Supplementation of male inhibitory material to lipid A activated human mononuclear cell supernatants contributes to the suppression of polymorphonuclear cell phagocytosis

Human normal peripheral blood mononuclear cells were stimulated with lipid A (LA), the biologically active moiety of bacterial lipopolysaccharides. LA-activated supernatants were able to suppress polymorphonuclear cell (PMN) phagocytosis of Candida albicans. This inhibitory activity was enhanced by the supplementation of male inhibitory material (MIM) to active supernatants. The addition of a recombinant human anti-interleukin-1 beta monoclonal antibody to activated supernatants in the absence or presence of MIM diminished or abrogated, respectively, the suppressive effect on PMN function. The mechanisms and the significance of MIM-mediated inhibition of phagocytosis under these circumstances are discussed.