[Immunogenic activity of the influenza virus dependent on ne uraminidase (author's transl)]

The immunity of mice to challenge with influenza virus was studied after immunization with killed influenza vaccine. The results showed the resistance of the animals developing early after one and two intranasal vaccinations to depend not only upon the hemagglutinating properties of the vaccine but also upon its neuraminidase activity. When mice were immunized with a vaccine the neuraminidase of which was blocked with specific antibody or inactivated by heating and formalin, the protective effect against challenge with influenza virus decreased 2-3-fold as compared to that of the vaccine possessing active neuraminidase.