Staphylococcal protein A-sepharose columns and the characterization of measles virus-specific polypeptides in persistently infected cells.

Viral polypeptides in extracts prepared from [35S]methionine-labeled human epithelial carcinoma cells persistently infected with measles virus were reacted with virus-specific antisera. Microcolumns of staphylococcal protein A linked to Sepharose were used to isolate antigen-antibody complexes that contained few contaminating host polypeptides. Measles virus polypeptides in these complexes could be identified readily on sodium dodecyl sulfate-polyacrylamide gels even when antiserum with low reactivity toward the viral antigens was used.