The present inventors have found that innate immune response and T cell exhaustion pathway are more greatly over-expressed in pigs than cattle, such that the pigs are less likely to form adaptive and humoral immune responses than cattle. It would be suggested herein an innovative strategy for improvement of abnormal immune responses in pigs by simultaneously inducing potent cellular and humoral immune responses and applying T cell agonists as a new vaccine adjuvant. This result may provide an important clue for understanding a difference in the immune response between the cattle and pigs, while suggesting a method for maximizing the immune response and vaccine efficacy, which are less expressed in pigs than cattle.

The present inventors have found that innate immune response and T cell exhaustion pathway are more greatly over-expressed in pigs than cattle, such that the pigs are less likely to form adaptive and humoral immune responses than cattle. It would be suggested herein an innovative strategy for improvement of abnormal immune responses in pigs by simultaneously inducing potent cellular and humoral immune responses and applying T cell agonists as a new vaccine adjuvant. This result may provide an important clue for understanding a difference in the immune response between the cattle and pigs, while suggesting a method for maximizing the immune response and vaccine efficacy, which are less expressed in pigs than cattle.

The present invention is directed to novel promiscuous and artificial T helper cell epitopes (Th epitopes) designed to provide optimum immunogenicity of a target antigenic site. The target antigenic site can include a B cell epitope, a CTL epitope, a peptide hapten, a non-peptide hapten, or any immunologically reactive analogue thereof. The disclosed Th epitopes, when covalently linked to a target antigenic site in a peptide immunogen construct, elicit a strong B cell antibody response or an effector T cell response to the target antigenic site. The Th epitopes are immunosilent on their own, i.e., little, if any, of the antibodies generated by the peptide immunogen constructs will be directed towards the Th epitope, thus allowing a very focused immune response directed to the targeted antigenic site. The promiscuous artificial Th epitopes provide effective and safe peptide immunogens that do not generate inflammatory, anti-self, cell-mediated immune responses following administration.

The present invention is directed to novel promiscuous and artificial T helper cell epitopes (Th epitopes) designed to provide optimum immunogenicity of a target antigenic site. The target antigenic site can include a B cell epitope, a CTL epitope, a peptide hapten, a non-peptide hapten, or any immunologically reactive analogue thereof. The disclosed Th epitopes, when covalently linked to a target antigenic site in a peptide immunogen construct, elicit a strong B cell antibody response or an effector T cell response to the target antigenic site. The Th epitopes are immunosilent on their own, i.e., little, if any, of the antibodies generated by the peptide immunogen constructs will be directed towards the Th epitope, thus allowing a very focused immune response directed to the targeted antigenic site. The promiscuous artificial Th epitopes provide effective and safe peptide immunogens that do not generate inflammatory, anti-self, cell-mediated immune responses following administration.

The present invention relates to the preparation of the compound immunopotentiator and the application thereof in a foot-and-mouth disease vaccine of pigs. According to the present invention, the foot-and-mouth disease vaccine of pigs is taken as a research subject, and on this basis, several immunopotentiators having obvious immunopotentiating effects are selected for the compound immunopotentiator, and an antigen/vaccine is mixed with the immunopotentiator to prepare a vaccine-immunized pig. An animal experiment result shows that the present invention has obvious immunopotentiating effects. After immunizing the vaccine containing the compound immunopotentiator, a window period for antibody production can be significantly shortened to 7 days; a LPB-ELISA antibody titer is significantly improved, and an antibody pass rate is significantly increased; an immune protection period is also significantly extended, at least up to 7 months.

The present invention relates to the preparation of the compound immunopotentiator and the application thereof in a foot-and-mouth disease vaccine of pigs. According to the present invention, the foot-and-mouth disease vaccine of pigs is taken as a research subject, and on this basis, several immunopotentiators having obvious immunopotentiating effects are selected for the compound immunopotentiator, and an antigen/vaccine is mixed with the immunopotentiator to prepare a vaccine-immunized pig. An animal experiment result shows that the present invention has obvious immunopotentiating effects. After immunizing the vaccine containing the compound immunopotentiator, a window period for antibody production can be significantly shortened to 7 days; a LPB-ELISA antibody titer is significantly improved, and an antibody pass rate is significantly increased; an immune protection period is also significantly extended, at least up to 7 months.

The present disclosure provides a type A foot-and-mouth disease virus-like particle antigen assembled by VP2, VP3 and VP1 antigen proteins of an epidemic strain of type A foot-and-mouth disease virus. The type A foot-and-mouth disease virus VP2 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 1 or its degenerate sequence, the type A foot-and-mouth disease virus VP3 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 2 or its degenerate sequence, and the type A foot-and-mouth disease virus VP1 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 3 or its degenerate sequence.

The present disclosure provides a type A foot-and-mouth disease virus-like particle antigen assembled by VP2, VP3 and VP1 antigen proteins of an epidemic strain of type A foot-and-mouth disease virus. The type A foot-and-mouth disease virus VP2 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 1 or its degenerate sequence, the type A foot-and-mouth disease virus VP3 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 2 or its degenerate sequence, and the type A foot-and-mouth disease virus VP1 antigen protein is encoded by a nucleotide sequence shown in SEQ ID No. 3 or its degenerate sequence.

Synthetic foot-and-mouth disease virus (FMDV) mosaic polypeptides, and nucleic acid molecules encoding the mosaic polypeptides, are described. When included as part of an FMDV genome, the mosaic polypeptides permit virus replication and assembly into FMDV particles. The mosaic polypeptide and nucleic acid compositions can be used to elicit immune responses that provide protection against a broad range of serotype O FMDV strains.

Synthetic foot-and-mouth disease virus (FMDV) mosaic polypeptides, and nucleic acid molecules encoding the mosaic polypeptides, are described. When included as part of an FMDV genome, the mosaic polypeptides permit virus replication and assembly into FMDV particles. The mosaic polypeptide and nucleic acid compositions can be used to elicit immune responses that provide protection against a broad range of serotype O FMDV strains.