We have developed a novel cross-immune antigen vaccine platform for influenza A virus. The vaccine antigen is a fusion protein of headless hemagglutinin (HA) and matrix protein 1 (M1), which possess B-cell and T-cell epitopes, respectively, that are conserved among subgroup A viruses. The single molecule of headless HA and M1 fusion protein forms an oligomer by self-assembly of M1. T-Helper 1 (Th1) and Th2 cells were activated in an antigen-specific manner in lymphocyte cultures of antigen-immunized mice. The antigen-immunized antiserum neutralized influenza virus A subtypes H1N1 and H3N2, and intranasal administration of the antigen reduced mortality to less than 30% in a protection assay.
Keywords: antigen-specific T-helper 1 (Th1) response; conformational epitope; influenza virus type A; oligomer; universal vaccine.