Inhibition of interleukin 2 production by prostaglandin E 2 is not absolute but depends on the strength of the stimulating signal

Abstract

In view of the eminently important role of interleukin-2 (IL-2) in T-cell responses, and in view of reports about immune stimulatory effects of PGE 2, we reinvestigated the question whether PGE 2 inhibits IL-2 production. It was found that PGE 2 does not inhibit IL-2 production in murine spleen cell cultures after optimal stimulation (5 μg/ml concanavalin A) but does inhibit at suboptimal stimulation conditions. The failure of PGE 2 to inhibit IL-2 production at optimal concanavalin A concentration was demonstrated by two independent IL-2 assays namely by the co-stimulator assay and by the proliferation of IL-2-dependent T-cell clone W-2. Our observations indicated that the inhibitory effect of PGE 2 depends on the strength of the stimulating signal. IL-2 production in cultures with 5 μg/ml concanavalin A was also not suppressed by PGE 1, by prostaglandin D 2, thromboxane B 2 (T × B 2), and prostaglandin F 2.