Apoptotic human lymphocytes have diminished CD4 and CD8 receptor expression

We used quantitative multiparameter how cytometric assays to simultaneously detect viable, apoptotic, and necrotic human peripheral blood mononuclear cells (PBMC) and immunophenotyped lymphocyte subsets within the PBMC. Apopt osis was induced by a spectrum of treatments, including camptothecin, cispl atin, dexamethasone, hyperthermia, staurosporine, and etoposide in anti-CD3 mAb-stimulated cells and by cyclohexamide in both quiescent and stimulated cells; apoptosis in the latter was augmented by anti-fas mAb. We found tha t CD4(+) and CD8(+) cells were significantly underrepresented in the apopto tic PBMC and that the percentage of CD4(+) and CD8(+) PBMC each markedly de creased as apoptosis increased. This suggested that surface expression of t hese receptors was lessened on apoptotic CD4(+) and CD8(+) cells. This was directly confirmed by observation of sorted CD4(+) PBMC. This analysis of a wide variety of apoptotic stimuli demonstrates that diminished CD4(+) and CD8 surface receptor expression is a common feature of human T lymphocyte a poptosis. (C) 1999 Academic Press.