Decay-accelerating factor functions as a signal transducing molecule for human T cells.
Decay-accelerating factor (DAF) is a cell surface protein that protects cells from autologous C-mediated lysis. DAF is one of the first phosphatidylinositol-linked molecules to be described on human T cells. The current studies demonstrate that low levels of DAF are expressed on a majority of freshly isolated human T cells and that DAF expression rapidly increases after T cell activation by mitogens. Moreover, antibodies to DAF induce T cell proliferation when the cells are co-stimulated with phorbol esters. The induction of proliferation is facilitated when the antibodies to DAF cross-linked with a secondary antibody. T cell mitogenesis is largely dependent on the phosphatidylinositol-linked form of DAF, because removal of DAF by a phosphatidylinositol-specific phospholipase C eliminates anti-DAF-induced T cell proliferation. These studies suggest that DAF on the surface of T cells may not only serve to afford protection from autologous C but may also function to transmit signals that induce T cell activation.
Davis
L S
LS
Harold C. Simmons Arthritis Research Center, Southwestern Medical Center, Dallas, TX 75235.
Patel
S S
SS
Atkinson
J P
JP
Lipsky
P E
PE
D000328:Adult; D018958:CD55 Antigens; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008565:Membrane Proteins / Q000097:blood / Q000276:immunology* / Q000302:isolation & purification; D008934:Mitogens; D008970:Molecular Weight; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000494:pharmacology; D011233:Precipitin Tests; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D018958:CD55 Antigens; D007106:Immune Sera; D008565:Membrane Proteins; D008934:Mitogens; D004247:DNA; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase