Immunochemical identification of viral and nonviral proteins of the respiratory syncytial virus virion.

We identified by immunochemical methods 13 polypeptides associated with the infectious respiratory syncytial virus virion. Eight of these polypeptides (VP200, VP84, VP66, VP43, VP40, VP37, VP28, and VP19) were identified as virus specific. Two other polypeptides, (VP) 22 and (VP) 12, are provisionally considered to be of viral origin. Three nonviral proteins are also intimately associated with the infectious virion. These nonviral proteins were identified as cellular actin and two proteins with bovine serum albumin immunospecificity. VP40 was identified as the major ribonucleoprotein. Based on biochemical and biophysical similarities with paramyxovirus proteins, other respiratory syncytial virus proteins are believed to have these specific viral functions: VP84, "hemagglutinin"; VP66, undissociated fusion protein, F1,2; VP43, F1; and VP19, F2, VP66 contains a major determinant involved in viral infectivity since all neutralizing antibodies tested, including a monoclone, precipitated this protein.