Characterization of the antigens recognized by two monoclonal antibodies reactive with basal-layer keratinocytes of human epidermis.
Two monoclonal antibodies, GR3 and GR4, reactive with the basal-layer keratinocytes of human epidermis, were derived by immunization of Balb/c mice with glycoproteins isolated from cultured keratinocytes by lectin-affinity chromatography. Immunoprecipitation of Triton X-100 extracts from human keratinocytes metabolically labelled with D-[1-14C]glucosamine revealed that GR3 recognized a major glycoprotein with migration properties identical with those of a glycoprotein (reduced form M(r) 126,000) which was previously shown to be implicated in intercellular adhesion [Roberts and Brunt (1985) Biochem J. 232, 67-70]. In their unreduced forms the antigens recognized by GR3 and GR4 both migrated as two bands with M(r) values of 118,000 and 147,000. Comparison of 125I-labelled glycoproteins immunoprecipitated by GR3, GR4 and integrin antibodies revealed that, under reducing conditions, the major band immunoprecipitated by both GR3 and GR4 co-migrated with the alpha 3 and beta 1 integrin chains. In addition the immunoprecipitate obtained with GR4 contained an additional band co-migrating with the alpha 2 integrin chain. Sequential immunoprecipitation studies with GR3, GR4 and integrin antibodies confirmed that GR3 is directed against the alpha 3 integrin chain, whereas GR4 is directed against the beta 1 chain. These studies also indicate that some of the alpha 2 integrin chains on keratinocytes may be associated with a beta-chain not recognized by the antisera against the beta 1 integrin chain used in this study.
Roberts
G P
GP
Department of Dermatology, University of Wales College of Medicine, Cardiff, U.K.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000032:analysis* / Q000276:immunology; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000078404:Epidermal Cells; D004817:Epidermis / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D015603:Keratinocytes / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011233:Precipitin Tests
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D008562:Membrane Glycoproteins