Proteins immunoprecipitated by track 1, rabbit hyperimmune antimeasles serum; track 2, rabbit preimmune control serum; tracks 3-5, monoclonal antibodies specific for the H protein; tracks 6-8, monoclonal antibodies specific for the Nprotein; tracks 9-16, monoclonal antibodies specific for the matrix protein; track 17, control monoclonal antibody, raised against coronavirus antigen; track 18, total infected cell lysate without immunoprecipitation.