Fas ligand mediates activation-induced cell death in human T lymphocytes.

Abstract

Suml'l'lary A significant proportion of previously activated human T cells undergo apoptosis when triggered through the CD3/T cell receptor complex, a process termed activation-induced cell death (AICD). Ligation of Fas on activated T cells by either Fas antibodies or recombinant human Fas-ligand (Fas-L) also results in cytolysis. We demonstrate that these two pathways of apoptosis are causally related. Stimulation of previously activated T ceils resulted in the expression of Fas-L mILNA and lysis of Fas-positive target cells. Fas-L antagonists inhibited AICD of T cell clones and staphylococcus enterotoxin B (SEB)-specific T cell lines. The data indicate AICD in previously stimulated T ceils is mediated by Fas/Fas-L interactions. Mature peripheral T cells generally undergo activation . and proliferation when stimulated through the CD3/ TCR complex. Under certain circumstances, however, thymocytes, T cell hybridomas, and both CD4 + and CD8 + T cell clones (TCC) 1 undergo cell death when stimulated through the TCR with CD3 antibody in the absence of APC (1-6). This process is rapid and exhibits classic characteristics of apoptosis such as membrane blebbing, chromatin condensation, and the formation of DNA fragments of ",,200 bp. Deletion of T cells by apoptosis appears to be important not only in regulating autoreactive T cells in the thymus, but also in regulating the peripheral T cell pool (7,8). Little is known, however, about the mechanism that mediates the lytic process that has been termed activation-induced cell death (AICD).Fas/APO-1 (CD95) is a protein expressed on the surface of a variety of transformed cell lines and chronically stimulated T cells that can mediate apoptosis after ligation with a Fas-specific antibody (9-12). Under appropriate conditions Fas also transduces a stimulatory signal to certain B cell lines (13) and to .freshly isolated human peripheral blood T cells and thymocytes (14). To investigate a possible relationship between CD3-stimulated AICD and Fas-mediated T cell apoptosis, we have used a mAb directed against human Fas (Fas M3). Immobilized Fas M3 mAb is able to lyse Fas-expressing tumor cell lines in a manner analogous to Fas-ligand (Fas-L) or the prototypic Fas mAb, CH-11, whereas soluble Fas M3 blocks Fas-mediated killing (15).1 Abbreviations used in this paper: AICD, activation-induced cell death; Fas-L, Fas-ligand; SEB, staphylococcal enterotoxin B; TCC, T cell done, Materials and MethodsT Cell Lines and Clones. The alloreactive TCC used in this study were generated by establishing MLC in bulk culture for 7 d followed by limit dilution cloning in 96-well round-bottomed plates in the presence of 10 s irradiated allogeneic PBMC and 10 ng/mt of Ib2. TCC were maintained by stimulation with irradiated PBMC and soluble CD3 antibody (10 ng/ml) approximately every 2 wk and maintenance in IL-2 (10 ng/ml) between stimulations. Shortterm staphylococcal enterotoxin B (SEB)-specific T cell lines were established by stimulation of PBMC (106) with 5 /~g/ml SEB (Sigma Chemical Co., St. Loui...

Enhanced expression of IFN-γ mRNA in CD4+ or CD8+ tumour-infiltrating lymphocytes compared to peripheral lymphocytes in patients with renal cell cancer

“…It may be concluded from the concomitantly high levels of IL-10 mRNA and IFN-γ mRNA in CD8 + TIL that Th1 as well as Th2 lymphocytes are activated, which is in accordance with a recently published study showing also high levels of IL-10 and IFN-γ mRNA in TIL from non-small cell lung cancer and ovarian cancer biopsies (Asselin-Paturel et al, 1998;Pisa et al, 1992). Since it has recently been shown that in vitro activated T cells express high levels of FasL mRNA and protein (Alderson et al, 1995;Brunner et al, 1995;Dhein et al, 1995;Martinez-Lorenzo et al, 1996), the elevated FasL mRNA levels in RCC TIL also indicate an immunological activation of these lymphocytes.…”

Induction of apoptosis and modulation of activation and effector function in T cells by immunosuppressive drugs

“…All other ISD tested did not modulate CD95-sensitivity in Jurkat cells or in peripheral T cells. AICD in Jurkat T cells [45] and peripheral human T cells [46] is mediated mainly by an increased production and release of CD95L. Therefore we hypothesized that ISD might induce an accelerated AICD by increased CD95L production.…”

Modulation of Fas-mediated apoptosis of human thyroid epithelial cells by IgG from patients with Graves' disease (GD) and idiopathic myxoedema

“…Activated T cells in vitro express Fas ligand (FasL), a natural ligand for Fas, and efficiently kill Fas þ target cells [30,31], indicating that the regulation of the interaction of Fas and FasL is important in the development of goitre and hyperthyroidism in patients with GD. Considered together, these results suggest that the goitrogenic activity of TSAb in GD may, in part, be associated with the inhibitory effect on Fas-mediated apoptosis of thyrocytes.…”