title: I-Kk and H-2Kk antigens are shed as supramolecular particles in association with membrane lipids.
abstract: The form of 125I-labeled membrane alloantigens (I-Ak and H-2Kk) and immunoglobulin M shed by murine splenic lymphocytes labeled by lactoperoxidase-catalyzed radioiodination was determined by gel chromatography and ultracentrifugation. I-Ak and H-2Kk antigens are shed as particles ranging in size from 3 X 10(5) to 2 X 10(6), whereas membrane IgM is shed as an individual unit consonant with its native size of 180,000. The effects of detergents on the size of shed I-Ak and H-2Kk and the coprecipitation of (3H) lipids with these proteins suggest that I-Ak and H-2Kk are shed in association with local membrane lipids as small membrane-derived vesicles, whereas membrane IgM is shed without detectable associated lipid.
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D002919:Chymotrypsinogen / Q000494:pharmacology; D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G; D046911:Macromolecular Substances; D008563:Membrane Lipids; D051379:Mice; D008808:Mice, Inbred CBA; D008970:Molecular Weight; D010047:Ovalbumin / Q000276:immunology; D014461:Ultracentrifugation
chemical_list: D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G; D046911:Macromolecular Substances; D008563:Membrane Lipids; D010047:Ovalbumin; D002919:Chymotrypsinogen