Three molecular weight forms of natural human interferon-gamma revealed by immunoprecipitation with monoclonal antibody.
Immune interferon (IFN-gamma), endogenously labeled with [35S]methionine, was produced in human peripheral blood lymphocyte cultures stimulated with 12-O-tetradecanoylphorbol-13-acetate and phytohemagglutinin. 35S-IFN-gamma, immunoprecipitated from the crude culture fluid with a monoclonal antibody, was resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into three monomeric forms with molecular weights of 25,000, 20,000, and 15,500, which we designate IFN-gamma I, II, and III, respectively. IFN-gamma I was the most, and IFN-gamma III the least, abundant in both immunoprecipitated 35S-IFN-gamma and chromatographically purified IFN-gamma preparations. Changes in the molecular size of the monomeric forms after glycosidase treatment suggested that IFN-gamma I contains more carbohydrate than IFN-gamma II, and that IFN-gamma III may not be glycosylated at all. Hence, the differences in the carbohydrate contents are likely to be the major cause of the molecular size heterogeneity of IFN-gamma I, II, and III.
D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D006801:Humans; D007371:Interferon-gamma / Q000302:isolation & purification*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D008970:Molecular Weight; D010704:Phorbols / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D010704:Phorbols; D010835:Phytohemagglutinins; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate