ABNORMAL EARLY TCR CD3-MEDIATED SIGNALING EVENTS OF A SNRNP-AUTOREACTIVE LUPUS T-CELL CLONE/

Multiple immunoregulatory abnormalities characterize systemic lupus er ythematosus. Abnormalities of the antigen receptor-mediated early sign al transduction biochemical events underscore the diverse cellular abe rrations. Fresh peripheral T and B cells and T cell lines from patient s with systemic lupus erythematosus display increased Ca2+ responses t hat are preceded by enhanced antigen receptor-initiated cytosolic prot ein tyrosine phosphorylation. To further dissect the aberrant signalin g events of lupus T cells we studied the early anti-CD3 mAb-induced si gnaling events in autoantigen-specific T cells from lupus patients. We report herein that a lupus snRNP-specific T cell clone, but not other T cells, displays increased Ca2+ fluxes and enhanced production of ty rosine-phosphorylated proteins following TCR/CD3 stimulation.