Abstract
Effect of AA861, a 5-lipoxygenase inhibitor of arachidonic acid, on natural killer activity in rat whole spleen cells (WSC-NK activity) or rat non-adherent spleen cells (NASC-NK activity) was examined. AA861 significantly depressed WSC-NK activity. On the contrary AA861 showed no inhibitory effect on NASC-NK activity. The depressed WSC-NK activity by AA861 was partly recovered by exogenously added leukotriene B4 (LTB4) in a dose dependent manner, with a significant recovering effect at 10-10 M of LTB4. Then we compared the capacity of LTB4 production between WSC and NASC when stimulated with calcium ionophore A23187. WSC produced a significant amount of LTB4, howevr, NASC produced only a negligible amount of LTB4. We detected LTB4 in the assay medium of WSC-NK activity and the amount of LTB4 in the medium was decreasd by AA861 in a dose dependent manner. The current results may indicate that the inhibitory effect of AA861 on WSC-NK activity is partly mediated by the inhibitory effect of AA861 on LTB4 production in rat spleen adherent cells.
