Lack of effect of LTB4 on human natural killer cell activity and T lymphocyte transformation

Human natural killer (NK) cell activity was not significantly affected by leukotriene (LT) B4 over a wide concentration range (10(-6)-10(-14) M), whether added directly to the NK cell assay or after preincubation of effector cells for 2 h with the drug before addition of Cr labelled K562 target cells. In addition, LTB4 did not affect the kinetics of NK cell mediated cytotoxicity. Addition of LTB4 (10(-6)-10(-10) M) to concanavalin A (Con A) or phytohaemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PBMC) had no significant effect on proliferation measured by tritiated thymidine incorporation, using both optimal and sub-optimal mitogen concentrations. Whilst it is clear that LTB4 is an important mediator of inflammation involving polymorphonuclear (PMN) leukocytes in vivo, it does not affect NK cell or T cell function in vitro.