Interleukin-2 (IL-2) activated natural killer (A-NK) cells: binding to microvascular endothelial cells and BRM enhancement of cytolytic activity.

A syngeneic in vitro system was developed for investigation of the binding of purified murine interleukin-2 (IL-2) activated natural killer (A-NK) cells to murine microvascular endothelial cells. This system is potentially useful as a model to investigate biochemical and molecular events underlying the binding of A-NK cells to microvascular endothelial cells within metastases in vivo that we have previously noted using electron microscopy. A-NK/endothelial cell binding in the syngeneic system was compared with the binding of allogeneic A-NK cells to the endothelial cells. Among test agents used to pretreat the A-NK cells for modulation of binding, lipopolysaccharide (LPS) most consistently enhanced binding. Additionally, test agents were also used in concurrent assays of A-NK cytolytic activity versus YAC-1 and P815 tumor cell targets. Polyinosinic: polycytidylic acid (poly IC), and gamma interferon (gamma IFN) were among the test agents which enhanced A-NK cell cytolytic activity.