid sequence of the HRV16 serotype rhinovirus (SEQ ID NO: 3) is suitable for the purpose of the invention. Similarly, a fusion peptide comprising any VP4 amino acid sequence of a rhinovirus strain which is at least 90% identical to the VP4 peptide of the HRV14 serotype (SEQ ID NO: 2) linked to any amino acid sequence located in the VP2 amino acid sequence of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence in the VP2 amino acid sequence of the HRV14 serotype rhinovirus (SEQ ID NO: 4) is suitable for the purpose of the invention. In another embodiment, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 80% identical, in particular at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to an amino acid sequence located in the VPo polyprotein of a rhinovirus, as defined in the section "Rhinoviruses" herein above. In particular, said amino acid sequence located in the VPo polyprotein is an amino acid sequence constituted of from 120 to 370 consecutive amino acids, more particularly from 140 to 340 amino acids, from 160 to 320 amino acids, from 180 to 300 amino acids, from 200 to 280 amino acids or from 220 to 260 amino acids. Preferably the amino acid sequence located in the VPo polyprotein comprises the whole VP4 amino acid sequence. As a matter of example, the present inventors demonstrated that a fusion peptide comprising the first 135 N-terminal amino acids of the VPo polyprotein or the whole VPo polyprotein of a rhinovirus induces a cross-reactive cell immune response against different serotypes of rhinoviruses, and can also rapidly induces virus clearance in rhinovirus-infected mice. Accordingly, in a particular embodiment, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence consisting of the first 135 N-terminal amino acids of the VPo polyprotein of a rhinovirus, as defined in the section "Rhinoviruses" herein above. More particularly, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 80% identical, more particularly at least 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence consisting of the first 135 N-terminal amino acids of the VPo polyprotein of HRV16, said first 135 N-terminal amino acids consisting typically of the sequence MGAQVSRQNVGTHSTQNMVSNGSSLNYFNINYFKDAASSGASRLDFSQDPSKFTDPVKD VLEKGIPTLQSPSVEACGYSDRIIQITRGDSTITSQDVANAWGYGVWPHYLTPQDATAID KPTQPDTSSNRFYTL (SEQ ID NO: 5). Alternatively, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 80% identical, more particularly at least 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence consisting of the first 135 N-terminal amino acids of the VPo polyprotein of HRV14, said first 135 N-terminal amino acids consisting typically of the sequence MGAQVSTQKSGSHENQNILTNGSNQTFTVINYYKDAASTSSAGQSLSMDPSKFTEPVKDL MLKGAPALNSPNVEACGYSDRVQQITLGNSTITTQEAANAWCYAEWPEYLPDVDASDV NKTSKPDTSVCRFYTL (SEQ ID NO: 7). Still particularly, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 80% identical, more particularly at least 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the whole amino acid sequence of the VPo polyprotein of HRV16 or of the VPo polyprotein of HRV14, as defined in the section "Rhinoviruses" herein above. Aiming at reducing the number of antigens, the present inventors also designed fusion peptides between the conserved regions situated in the VPo polyprotein and the ones situated in the RNApolymerase, which retained a global antigen size easy to express. Accordingly, in a particular embodiment, the fusion peptide of the immunogenic composition according to the invention comprises, or consists, of (i) an amino acid sequence that is at least 90% identical, more particularly at least 95%, 96%, 97%, 98%, 99% or 100% identical to the VP4 amino acid sequence of one rhinovirus, as defined in the section "Rhinoviruses" herein above, linked, by a covalent linkage, to (ii) an amino acid sequence which is at least 90% identical, in particular at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence located in the last 363 C-terminal amino acids of the RNApolymerase of the same or of a different rhinovirus. For instance, a fusion peptide comprising any VP4 amino acid sequence of a rhinovirus strain which is at least 90% identical to the VP4 peptide of the HRV16 serotype (SEQ ID NO: 1) or of the HRV14 serotype (SEQ ID NO: 2) linked to any amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of the HRV16 serotype (SEQ ID NO: 13) or of the HRV14 serotype (SEQ ID NO: 14) is suitable for the purpose of the invention. Preferably the C-terminal end of the VP4 amino acid sequence is covalently linked by a peptide bond to the N-terminal end of the C-terminal domain of the RNA polymerase amino acid sequence In particular, said amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus is an amino acid sequence constituted of about from 100 to 363 consecutive amino acids of the RNA polymerase amino acid sequence, more particularly of from 105 to 350 consecutive amino acids, 110 to 340, 120 to 330, 140 to 320, 160 to 300, 180 to 280, 200 to 260 or 220 to 240 consecutive amino acids. In particular, the present inventors demonstrated that a fusion peptide comprising the last 105 C-terminal amino acids of the RNA polymerase retained the ability to induce a cross-reactive immune response. Accordingly, in a particular embodiment, the amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus included in the fusion peptide of the immunogenic composition according to the invention consists of the last 105 C-terminal amino acids of the RNA polymerase of a rhinovirus, as defined in the section "Rhinoviruses" herein above. More particularly, the amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus included in the fusion peptide of the immunogenic composition according to the invention consists of the last 105 C-terminal amino acids of the RNA polymerase of HRV16, said last 105 C-terminal amino acids consisting typically of the sequence: ADKSSEFKELDYGNVTFLKRGFRQDDKYKFLIHPTFPVEEIYESIRWTKKPSQMQEHVLS LCHLMWHNGPEIYKDFETKIRSVSAGRALYIPPYELLRHEWYEKF(SEQ ID NO: 9). In another embodiment, the amino acid sequence located in the last 363 Cterminal amino acids of the RNApolymerase of a rhinovirus included in the fusion peptide of the immunogenic composition according to the invention consists of the last 105 Cterminal amino acids of the RNA polymerase of HRV14, said last 105 C-terminal amino acids consisting typically of the sequence: PDKSETFTKMTWENLTFLKRYFKPDQQFPFLVHPVMPMKDIHESIRWTKDPKNTQDHV RSLCMLAWHSGEKEYNEFIQKIRTTDIGKCLILPEYSVLRRRWLDLF(SEQ ID NO: 10). According to another embodiment, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 90% identical, at least 95% identical, in particular at least 96% identical, 97%, 98%, 99% or 100% identical to the VP4 amino acid sequence of a rhinovirus, as defined in the section "Rhinoviruses" herein above, linked, by a covalent linkage, in particular a peptide bond, to (ii) an amino acid sequence which is at least 90% identical, in particular at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence located in the VP2 amino acid sequence of the same or of a different rhinovirus, as defined in the section "Rhinoviruses" herein above, which is linked, by a covalent linkage, in particular a peptide bond, to (iii) an amino acid sequence which is at least 90% identical, in particular at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of the same or of a different rhinovirus. For instance a fusion peptide comprising any VP4 amino acid sequence of a rhinovirus strain which is at least 90% identical to the VP4 peptide of the HRV16 serotype (SEQ ID NO: 1) or of the HRV14 serotype (SEQ ID NO: 2) coupled to any amino acid sequence located in the VP2 amino acid sequence of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence located in the VP2 amino acid sequence of the HRV16 serotype (SEQ ID NO: 3) or of the HRV14 serotype (SEQ ID NO: 4), which is coupled to any amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of a rhinovirus strain which is at least 90% identical to the corresponding amino acid sequence located in the last 363 C-terminal amino acids of the RNA polymerase of the HRV16 serotype (SEQ ID NO: 13) or of the HRV14 serotype (SEQ ID NO: 14) is suitable for the purpose of the invention. Preferably the C-terminal end of the VP4 amino acid sequence is covalently linked by a peptide bond to the N-terminal end of the VP2 amino acid sequence and the C-terminal end of said VP2 amino acid sequence is covalently linked by a peptide bond to the N-terminal end of the C-terminal domain of the RNApolymerase sequence. In particular, the fusion peptide of the immunogenic composition according to the invention comprises, or consists of, an amino acid sequence which is at least 80% identical, more particularly at least 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence consisting of the first 135 N-terminal amino acids of the VPo polyprotein of a rhinovirus, linked, by a covalent linkage, in particular a peptide bond, to (ii) an amino acid sequence which is at least 90% identical, in particular at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence located in the last 363 Cterminal amino acids of the RNA polymerase of the same or a different rhinovirus. More particularly, the fusion peptide of the immunogenic composition according to the invention comprises, or consists, of an amino acid sequence which is at least 80% identical, in particular at least 85% identical, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence MGAQVSRQNVGTHSTQNMVSNGSSLNYFNINYFKDAASSGASRLDFSQDPSKFTDPVKD VLEKGIPTLQSPSVEACGYSDRIIQITRGDSTITSQDVANAWGYGVWPHYLTPQDATAID KPTQPDTSSNRFYTLADKSSEFKELDYGNVTFLKRGFRQDDKYKFLIHPTFPVEEIYESIR WTKKPSQMQEHVLSLCHLMWHNGPEIYKDFETKIRSVSAGRALYIPPYELLRHEWYEKF (SEQ ID NO: 11). In another particular embodiment of the invention, the fusion peptide of the immunogenic composition of the invention comprises, or consists, of an amino acid sequence which is at least 80% identical, in particular at least 85% identical, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence MGAQVSTQKSGSHENQNILTNGSNQTFTVINYYKDAASTSSAGQSLSMDPSKFTEPVKDL MLKGAPALNSPNVEACGYSDRVQQITLGNSTITTQEAANAWCYAEWPEYLPDVDASDV NKTSKPDTSVCRFYTLPDKSETFTKMTWENLTFLKRYFKPDQQFPFLVHPVMPMKDIHE SIRWTKDPKNTQDHVRSLCMLAWHSGEKEYNEFIQKIRTTDIGKCLILPEYSVLRRRWLD LF (SEQ ID NO: 12). Nucleic acids The present invention also relates to an immunogenic composition comprising an isolated polynucleotide comprising a nucleic acid sequence corresponding to (i.e. encoding) at least one of the peptide a) or b) defined in the section "Peptides" herein above, or fusion peptide defined in the section "Fusion peptides" herein above and designed such that it can be administered to mammals, in particular to human beings. Usually the nucleic acid sequence placed under the control of the elements necessary for its expression in a mammalian cell, in particular in human cells, is incorporated in a plasmid, which can be further formulated in a delivery vehicle such as liposomes to facilitate its introduction into the host cell. As used herein, the term "nucleic acid" includes DNA and RNA and can be either double stranded or single stranded. In the context of the invention, the expression "elements necessary for expression in a mammalian cell" is understood to mean all the elements which allow the transcription of a DNAor DNAfragment into mRNA and the translation of the latter into protein, inside a mammalian cell, such as a human cell. Typically, the elements necessary for the expression of a nucleic acid in a mammalian cell include a promoter that is functional in the selected mammalian cell and can be constitutive or inducible; a ribosome binding site; a start codon (ATG) if necessary; a region encoding a signal peptide (e.g., a lipidation signal peptide); a stop codon; and a 3' terminal region (translation and/or transcription terminator). Other transcription control elements, such as enhancers, operators, and repressors can be also operatively associated with the polynucleotide to direct transcription and/or translation into the cell. The signal peptide-encoding region is preferably adjacent to the nucleic acid included in the immunogenic composition of the invention and placed in proper reading frame. The signal peptide-encoding region can be homologous or heterologous to the DNA molecule encoding the mature peptide or fusion peptide of the invention and can be specific to the secretion apparatus of the host used for expression. The open reading frame constituted by the nucleic acid included in the immunogenic composition of the invention, solely or together with the signal peptide, is placed under the control of the promoter so that transcription and translation occur in the host system. Promoters, (and signal peptide encoding regions) are widely known and available to those skilled in the art. Lastly, the nucleic acid sequences may be codon optimized such that the transcription of the DNA encoding the peptides and/or the fusion peptides of the invention is enhanced and/or the translation of the mRNA encoding the peptides and/or the fusion peptides is prolonged. A "codon-optimized DNA or mRNA sequence" means a nucleic acid sequence that has been adapted for a better expression into the host cell, such as a human cell by replacing one or more codons with one or more codons that are more frequently used in the genes of said host cell as described in US 2004/0209241 in the case of codonoptimized DNA sequences or to maximize the G/C content of the mRNA sequence according to the host cell used as described in US 2011/02699950 in the case of codonoptimized mRNA sequences. The codon optimization of the nucleic acid sequences is properly managed such that it does not change significantly the amino acid sequence of the peptides and/or the fusion peptides, as described in the sections "Peptides" and "Fusion peptides "herein above, which are expressed in the host cells. Immunogenic composition In the context of the invention, the expression "immunogenic composition" refers to a composition of matter intended to be administered to a subject that comprises at least one antigen or induces the expression of at least one antigen of a rhinovirus (in the case of nucleic acid immunization) which has the capability to elicit an immunological response in the subject to which it is administered. Such an immune response can be a cellular and/or antibody-mediated immune response directed at least against the antigen of the composition. More specifically, the immunogenic composition of the invention comprises an isolated peptide as defined in the section "Peptides" herein above, a fusion peptide as defined in the section "Fusion peptides" herein above and/or an isolated polynucleotide as defined in the section "Nucleic acids" herein above. When the immunogenic composition of the invention comprises at least one peptide as defined in the section "Peptides" herein above and/or at least one fusion peptide as defined in the section "Fusion peptides" herein above, it also comprises a Thi adjuvant. A "Thi adjuvant" in the meaning of the invention is defined from the ratio between IFN-g and IL-5 cytokines that are produced by the splenocytes of mice that have been previously immunized by subcutaneous route with a peptide or a fusion peptide of the immunogenic composition according to the invention in presence of the tested adjuvant. More specifically, the splenocytes are harvested 28 days after the immunization and restimulated in vitro with a pool of 15 mers peptides (able to be presented by class I and II MHC) overlapping on 11 amino acids, covering the amino acid sequence of the same peptide or fusion peptide in a culture medium according to the protocol described in example 3. After 3 days of stimulation, culture supernatants are harvested for measuring IFN-g and IL-5 cytokines by Cytometry Bead Array. If the ratio IFN-y/IL- is >5, preferably >io, the tested adjuvant is considered as a Thi adjuvant. Examples of Thi adjuvants promoting a Thi immune response include TLR-9 agonists such as CpG oligonucleotides, or TLR-4 agonists. In a particular embodiment, the Thi adjuvant used in the immunogenic compositions of the invention comprises a CpG oligonucleotide. It can be used in an aqueous solution, formulated in Oil in water Emulsion, for instance with incomplete Freund's adjuvant or delivered by other means. As examples of suitable CpG oligobucleotide sequences mention is made of CpG ODN 1826 (sequence 5'- TCCATGACGTTCCTGACGTT-3' (SEQ ID NO: 38)), CpG ODN 2216 (sequence 5'ggGGGACGATCGTCggggg-3' (SEQ ID NO: 39)), CpG 2336 (sequence 5'- gggGACGACGTCGTGgggggg-3' (SEQ ID NO: 40)), or CpG 7909 (5'- TCGTCGTTTTGTCGTTTTGTCGTT-3' (SEQ ID NO: 41)), but other stimulatory sequences can be used for the purpose of the invention. The immunogenic compositions of the invention can further comprise a pharmaceutically acceptable vehicle. In the context of the invention, the expression "pharmaceutically acceptable vehicle" refers to a vehicle that is physiologically acceptable to a treated mammal, in particular to humans, while retaining the prophylactic or therapeutic properties of the compound with which it is administered. One exemplary pharmaceutically acceptable vehicle is physiological saline. Other physiologically acceptable vehicles and their formulations are known to those skilled in the art and examples are described, for example, in Remington's Pharmaceutical Sciences, (18th edition), ed. A. Gennaro, 1990, Mack Publishing Company, Easton, Pa.. The compositions can be formulated for use in a variety of drug delivery systems. One or more physiologically acceptable excipients or carriers can also be included in the compositions for proper formulation. The immunogenic compositions can be administered intranasally (e.g., by aerosol inhalation or nose drops), parenterally (e.g., by intramuscular, subcutaneous, intravenous route, intradermally, transcutaneously, transdermally or percutaneously), cutaneously, orally, mucosally, intrapulmonary and/or by intratracheal delivery, or by topical application. Sustained release administration is also encompassed in the invention, by such means as depot injections or erodible implants or components. Thus, the invention provides immunogenic compositions for mucosal or parenteral administration that include the peptides as defined in the section "Peptides" herein above, the fusion peptides as defined in the section "Fusion peptides" in the presence of the Thi adjuvant as defined above, and/or the polynucleotides as defined in the section "Nucleic acids" herein above, dissolved or suspended in an acceptable vehicle, preferably an aqueous carrier, e.g., water, buffered water, saline, PBS, and the like. The immunogenic compositions may contain pharmaceutically acceptable auxiliary substances as required to approximate physiological conditions, such as pH adjusting and buffering agents, tonicity adjusting agents, wetting agents, detergents and the like. The invention also provides immunogenic compositions for oral delivery, which may contain inert ingredients such as binders or fillers for the formulation of a tablet, a capsule, and the like. Further, this invention provides immunogenic compositions for cutaneous or local administration, which may contain inert ingredients such as solvents or emulsifiers suitable for penetration through the skin, for the formulation of a cream, an ointment, or incorporation in a patch. For oral administration, the immunogenic composition may be of any of several forms including, for example, a capsule, a tablet, a suspension, or liquid, among others. Injectable preparations, under the form of sterile injectable aqueous solutions or suspensions, such as liposomes, or emulsions such as Oil in Water emulsions, may be formulated according to known methods using suitable dispersing, wetting agents, suspending agents, emulsifying agents and the like. Suitable vehicles and solvents that may be employed are water, Ringer's solution, isotonic sodium chloride solution, phosphate or Tris buffer among others. In addition, sterile, fixed oils are conventionally employed for the preparation of emulsions. For this purpose, any bland fixed oil may be employed, including synthetic mono- or diglycerides, squalene. The immunogenic compositions may also be prepared in a solid form (including granules, powders or suppositories). These immunogenic compositions may be sterilized by conventional sterilization techniques, or may be sterile filtered. The resulting aqueous solutions may be packaged and stored under liquid form or lyophilized, the lyophilized preparation being reconstituted with a sterile aqueous carrier prior to administration. The pH of the preparations typically will be between 3 and 11, e.g., between 5 and 9, 6 and 8, or 7 and 8, such as 7 to 7.5. The resulting compositions in solid form may be packaged in multiple single dose units, each containing an effective amount of peptides as defined in the section "Peptides" herein above, fusion peptides as defined in the section "Fusion peptides" , and a Thi adjuvant, and/or polynucleotides as defined in the section "Nucleic acids" herein above, such as in a vial. If there is an incompatibility between the Thi adjuvant and the peptide or fusion peptide, they can be stored in separate packages and mixed extemporaneously before administration to the subject. The immunogenic composition according to the present invention may be prepared using any conventional method known to those skilled in the art. Conventionally the peptides and/or fusion peptides according to the invention are mixed with a pharmaceutically acceptable diluent or excipient, such as water or phosphate buffered saline solution, wetting agents, fillers, emulsifier and stabilizer. The excipient or diluent will be selected as a function of the pharmaceutical form chosen, of the method and route of administration and also of pharmaceutical practice. Suitable excipients or diluents and also the requirements in terms of pharmaceutical formulation, are described in Remington's Pharmaceutical Sciences, which represents a reference book in this field. Medical indications The present invention also concerns a method for inducing a specific cross-reactive cell-mediated immune response in a mammal directed against at least two serotypes of rhinoviruses, more particularly against at least two serotypes of type A and/or type B rhinoviruses, comprising administering to a mammal an effective amount of an immunogenic composition as defined in the section "Immunogenic composition" herein above. The present invention further concerns an immunogenic composition as defined in the section "Immunogenic composition" herein above " for use in a mammal to induce a cross-reactive cell-mediated immune response against at least two serotypes of rhinoviruses, in particular against at least two serotypes of type A and/or type B rhinoviruses. The present invention also concerns the use of a peptide a) or b) as defined in the section "Peptides" herein above or a polynucleotide as defined in the section "Nucleic acids" herein above, for the manufacture of an immunogenic composition intended to induce a cross-reactive cell-mediated immune response against at least two serotypes of rhinoviruses, in particular against at least two serotypes of type A and/or type B rhinoviruses in a mammal. Primarily the immune response that is induced by an immunogenic composition of the invention is a specific cell-mediated immune response not only directed to the homologous serotype(s) of rhinovirus from which the immunogenic composition is derived but also to other (heterologous) serotypes of rhinoviruses of the same group of rhinoviruses, which can extend to serotypes of rhinoviruses of another group of rhinoviruses. In particular, the cell-mediated immune response induced by an immunogenic composition of the invention overtakes the "inter-group barrier" because it is in particular directed against serotypes of type A and type B rhinoviruses. Such cellular immune response is named specific cross-reactive cellular immune response (or specific cross-reactive cell-mediated immune response), insofar it is not limited to the homologous serotype of rhinovirus against which the subject has been immunized. The cell-mediated immune response induced by the immunogenic composition of the invention is Thiand/ or Tci-oriented. In the context of the invention, the expression "inducing a specific cell-mediated immune response" means the generation of a specific T lymphocyte response following the administration of an immunogenic composition in a subject. The two main cellular effectors of the specific T lymphocyte response are the helper T-cells and the cytototoxic T lymphocytes (CTLs). CD4+ "helper" T-cells or helper T-cells, are immune response mediators, and play an important role in establishing and maximizing the capabilities of the adaptive immune response. These cells can have to some extent a direct cytotoxic activity, but, in essence "manage" the immune response, by directing other cells involved in the protection of organisms against pathogens. The activation of a naive helper T-cell causes it to release cytokines, which influences the activity of many cell types such as B lymphocytes, CTLs, and APCs (Antigen Presenting Cells) that activated it. Helper T-cells require a much milder activation stimulus than cytotoxic T-cells. Helper T-cells can provide extra signals that "help" activate cytotoxic cells. Two types of effector CD4+ helper T cell responses can be induced by a professional APC, designated Thi and Th2. The measure of cytokines associated with Thi or Th2 responses will give a measure of successful immunization. This can be achieved by specific ELISA or ELISPOT designed for measurement of Thicytokines such as IFN-g, IL-2, and others, or Th2- cytokines such as IL-4, IL-5, IL-13 among others. As used herein, the expression "helper T-cell-mediated immune response" refers to an immune response wherein CD4+ T-cells or helper T-cells are activated and secrete lymphokines to stimulate both cell-mediated and antibody-mediated branches of the immune system. As known from the skilled person, helper T-cell activation promotes lymphokine secretion, immunoglobulin isotype switching, affinity maturation of the antibody response, macrophage activation and/or enhanced activity of natural killer and cytotoxic T-cells. Lymphokines are proteins secreted by lymphocytes that affect their own activity and/or the activity of other cells. Lymphokines include, but are not limited to, interleukins and cytokines, e.g., IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, or IFN-g. As well-known from the skilled person, helper T-cells differentiate into two major subtypes of cells known as Thi and Th2 cells (also known as Type 1 and Type 2 helper T cells, respectively). As known from the skilled person, Thi cells mainly secrete IL-2 and IFN-g. They promote cellular immune response by maximizing the killing efficacy of macrophages and the proliferation of cytotoxic CD8+ T-cells. Additionally, the type 1 cytokine IFN-g increases the production of IL-12 by dendritic cells and macrophages, and, via positive feedback, IL-12 stimulates the production of IFN-g in helper T-cells, thereby promoting the Thi profile. IFN-g also inhibits the production of cytokines such as IL-4, an important cytokine associated with the Type 2 response, and thus it also acts to preserve its own response. On the contrary, Th2 cells mainly secrete IL-4, IL-5 and IL-13, nd promote humoral immune response by stimulating B cells into proliferation, inducing B-cell antibody class switching. The Type 2 response further promotes its own profile using two different cytokines. IL-4 acts on helper T-cells to promote the production of Th2 cytokines (including itself), while IL-10 inhibits a variety of cytokines including IL-2 and IFN-g in helper T-cells and IL-12 in dendritic cells and macrophages. Preferably, said cell-mediated immune response induced by the immunogenic composition of the invention is primarily a Thi cell-mediated immune response. The induction of a Thi oriented cell-mediated immune response by the immunogenic composition of the invention may be determined from the ratio between IFN-g and IL-5 cytokines that are produced by the splenocytes of mice that have been previously immunized by subcutaneous route with the immunogenic composition according to the invention. More specifically, the splenocytes are harvested 28 days after the immunization and stimulated in vitro with a pool of 15 mers peptides overlapping on 11 amino acids covering the amino acid sequence of the peptide or fusion peptide included in the immunogenic composition or encoded by a nucleic acid included in the immunogenic composition, in a culture medium according to the protocol described in example 3. After 3 days of stimulation, culture supernatants are harvested for measuring IFN-g and IL-5 cytokines by Cytometry Bead Array. If the ratio IFN-y/IL-5 is >5, preferably >io, the immune response induced is a Thi oriented cell-mediated immune response. Furthermore, since the Thi oriented cell-mediated immune response is a crossreactive cell-mediated immune response, the splenocytes harvested 28 days after immunization can also be stimulated in vitro with a pool of 15 mers peptides overlapping on 11 amino acids, covering the amino acid sequence of a corresponding peptide or fusion peptide from at least one other serotype of type A and/or type B rhinovirus and produce in the cell culture supernatant amounts of IFN-g and IL-5 cytokines such that the ratio IFNy/ IL-5 is >5, preferably >io after dosing by Cytometry Bead Array. In the context of the invention, a Tci response may also be observed in addition to the Thi cell-mediated immune response. Cytotoxic T cells (also known as Tc, killer T cell, or cytotoxic T-lymphocyte (CTL)), which express generally the CD8 marker, are a sub-group of T cells and may also be involved in the T cell-mediated immune response. They induce the death of cells that are infected with viruses (and other pathogens). These CTLs directly attack other cells carrying certain foreign or abnormal molecules on their surface. The ability of such cellular cytotoxicity can be detected using in vitro cytolytic assays (chromium release assay). Thus, induction of a specific cellular immunity can be demonstrated by the presence of such cytotoxic T cells, when antigen-loaded target cells are lysed by specific CTLs that are generated in vivo following vaccination or infection. Similarly to helper T-cells, CD8+ T-cells include distinct subsets, which were termed, analogously to the Thi/Th2 terminology, Tci and Tc2. The Tci immune response involves specific IFN-y-producing CD8+ T-cells which are activated, proliferate and produce IFN-g upon specific antigen stimulation. The level of IFN-y-producing CD8+ T-cells can be measured by ELISPOT and by flow cytometry measurement of intracellular IFN-g in these cells. Naive cytotoxic T cells are activated when their T-cell receptor (TCR) strongly interacts with a peptide-bound MHC class I molecule. This affinity depends on the type and orientation of the antigen/MHC complex, and is what keeps the CTL and infected cell bound together. Once activated the CTL undergoes a process called clonal expansion in which it gains functionality, and divides rapidly, to produce an army of "armed" effector cells. Activated CTL will then travel throughout the body in search of cells bearing that unique MHC Class I + peptide. This could be used to identify such CTLs in vitro by using peptide-MHC Class I tetramers in flow cytometric assays. When exposed to these infected cells, effector CTL release perforin and granulysin, cytotoxins which form pores in the target cell's plasma membrane, allowing ions and water to flow into the infected cell, and causing it to burst or lyse. CTL release granzyme, a serine protease that enters cells via pores to induce apoptosis (cell death). Release of these molecules from CTL can be used as a measure of successful induction of cellular immune response following vaccination. This can be done by enzyme linked immunosorbant assay (ELISA) or enzyme linked immunospot assay (ELISPOT) where CTLs can be quantitatively measured. Since CTLs are also capable of producing important cytokines such as IFN-g, quantitative measurement of IFN-y-producing CD8 cells can be achieved by ELISPOT and by flow cytometric measurement of intracellular IFN-g ίh these cells. In particular, the induction of a Tci immune response by the immunogenic composition of the invention may be determined from the level of IFN-g cytokine that is produced in CD8+ T-cells of mice that have been previously immunized by subcutaneous route with the immunogenic composition according to the invention. More specifically, the splenocytes are harvested 28 days after the immunization and stimulated in vitro with a pool of 15 mers peptides overlapping on 11 amino acids covering the amino acid sequence of the peptide or fusion peptide included in the immunogenic composition or encoded by a nucleic acid included in the immunogenic composition, in a culture medium. Brefeldin A (BFA) is added to inhibit cytokine secretion, and cells are stimulated for 5 h, followed by overnight storage. The following day, cells are permeabilized, fixed, stained, and the percentage of CD8+ IFN-g - and CD8+ ILs+ cells in the splenocyte population is measured by flow cytometry after intracellular cytokine staining (ICS). If the ratio CD8+ IFN-g +/ CD8+ ILs+ is higher than 1, the immune response is considered as a Tci immune response. In the context of the invention, the expression "inducing a cross-reactive immune response" means that an immune response is induced both against the HRV serotype from which the peptide, fusion peptide or nucleic acid included in the immunogenic composition of the invention is derived (i.e. "cellular immune response to the homologous serotype"), and against at least a second HRV serotype different from the HRV serotype from which the peptide, fusion peptide or nucleic acid included in the immunogenic composition of the invention is derived (i.e. "cellular immune response to the heterologous serotype"). Therefore, in an embodiment, the peptide, fusion peptide and/or nucleic acid of the immunogenic composition of the invention induce a cellular immune response to both homologous and heterologous serotypes of rhinoviruses, as defined above. More particularly, an immune response may be induced both against the HRV serotype from which the peptide, fusion peptide or nucleic acid included in the immunogenic composition of the invention is derived, and against at least a second HRV serotype which is of a different group from the HRV serotype from which the peptide, fusion peptide or nucleic acid included in the immunogenic composition of the invention is derived. In other words, an inter-group reactive immune response may be induced by the immunogenic composition of the invention. In a particular embodiment, the peptide, fusion peptide and/or nucleic acid of the immunogenic composition of the invention are derived from a serotype of type A rhinoviruses, in particular from HRV16, HRV29 or HRViB, and an immune response is induced against the same serotype of type A rhinoviruses and at least another serotype of type A and/or type Brhinoviruses, in particular HRV14. In another particular embodiment, the peptide, fusion peptide and/or nucleic acid of the immunogenic composition of the invention are derived from a strain of type B rhinoviruses, in particular from HRV14, and an immune response is induced against the same serotype of type Brhinoviruses and at least another serotype of type B and/or type A rhinoviruses, in particular HRV16, HRV29 and/or HRViB. In another particular embodiment, the peptide, fusion peptide and/or nucleic acid of the immunogenic composition of the invention are from a strain of major-group type A or type B rhinoviruses, in particular from HRV16 or HRV14, and an immune response is induced against the same strain of major-group type A or type B rhinoviruses and at least another strain of minor-group type B or type A rhinoviruses, in particular HRViB and/or HRV29, and/or at least another strain of major-group type Aor type Brhinoviruses. Therefore, the cellular immune response induced by an immunogenic composition of the invention overtakes the "inter-group barrier" among rhinoviruses since it is at least directed against serotypes of type A Human rhinoviruses and type BHuman rhinoviruses. The immunogenic compositions according to the invention are therefore able to induce a cross-reactive cell-mediated immune response against several HRV serotypes which can also be considered as an inter-group cell-mediated immune response. In a particular embodiment, the cell-mediated immune response induced by the administration of the immunogenic compositions of the invention is boosted after infection by a rhinovirus. In the context of the invention, the phrase "cell-mediated immune response is boosted after infection by a rhinovirus" means the induction of a cross-reactive specific cell-mediated immune response after rhinovirus infection of subjects already immunized with an immunogenic composition of the invention. Although the peptide, fusion peptide and nucleic acid included in the immunogenic composition according to the invention were designed by the inventors to induce T cellmediated immune response, T cell help may also contribute to the development of an effective humoral immune responses. The effect of immunization with the immunogenic composition of the invention on the humoral immune response to subsequent infection with a rhinovirus was also studied by the inventors to determine if immunization-induced T cell-mediated immune responses could indirectly enhance this aspect of immunity. The present inventors demonstrated that, while only administering the immunogenic compositions of the invention to a subject induced a cross-reactive non neutralizing antibody response, it advantageously enabled inducing a specific neutralizing antibody response when a rhinovirus infection occurred in said subject. Furthermore, the clearance of rhinovirus infection was very fast. The present invention therefore also concerns a method for inducing a specific neutralizing antibody response in a mammal when said mammal is infected by a rhinovirus, comprising administering to a mammal an effective amount of an immunogenic composition as defined in the section "Immunogenic composition" herein above. The present invention further concerns an immunogenic composition as defined in the section "Immunogenic compositions" herein above, for use in a mammal (i.e. in humans) to induce a specific neutralizing antibody response when said mammal is infected by a rhinovirus. The present invention also concerns the use of a peptide as defined in the section "Peptides" herein above or a nucleic acid as defined in the section "Nucleic acids" herein above, for the manufacture of an immunogenic composition intended to induce a specific neutralizing antibody response in a mammal when said mammal is infected by a rhinovirus. In the context of the invention, a "neutralizing antibody" refers to an antibody which prevents the replication cycle of rhinoviruses to occur in permissive cells of a subject. Permissive cells are cells that allow the penetration and the multiplication of the virus. In the context of the invention, lung cells are highly permissive to rhinovirus infection. In a particular embodiment, the immunogenic composition as defined in the section "Immunogenic compositions" herein above, is therefore for use in a mammal to induce a specific cross-reactive cell-mediated immune response against at least two serotypes of rhinoviruses followed by a specific neutralizing antibody response when said mammal is infected by said rhinoviruses. The immunogenic compositions of the invention can thus be administered for prophylactic ("cross-protective") treatments. In prophylactic applications, immunogenic compositions can be administered to a subject (e.g. a human subject) with increased susceptibility to HRV infection. Immunogenic compositions of the invention will be administered to a subject in an amount sufficient to accelerate virus clearance, to reduce or prevent the onset of clinical or subclinical disease or avoid viral complications associated with the infectious virus in the body, in particular in the lungs. The present invention therefore also concerns a method to shorten or prevent rhinovirus infection in a mammal, and/or to reduce or prevent the clinical symptoms associated with the infection in a mammal, comprising administering to a mammal an effective amount of an immunogenic composition as defined in the section "Immunogenic composition" herein above. The present invention further concerns an immunogenic composition as defined in the section "Immunogenic composition" herein above for use to shorten or prevent rhinovirus infection in a mammal and/or to reduce or prevent the clinical symptoms associated with the infection. The present invention also concerns the use of a peptide as defined in the section "Peptides" herein above or a nucleic acid as defined in the section "Nucleic acids" herein above, for the manufacture of an immunogenic composition intended to shorten or prevent rhinovirus infection in a mammal and/or to reduce or prevent the clinical symptoms associated with the infection. Since the immunogenic composition of the invention protects at least to some extent against infection by rhinoviruses, it is therefore suitable for use as a vaccine to prevent rhinovirus infection. As used herein, the term "vaccine" refers to as an immunogenic composition intended to elicit an immune response with the aim to establish full or partial protecting immunity to disease, in particular against infective disease. Determination of an appropriate dosage amount and regimen can readily be determined by those skilled in the art. The immunogenic composition can be only administered once but a prime/boost regimen is generally used. Usually at least one or two boosting doses subsequent to priming dose are given to the subject. Time interval between each immunization may vary according to the subject to be immunized or other factors such as the formulation or the route of administration of the immunogenic composition but usually a time interval of at least 15 days, at least one month, at least two months or at least six months are respected between each immunization. The effective amount of the immunogenic composition of the invention applied to mammals (e.g., humans) can be determined by those skilled in the art with consideration of individual differences in age, weight, immune system integrity, and the like, such that it produces the desirable effect in the immunized subject, which is at least the shortening of virus infection and/or the lessening of clinical symptoms in the infected individual. Administration of an immunogenic composition of the present invention to a mammal may be accomplished using any of a variety of techniques known to those of skill in the art. The composition may be processed in accordance with conventional methods of pharmacy to produce medicinal agents for administration to patients, including humans and other mammals. As mentioned above, the immunogenic composition may be administered intranasally (e.g., by aerosol inhalation or nose drops), parenterally (e.g., by intramuscular, subcutaneous, or intravenous route, intradermally, transcutaneously, transdermally or percutaneously), cutaneously, orally, mucosally, intrapulmonary and/or by intratracheal delivery and/ or by topical application, in dosage unit formulations. While the compositions of the invention can be administered as the sole active pharmaceutical agent, they can also be used in combination with one or more other compositions or agents (i.e., other immunogenic targets, co-stimulatory molecules). When administered as a combination, the individual components can be formulated as separate compositions administered at the same time or different times, or the components can be combined as a single composition. All of the features described herein (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The present invention will be further illustrated by the following figures and examples. Brief description of the figures Figure l is a set of histograms representing the number of IFN-g (panel A) and IL-5 (panel B) producing cells (/10 6 cells), enumerated by ELISPOT in splenocytes of mice immunized subcutaneously with HRV16 VPo protein (RV16 VPo) or buffer, with or without IFA/CpG adjuvant (IFA/Cpg), after stimulation of splenocytes with VPo from HRViB (VPo RViB) or from HRV14 (VPo RV14) or with 3'Pol peptide pools from HRViB (3'Pol RViB) or from HRV14 (3'Pol RV14), the splenocytes being harvested 28 days postimmunization. n = 10 mice/group. *** : p