Interaction of CD2 with its ligand lymphocyte function-associated antigen-3 induces adenosine 3',5'-cyclic monophosphate production in T lymphocytes.
CD2 (T11, the T cell E receptor), a nonpolymorphic 47- to 55-kDa glycoprotein, is a T cell-specific surface protein that plays an important role in T lymphocyte adhesion, signal transduction, and differentiation. A natural ligand of CD2 is lymphocyte function associated Ag-3 (LFA-3 (CD58)), a widely expressed glycoprotein of 50 to 70 kDa. The physiologic interaction of CD2 with LFA-3 functions to increase intercellular adhesion and plays a role in T cell activation. This interaction, however, in the absence of other stimuli, has not previously been shown to induce intracellular signals such as Ca2+ mobilization or IL-2 production. To investigate whether cAMP may play a role in ligand-triggered CD2-mediated signal transduction, we have studied the ability of purified LFA-3 and anti-CD2 mAb to induce changes in intracellular cAMP content in murine Ag-specific T cell hybridomas that stably express wild-type and mutated human CD2 molecules. By using a RIA sensitive to the femtomolar range and specific for cAMP, we demonstrate that purified LFA-3, like anti-CD2 mAb, is capable of inducing marked, transient increases in the intracellular concentration of cAMP. Presentation of purified LFA-3, like anti-CD2 mAb, is capable of inducing marked, transient increases in the intracellular concentration of cAMP. Presentation of purified LFA-3 alone to CD2-expressing hybridoma cells, however, did not stimulate phosphatidylinositol turnover nor IL-2 production. The cytoplasmic domain of CD2 is necessary for these ligand-induced cAMP changes, demonstrating that LFA-3 binding to CD2 transduces a signal to the cell. Experiments using the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine showed that CD2-mediated regulation of cAMP levels occurs primarily by the stimulation of cAMP production rather than by the inhibition of cAMP degradation. These results demonstrate that the interaction of LFA-3 with CD2, in the absence of other stimuli, is capable of initiating intracellular biochemical changes and suggest that CD2/LFA-3 interactions may regulate T cell function at least in part through the generation of intracellular cAMP.
Hahn
W C
WC
Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115.
Rosenstein
Y
Y
Burakoff
S J
SJ
Bierer
B E
BE
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology*; D000954:Antigens, Surface / Q000502:physiology*; D018801:CD2 Antigens; D018968:CD58 Antigens; D000242:Cyclic AMP / Q000096:biosynthesis*; D006801:Humans; D006825:Hybridomas; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D007376:Interleukin-2 / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D011971:Receptors, Immunologic / Q000502:physiology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology*; D014162:Transfection
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018801:CD2 Antigens; D018968:CD58 Antigens; D007295:Inositol Phosphates; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D000242:Cyclic AMP