Cytotoxic activity of human lymphocyte plasma membranes.

Plasma membrane fractions isolated from normal human peripheral blood lymphocytes have considerable cytolytic activity towards a cultured human lymphoblast cell line and mouse mastocytoma cells. Other subcellular fractions, including lysosomes, have low cytolytic activity. It is suggested that this cytotoxic potential in lymphocyte plasma membranes is normally latent but can be activated by prolonged and intimate contact with target cell plasma membranes.