title: Natural and recombinant Escherichia coli-derived interferon-gamma differ in their reactivity with monoclonal antibody.
abstract: Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), but not Escherichia coli-derived recombinant IFN-gamma. In addition, GIF-1 antibody failed to immunoprecipitate 125I-labeled recombinant IFN-gamma, whereas it precipitated natural IFN-gamma in a concentration-dependent manner. The lack of recognition of recombinant IFN-gamma by antibody GIF-1 may not be due to the absence of the oligosaccharide moiety in the molecules of recombinant IFN-gamma alone, because removal of carbohydrate from natural IFN-gamma by treatment with a mixture of glycosidases did not alter the selective binding of antibody, i.e., deglycosylated and untreated natural IFN-gamma were equally neutralized and immunoprecipitated by GIF-1 antibody. In addition, a minor monomeric component of natural IFN-gamma with the m.w. of 15,500, which apparently lacks carbohydrate, was also recognized by antibody GIF-1. These results suggest that the discriminative recognition of natural and recombinant IFN-gamma by monoclonal antibody GIF-1 may be due to a conformational difference at or near the active regions of natural and recombinant human IFN-gamma molecules.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions / Q000187:drug effects; D001666:Binding Sites, Antibody; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D004927:Escherichia coli Infections / Q000276:immunology*; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests
chemical_list: D000911:Antibodies, Monoclonal; D007371:Interferon-gamma; D006026:Glycoside Hydrolases