Serological responses to whole and split A/New Jersey vaccines in humans and mice following priming infection with influenza A viruses.

Experiments were performed in mice to investigate the role of previous infection on responses to A/NJ/76 vaccines. Results from human studies have demonstrated that the serological responses to A/NJ/76 vaccines varied according to the age of the vaccinee and appeared to be related to their previous exposure to the different strains of influenza A virus. Mice were infected with influenza A viruses representative of the major strains (Hsw1N1, HON1, H2N2, H3N2) and later inoculated with varying doses of whole or subunit A/NJ/ML virus vaccines. Results from these experiments demonstrated a low antigenicity in non-primed mice of the subunit vaccine compared to whole-virus vaccine, but that the antigenicity of both vaccines was enhanced in mice primed by previous infection with earlier H0 and H1 viruses. The responses of heterotypically primed mice were qualitatively similar to those of primed humans following A/New Jersey vaccination.