Physiology of IgD. VII. Induction of receptors for IgD on cloned T cells by IgD and interleukin 2.
The role of IgD in the immune response has remained elusive, although the predominance of IgD on the B cell surface and the paucity of IgD in serum have suggested a receptor function. In support of this hypothesis, it has recently been shown that receptors for IgD on helper T cells can be induced by exposure to IgD in vivo and in vitro. Such IgD receptor-positive T cells (i.e., T delta cells), detectable as RFC using IgD-coated SRBC, augment antibody responses. In this report, we demonstrate that cloned, antigen-specific T cells of helper phenotype show only very low percentages of IgD-RFC, if allowed to rest in vitro after antigen exposure in the absence of IL 2. Exposure to IgD or to IL 2 for 24 hr causes the IgD-specific RFC to increase as much as 25-fold to nearly 80%. Clones that have recently been stimulated with antigen, or T cell hybridomas prepared from such clones, exhibit 40 to 50% IgD-RFC before exposure and twofold higher levels after exposure to IgD. IL 2 also causes a dose-dependent induction of OgD-RFC in normal splenic T cells. Thus, antigen stimulation, IL 2 and IgD can all induce these receptors for IgD which presumably enable helper T cells to interact more effectively with IgD+ B cells.
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis; D002478:Cells, Cultured; D006825:Hybridomas / Q000276:immunology; D007072:Immunoglobulin D / Q000502:physiology*; D007376:Interleukin-2 / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011961:Receptors, Fc; D011971:Receptors, Immunologic / Q000378:metabolism*; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007072:Immunoglobulin D; D007376:Interleukin-2; D011961:Receptors, Fc; D011971:Receptors, Immunologic; C050855:immunoglobulin D receptor