Electrophoretic analysis of polypeptides immune precipitated from cytomegalovirus-infected cell extracts by human sera.
Serodiagnosis of cytomegalovirus (CMV) infection by complement fixation tests depends on showing a fourfold rise in antibody titer from acute- to convalescent-phase sera. Freeze-thaw and glycine-extracted, infected cell culture antigens used for these tests give markedly different titers in reactions with the same sera. In this study, we characterized the CMV-infected cell polypeptides contained in freeze-thaw and glycine-extracted antigens and identified the proteins precipitated by 23 pairs of human acute and convalescent sera. Our results were as follows. First, freeze-thaw and glycine-extracted antigens prepared from infected cells radiolabeled with [35S]methionine and subjected to electrophoresis in sodium dodecyl sulfate-polyacrylamide gels yielded similar patterns, and the bulk of the label was contained in late structural proteins and glycoproteins. Glycine-extracted preparations contained a greater proportion of soluble 66,000- and 50,000-molecular-weight proteins than did freeze-thaw antigens. Second, convalescent sera precipitated proteins migrating with apparent molecular weights of 150,000, 130,000, 110,000, 96,000, 74,000, 66,000, 50,000, 34,000, 32,000, and 25,000. Of these the 130,000-, 110,000-, 96,000-, 66,000-, 50,000-, and 25,000-molecular-weight proteins comigrated with glucosamine-labeled polypeptides. Both immunoglobulin G and M antibodies in human sera precipitated these proteins from CMV-infected cell preparations. Implications of the results for serodiagnosis of CMV infections are discussed.
D000914:Antibodies, Viral; D000956:Antigens, Viral / Q000032:analysis*; D003587:Cytomegalovirus / Q000032:analysis* / Q000276:immunology; D003586:Cytomegalovirus Infections / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D008970:Molecular Weight; D014764:Viral Proteins / Q000032:analysis / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D006023:Glycoproteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D014764:Viral Proteins