A SPECIFIC INTERCELLULAR PATHWAY OF APOPTOTIC CELL-DEATH IS DEFECTIVE IN THE MATURE PERIPHERAL T-CELLS OF AUTOIMMUNE LPR AND GLD MICE

Homozygosity for either of the unlinked murine autosomal recessive mutations Ipl or gld leads to autoimmunity characterized by peripheral accumulation of CD4(-)/CD8(-) ''double-negative'' T cells, autoantibodies and various forms of tissue pathology. Recently, the gene affected by lpr was identified as fas, whose product acts as a trigger for programmed cell death or apoptosis. Data reported here indicate that the Fas receptor and its ligand, the wild-type form of the gld gene product, are essential for antigen-stimulated peripheral T cell apoptosis. Furthermore, the wild-type gld gene product is a non-cell-autonomous protein that is produced by activated T cells. Apoptotic elimination of antigen-receptor-triggered peripheral T cells appears to be abnormal in Epr and gld mice, and this deficiency causes peripheral T cells to accumulate resulting in lymphadenopathy. These findings support the importance of apoptotic regulation of lymphocyte persistence after antigen encounter in vivo.