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pubmed:abstractText |
Activation, anergy, and apoptosis are all possible outcomes of T cell receptor (TCR) engagement. The first leads to proliferation and effector function, whereas the others can lead to partial or complete immunological tolerance. Structural variants of immunizing peptide-major histocompatibility complex molecule ligands that induce selective lymphokine secretion or anergy in mature T cells in association with altered intracellular signaling events have been described. Here we describe altered ligands for mature mouse CD4(+) T helper 1 cells that lead to T cell apoptosis by the selective expression of Fas ligand (FasL) and tumor necrosis factor (TNF) without concomitant IL-2, IL-3, or interferon gamma production. All ligands that stimulated cell death were found to induce FasL and TNF mRNA expression and TCR aggregation ("capping") at the cell surface, but did not elicit a common pattern of tyrosine phosphorylation of the TCR-associated signal transduction chains. Thus, TCR ligands that uniquely trigger T cell apoptosis without inducing cytokines that are normally associated with activation can be identified.
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pubmed:affiliation |
Molecular Development of the Immune System Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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