title: Prostaglandin E2 inhibits human T-cell proliferation after crosslinking of the CD3-Ti complex by directly affecting T cells at an early step of the activation process.
abstract: We have studied the effects of prostaglandin E2 (PGE2) on in vitro human T-cell activation induced by crosslinking of the CD3-Ti complex with the monoclonal anti-CD3 antibodies OKT3 and UCHT-1. PGE2 (greater than or equal to 3 X 10(-9) M) when added simultaneously with anti-CD3 to cultures of peripheral blood mononuclear cells (PBMC), significantly suppressed, in a dose-dependent way, T-cell proliferation (P less than 0.002). However, when T cells were first preactivated with OKT3 for 3 days, subsequent proliferation driven by recombinant interleukin 2 (IL-2) was not inhibited by addition of PGE2. This indicates that PGE2 affects the activation step resulting from crosslinking of CD3-Ti, but not the IL-2-driven proliferative phase. Other manifestations of T-cell activation were therefore examined. Both IL-2 production and the expression of receptors for IL-2 (as detected with the anti-Tac monoclonal antibody) were inhibited by PGE2. The addition of purified interleukin 1 (IL-1) or recombinant IL-2 to the cultures did not reverse the inhibiting effect of PGE2 on IL-2-receptor expression. PGE2, added at the time of culture initiation, also inhibited T-cell proliferation in cultures which were supplemented with exogenous IL-1 or IL-2. Proof for a direct effect of PGE2 on T cells was obtained in experiments in which monocyte-depleted T cells were stimulated, in the presence of IL-1, with solid-phase-bound anti-CD3 antibody. Proliferation of T cells in this system is accessory cell independent and still was strongly inhibited by PGE2. Finally, preincubation of PBMC with PGE2 (3 X 10(-6) M) for 48 hr did not result in the generation of suppressor cells for anti-CD3-induced T-cell proliferation or for IL-2 production. Our results demonstrate that PGE2 has a direct inhibitory effect on an early step of T-cell activation, resulting in decreased IL-2 production, decreased IL-2-receptor expression, decreased responsiveness to exogenous IL-2, and decreased proliferation. However, PGE2 does not affect IL-2-driven proliferation of activated T cells. The inhibitory effect on T-cell activation is not mediated through suppressor T cells, nor through inhibition of accessory cell function.
mesh_terms: D000328:Adult; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D015232:Dinoprostone; D005260:Female; D006801:Humans; D007375:Interleukin-1; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D011458:Prostaglandins E / Q000096:biosynthesis / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects; D013936:Thymidine / Q000378:metabolism
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007375:Interleukin-1; D007376:Interleukin-2; D011458:Prostaglandins E; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D015232:Dinoprostone; D013936:Thymidine