Preparation and Properties of Antibody Directed Specifically Against the Neuraminidase of Influenza Virus

Summary Antiserum was prepared against a recombinant influenza virus possessing A0 (NWS strain) type hemagglutinin and A2 (RI/5+) type neuraminidase. This antiserum was absorbed sequentially with NWS and A2 viruses and antibody directed against A2 type neuraminidase was then dissociated from the A2 virus. This antibody had no activity against the hemagglutinin activity of A0, A1 and A2 influenza viruses or against the infectivity of A0 and A1 viruses. It neutralized the enzyme activity of A2 but not A0 or A1 type influenza viruses. Anti-enzyme antibody caused apparent neutralization of the infectivity of influenza viruses possessing A2 type neuraminidase providing that the antibody was allowed to remain in contact with the cells during the test period. This antibody did not prevent infection of susceptible cells but apparently prevented the release of detectable levels of hemagglutinin. It had no effect on the infectivity of an A2 type recombinant virus that lacked neuraminidase activity.