Indication and study of antigenic properties of influenza virus internal proteins by means of monoclonal antibodies.

Influenza A and B viruses isolated from animals and man were studied by solid phase radioimmunoassay (SP RIA) using monoclonal antibodies to the A/Dunedin/4/73 strain nucleoprotein (NP). Only influenza A viruses isolated before 1980 interacted with the monoclonal antibody set used, while strains isolated between 1980 and 1983 failed to do so. It was shown that RIA employing monoclonal antibodies was useful for rapid identification of influenza virus NP in the allantoic fluid containing fresh influenza A virus isolates.