Clearance of antibody and complement in serum after challenge of mice previously vaccinated or infected with influenza virus.

Mice previously vaccinated or convalescent after infection with mouse-adapted influenza virus were challenged by various routes with live or inactivated virus. The levels of haemagglutination inhibiting and complement-fixing antibodies and complement in serum were found to decrease distinctly within several hours after challenge: the reconstitution to initial levels occurred within three days.