Human Natural Cell‐mediated Cytotoxicity against Fetal Fibroblasts

Abstract

The dependence of human natural killer (NK) cell activity on antibodies [Ab] was investigated. Absorption of the culture medium with target cells, trypsinization of the effector cells followed by a brief recovery and incubation of the effector cells in serum-free nutrient medium did not affect natural killer cell activity against fetal fibroblasts. No soluble mediator in the nutrient media of effector cell-fibroblast co-cultures could be demonstrated. Ab are not involved in the cytolytic activity of natural killer cells. Competition data and the activity of isolated NK cells against Ab-coated target cells suggested overlapping between the effector cells mediating natural and Ab-dependent cell-mediated cytotoxicity.