Identification of the T cell surface signal-transducing glycoprotein sgp-60 as CD48, a counter-receptor for mouse CD2.
We recently showed that CD48 is the major counter-receptor for CD2 in the murine system. To examine whether sgp-60, which has been proposed as the murine homologue of human LFA-3, is another ligand for mouse CD2, we performed the characterization of sgp-60 by using mouse CD2-human IgG chimeric protein (mCD2Rg) and anti-mouse monoclonal antibodies (mAb). Anti-sgp-60 mAb 5-8A10, as well as anti-mouse CD48 mAb HM48-1 completely inhibited the binding of mCD2Rg at the ligand site. 5-8A10 immunoprecipitated the same molecule as that recognized by HM48-1 and reacted with mouse CD48 cDNA-transfected chinese hamster ovary cells, indicating that sgp-60, recognized by 5-8A10, is identical to mouse CD48. The epitope recognized by 5-8A10 was different from that recognized by HM48-1 and OX78, suggesting that the different T cell activating property of these anti-mouse CD48 mAb depends on the epitopes they recognize. The identification of sgp-60 as CD48 further suggests a role of CD48 in regulating T cell activation.
Kato
K
K
Department of Immunology, Juntendo University School of Medicine, Tokyo, Japan.
Tamura
N
N
Okumura
K
K
Yagita
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D001667:Binding, Competitive; D018801:CD2 Antigens; D000071178:CD48 Antigen; D000939:Epitopes; D007158:Immunologic Techniques; D008024:Ligands; D008213:Lymphocyte Activation; D051379:Mice; D011971:Receptors, Immunologic / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D000071178:CD48 Antigen; C000604065:CD48 protein, human; C000604066:Cd48 protein, mouse; D000939:Epitopes; D008024:Ligands; D011971:Receptors, Immunologic