Purified lymphocyte function-associated antigen 3 binds to CD2 and mediates T lymphocyte adhesion.
CD2 is a T lymphocyte glycoprotein that functions in adhesion of T lymphocytes and also as a putative receptor for activation signals. Functional data suggest that LFA-3, a widely distributed cell surface glycoprotein, may be the biological ligand of CD2. We have purified LFA-3 from human erythrocytes and characterized the purified protein functionally. LFA-3 bound specifically to CD2+ cells, and this binding was inhibited by CD2 mAb. Conversely, purified LFA-3 inhibited binding of CD2 mAb to cells, and the concentration required for this effect suggests that LFA-3 half-saturated CD2 at 1-5 nM LFA-3. Purified LFA-3 inhibited rosetting of human and sheep erythrocytes with CD2+ T lymphoma cells and T lymphocytes, and mediated aggregation of a CD2+ T lymphoma cell line. Purified LFA-3 reconstituted into planar membranes mediated efficient CD2-dependent adhesion of T lymphoblasts. These data demonstrate that LFA-3 is a ligand for CD2 and that LFA-3 can mediate T lymphocyte adhesion.
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology* / Q000302:isolation & purification; D001402:B-Lymphocytes / Q000276:immunology; D002448:Cell Adhesion; D002462:Cell Membrane / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000276:immunology; D008081:Liposomes / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1; D051379:Mice; D012756:Sheep; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D008081:Liposomes; D016169:Lymphocyte Function-Associated Antigen-1