Antigenic variation of envelope and internal proteins of mumps virus strains detected with monoclonal antibodies.

Antigenic characteristics of nine mumps virus strains were determined by immunofluorescence and radioimmunoprecipitation assay (RIPA) using a collection of 44 monoclonal antibodies. These antibodies were directed against five different structural components of mumps virus, the haemagglutinin-neuraminidase (HN), fusion (F), matrix (M), phospho- (P) and nucleocapsid (NP) proteins. The nine mumps virus strains could be divided into two groups according to their antigenic characteristics. One group included two strains isolated more than a decade ago and the Jeryl Lynn vaccine strain. These three strains reacted with a wider range of monoclonal antibodies than the second group of six recently isolated strains of different geographical origin. In the F, M and P proteins variations were only found in single antigenic determinants. In the HN and NP components, RIPA revealed variations in three and seven determinants respectively. The Jeryl Lynn vaccine strain showed a unique lack of reaction with one anti-HN antibody clone in the RIPA.