Human lymphokine-activated killer cells suppress pokeweed mitogen-induced immunoglobulin synthesis

Abstract

The effect of human lymphokine-activated killer (LAK) cells on pokeweed mitogen (PWM) induced immunoglobulin synthesis by autologous peripheral blood mononuclear cells (PBMC) was studied. LAK cells induced by the in vitro culture with recombinant human interleukin-2 (IL-2) lysed PWM-activated autologous T cells and B cells, but did not lyse unstimulated lymphocytes. These effector cells which are capable of killing lymphoblasts were shown to express either CD16 surface markers. When CD8(+)-and CD16(+)-enriched cells isolated from the culture with IL-2 were added to cultures containing autologous PBMC and PWM, marked suppression of the IgG production was observed. In contrast, the control CD8(+)-and CD16(+)-enriched cells isolated from the culture without IL-2 showed a weak suppressive effect on PWM-induced IgG synthesis. These results suggest that LAK cells suppress immunoglobulin synthesis by the cytotoxic elimination of activated T cells and B cells.