Natural influenza A virus infection of mice elicits strong antibody response to HA2 glycopolypeptide.

Abstract

Two influenza viruses, A/Dunedin/4/73 (H3N2) and A/Mississippi/1/85 (H3N2) were adapted to BALB/c mice. Groups of BALB/c mice were intranasally (i.n.) infected with either single dose of particular virus strain or successively with both virus strains and titers of serum antibodies against influenza virus antigens ("influenza virus antibodies") and those just against the HA2 part of hemagglutinin (HA) ("HA2 antibodies") were determined. Successive infection with virus strains Dunedin and Mississippi in interval of 21 days led to the strong increase of the proportion of anti-HA2 antibodies in sera, though whole antiviral titres remained in general unchanged. These observations confirmed that the HA2 glycopolypeptide (gp) part of influenza virus HA is very strong immunogen in natural infection.