title: Immunoregulatory functions of paf-acether. II. Decrease of CD2 and CD3 antigen expression.
abstract: Paf-acether (platelet-activating factor) is a phospholipid initially described as a potent platelet-aggregating compound. It is produced by numerous cell types and is now considered as an important mediator of cell-cell interactions. The effect of paf-acether on the expression of CD2 and CD3, two human T cell surface glycoproteins, was investigated by indirect immunofluorescence and flow cytometry. Paf-acether partially down-regulated, in a time- and dose-dependent manner, CD2 and CD3 but not HLA class I antigen expression on peripheral human T cells and Jurkat cells. Lysophosphatidylcholine, a phospholipid closely related to paf-acether, had no detectable modulatory effect on CD2 and CD3 expression. In addition to CD2/CD3 modulation, paf-acether markedly inhibited T cell proliferative response not only to phytohemagglutinin or concanavalin A but also to anti-CD3 or a stimulatory combination of anti-CD2 monoclonal antibodies. These data demonstrate for the first time that lipid mediators such as paf-acether might be involved in the regulation of the expression of cell surface glycoproteins that are essential in the execution of T cell function.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000276:immunology; D018801:CD2 Antigens; D017252:CD3 Complex; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D003864:Depression, Chemical; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000096:biosynthesis* / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D017252:CD3 Complex; D002352:Carrier Proteins; D008244:Lysophosphatidylcholines; D010835:Phytohemagglutinins; D010972:Platelet Activating Factor; D011971:Receptors, Immunologic; D003208:Concanavalin A