Aerosol vaccination of mice with a live, temperature sensitive recombinant influenza virus

Abstract

Mice were vaccinated intranasally (i.n.) with small particle aerosols (SPA;2μm) or large particle aerosols (LPA;8μm) of an attenuated, temperature sensitive, recombinant A influenza (H3N2) virus, ts 1 [E]. Serum virus neutralizing and hemagglutination inhibition antibodies were detected for all vaccinated mice by 28 days. Bronchoalveolar wash fluids had increased levels of immunoglobulin (IgG, IgA) only in the i.n. vaccinated mice. Hemagglutination and virus neutralizing antibodies were detected in the SPA and i.n. vaccinated groups but not in the LPA vaccinates. Upon challenge with SPA of a mouse virulent H3N2 influenza virus total protection was obtained for the SPA and i.n. vaccinated mice, whereas only 89% of the LPA group survived. Replication of the challenge virus was significantly repressed in both the lower and upper respiratory tracts of the three groups of vaccinated mice compared to the nonvaccinated controls. The protection afforded the SPA and i.n. vaccinated mice was the same as measured for mice after recovery from earlier sublethal active infection with virulent virus.