ACTIVATION-INDUCED EXPRESSION OF HUMAN PROGRAMMED DEATH-1 GENE IN T-LYMPHOCYTES

The Programmed Death-1 (PD-1) gene is a member of the immunoglobulin s uperfamily of genes. Murine PD-1 mRNA expression has been shown to cor relate with activation-induced apoptosis in a mouse T-cell hybridoma c ell line and in murine thymocytes. Here we report that expression of t he human homolog, hPD-1, seems to correlate with activation of T lymph ocytes rather than apoptosis. We observed a time-dependent upregulatio n of hPD-1 mRNA and protein levels in Jurkat cells during phorbol este r (12-O-tetradecanoylphorbol 13-acetate, TPA)-induced differentiation. Human PD-1 protein was also induced during lectin-stimulated activati on of human peripheral blood mononuclear cells. Additionally, TPA stim ulation of Jurkat cells induces tyrosine phosphorylation of hPD-1, put atively on its cytoplasmic tail signal transduction motif, These data suggest a role for hPD-1 during activation and differentiation of T-ly mphocytes. (C) 1997 Academic Press.