The role of viral glycoproteins in mumps virus-mediated antibody-dependent cellular cytotoxity in vitro.
Treatment of human peripheral blood lymphocytes with live or UV-inactivated mumps virions enhances antibody-mediated cellular cytotoxicity (ADCC), reflected by increased target cell lysis in a 51Cr-release assay or an increased number of plaque-forming cells on monolayers of bovine erythrocytes (Eb) in the presence of anti-Eb antibodies. Virus treatment of the Eb targets causes a similar enhancement. The role of viral glycoproteins in ADCC enhancement was investigated by using a panel of monoclonal antibodies raised in mice against mumps virions. Most of the lymphocytes bound mumps virions, as ascertained by indirect immunofluorescence. A high proportion of virus-treated lymphocytes also formed rosettes with Eb. Anti-HN antibodies inhibited rosetting to various degrees. Although antibodies with high haemagglutination inhibition titres were most efficient inhibitors, antibodies without this serological activity were also inhibitory. Anti-F antibodies were only weakly inhibitory, and anti-NP antibodies had no effect. Anti-HN antibodies also abrogated target cell lysis in the 51Cr-release assay and effector cell recruitment in the ADCC plaque assay by inhibiting virus-mediated Eb-lymphocyte interactions both at the target cell and at the effector cell level. Anti-F or anti-NP antibodies were only weakly or not at all inhibitory. The results suggest that virus-mediated enhancement of ADCC is caused by the HN glycoprotein, primarily (although perhaps not exclusively) by its improvement of the effector cell-target cell contacts necessary for the efficient execution of target cell lysis.
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity; D000956:Antigens, Viral / Q000276:immunology*; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D008214:Lymphocytes / Q000276:immunology*; D009109:Mumps virus / Q000276:immunology*; D012397:Rosette Formation; D014764:Viral Proteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes; D006023:Glycoproteins; D014764:Viral Proteins