title: Prostaglandins modulate macrophage Ia expression.
abstract: Prostaglandins are important modulators of inflammation and of humoral and cellular immune responses. In order to evaluate a possible mechanism for the regulation of immune responses we have studied the effects of prostaglandins on the expression of I-region-associated (Ia) antigens by macrophages. The expression of these glycoproteins is essential for macrophages to function as antigen-presenting cells during the induction of immune responses. The synthesis and membrane expression of Ia, however, is not a constitutive property of the phagocyte but is under regulation and a positive regulation of this process is exhibited by activated T cells. In contrast, a negative regulation is conspicuously found in the neonate where a product from a young replicating macrophage inhibits the expression of Ia by the mature macrophages. We show here that prostaglandins of the E series (PGE) are potent inhibitors of the expression of Ia-antigens on macrophages and that thromboxane B2 (TXB2) antagonizes the effect of PGE.
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis*; D008088:Listeriosis / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D011453:Prostaglandins / Q000502:physiology*; D011458:Prostaglandins E / Q000494:pharmacology; D013928:Thromboxane A2 / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000949:Histocompatibility Antigens Class II; D011453:Prostaglandins; D011458:Prostaglandins E; D013928:Thromboxane A2; D003994:Bucladesine