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.

Synthetic alphavirus-derived replicon expression systems comprising nucleic acid sequences encoding at least one modified nonstructural protein, and synthetic nucleic acid sequences encoding at least one heterologous protein are described. Methods of producing at least one heterologous protein in a cell, or of inducing an immune response in a subject by administering and/or expressing the synthetic alphavirus-derived replicon expression systems are provided.

Provided is a swine fever antigen fused with a porcine Fc fragment, and more particularly, to a vaccine composition having an autoimmune-enhancing effect by binding the Fc fragment to a swine fever antigen, and a preparation method thereof.

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.

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.

A method of producing purified FMDV VLPs, comprising contacting cells containing FMDV VLPs with a lysis buffer and allowing the cells to lyse, the lysis buffer comprising 10-20 mM Tris-HCl, 150-200 mM NaCl, 3 mM MgCl.sub.2, and 1% Triton X-100, wherein the lysis buffer does not contain EDTA; centrifuging a solution; and removing a supernatant from the solution, the supernatant containing the purified FMDV VLPs.

The present invention provides for a novel oil-in-water (O/W) emulsion, with increased stability in the presence of bacterial or viral suspensions, especially those concentrated and non-purified (crude extracts) or minimally purified. The emulsion of the present invention can act as vehicle for the delivery of a pharmaceutical composition comprising at least one immunogen and, in particular, an immunogen selected from the group consisting of an inactivated pathogen, an attenuated pathogen, a subunit, a recombinant expression vector, and a plasmid or combinations thereof.

The present invention encompasses FMDV vaccines or compositions. The invention encompasses recombinant vectors encoding and expressing FMDV antigens, epitopes or immunogens which can be used to protect animals, in particular ovines, bovines, caprines, or swines, against FMDV.

This disclosure pertains to isolated antibodies or antigen binding fragments thereof that specifically bind to the 3ABC non-structural protein of Foot-and-Mouth Disease virus (FMDV), wherein the antibodies or antigen binding fragments thereof recognize the amino acid sequence of SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6 or SEQ ID NO: 12. Accordingly, this disclosure also pertains to polypeptides having an amino acid sequence selected from SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5 or SEQ ID NO: 12. Monoclonal antibody Mab 40C8 is also provided. The current disclosure also pertains to methods of detecting FMDV infection in an animal (including assays differentiating infected animals from vaccinated animals (DIVA)) and kits for performing the detection methods. Competitive ELISA kits comprising the antibody or antigen binding fragment thereof and immunoassay plates coated with the polypeptide comprising the amino acid sequence selected from SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6 and/or SEQ ID NO: 12 are also provided.