Protective Effects of Specific Immunity to Viral Neuraminidase on Influenza Virus Infection of Mice

Abstract

Antibody specific for viral neuraminidase can be demonstrated in mice following pulmonary infection with influenza virus, immunization with UV inactivated influenza virus, immunization with isolated neuraminidase of influenza A2 virus, and passive immunization with sera of rabbits immunized with isolated A2 neuraminidase. Neuraminidase antibody produced by any of these methods exerts a profound inhibiting effect on virus replication in the lungs of mice challenged with strains of virus having no homologous neuraminidase protein, even in the absence of hemagglutinating inhibiting antibody to the challenge virus, and results in markedly decreased pulmonary virus titers and diminished lung lesions. Antineuraminidase immunity may play a significant role in the protection against influenza virus challenge observed in mice after infection or artificial immunization.