Modulation of histamine type II receptors on CD8+ T cells by interleukin-2 and cimetidine.
CD8+ T cells are known to play a major role in regulating immune functions under normal and disease conditions. In this study a radioligand binding assay was used to quantitate histamine type II (H2) receptors on activated T cells. The objective was to examine the expression of H2 receptors on T cells during activation with interleukin-2 (IL-2) and treatment with cimetidine. Activated suppressor T cells induced by concanavalin A+IL-2 showed a significant (p less than 0.01) increase in H2 receptors compared to the control nonactivated T cells. The T cells expressing the H2 receptors were identified as CD8+ cells; those among them that had an enhanced level of H2 receptors were identified as CD25+. Treatment of activated suppressor cells with the H2 receptor antagonist cimetidine at a concentration of 10(-5) M significantly reduced the number of H2 receptors. Suppressor cells induced by Con A+IL-2 were able to suppress both IgG and IgM production that was reversible with cimetidine. Incubation of lymphocytes with 50 U/ml IL-2 alone in 3-day culture significantly (p less than 0.005) enhanced H2 receptor expression. These studies demonstrate that activated suppressor T cells that are CD8+CD25+ have enhanced levels of H2 receptors and can be modulated by cimetidine.
Shibata
M
M
John Wayne Institute for Cancer Treatment and Research, Santa Monica, CA 90404.
Hoon
D
D
Okun
E
E
Morton
D
D
D000917:Antibody Formation / Q000187:drug effects; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D002927:Cimetidine / Q000494:pharmacology*; D003208:Concanavalin A; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D015375:Receptors, Interleukin-2 / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000737:chemistry; D050378:T-Lymphocytes, Regulatory / Q000737:chemistry / Q000187:drug effects*
D016827:CD8 Antigens; D007376:Interleukin-2; D011970:Receptors, Histamine H2; D015375:Receptors, Interleukin-2; D003208:Concanavalin A; D002927:Cimetidine