Short-term lymphokine stimulation of human peripheral blood mononuclear cells generates cytolytic activity against endothelial cells: involvement of natural killer cells.

UNLABELLED: We previously reported that incubation of human peripheral blood mononuclear cells (PBMC) for 5 days with T-cell growth factor (TCGF) resulted in lymphokine-activated killer activity against endothelial cells (EC). In this paper we report on the effects of short-term incubation of PBMC with lymphokines. We show that incubation of PBMC with lymphokines during an 18-hr period is sufficient to generate a strong cytolytic response against EC. The cytolytic capacity of the effector cells was directly dependent on the dose of lymphokine added during the induction phase. When PBMC were separated into adherent and non-adherent cells, the non-adherent fraction could be induced to lytic activity against EC, whereas the adherent cells could not. When PBMC were separated, using 2-amino-ethylisothiouronium bromide hydrobromide-treated sheep red blood cells (AET-SRBC), into T- and non-T-cell fractions, the latter fraction could be induced to lyse EC. TCGF-induced cell-mediated EC lysis could not be inhibited using anti-T3 nor anti-LFA-1 antibodies. Lysis of EC by TCGF-stimulated effector cells was strongly inhibited by the addition of unlabelled K562 target cells, whereas cold OKT3 hybridoma cells did not exert such an effect. IN
CONCLUSION: the kinetics of the induction of lytic activity against EC, as well as the cell separation experiments, suggest that short-term-activated NK cells may lyse EC. This hypothesis was confirmed using monoclonal antibody and cold target cell analysis.