Interferon-induced Augmentation of Cytotoxic Killer Cell Generation in Mixed Lymphocyte Cultures: Analysis of the Effector Cell Product

Abstract

Alloreactive cytotoxic [human] lymphocytes were generated during mixed lymphocyte cultures (MLC). Human leukocyte interferon added during MLC gave rise to a moderate inhibition of thymidine uptake; augmentation of the allospecific cytotoxic product generated was found. Effector cell activities after MLC in the presence and absence of interferon against autologous cells were negligible; NK[natural killer cell]-sensitive targets and antibody-coated target cells were killed to a higher extent, comparably, by cells generated during MLC in the absence of interferon. Cell separation experiments and cold target inhibition experiments were performed; the effector cells generated with and without interferon had similar characteristics and were distributed among the same lymphocyte subpopulations. The augmented cytotoxicity apparently was caused by alloreactive T cells, most of which were F(c).gamma. receptor-negative, and was not due to enhanced NK-like or antibody-dependent cell-mediated cytotoxic acitivity induced by interferon.