Regulation of human immunoglobulin production in vitro by prostaglandin E2

Human peripheral blood mononuclear cells (HPBMC) from healthy individuals were stimulated polyclonally with pokeweed mitogen (PWM), in vitro, to produce IgG and IgM, which were subsequently measured by enzyme linked immunosorbent assay (ELISA). Indomethacin at 10(-6)-10(-8)M inhibited both IgG and IgM production but only when added within the first 24 hr of culture. PWM-stimulated HPBMC produced prostaglandin E2 (PGE2) during the first 24 hr of culture and this was completely inhibited by 10(-6)M indomethacin. Exogenous PGE2 added to PWM-stimulated HPBMC produced variable effects on immunoglobulin production at relatively high concentration (10(-6)-10(-7)M). However, reversal of inhibition of IgG production caused by 10(-7)M indomethacin was achieved with approximately 10(-7)M PGE2 but indomethacin-mediated inhibition of IgM production could not be fully reversed. No effect of either PGE2 or indomethacin could be detected on the PWM-induced proliferative response. These results suggest that prostaglandin E2, possibly with other arachidonic acid products, may be involved in the regulation of immunoglobulin production.