Suppressive effect of bradykinin to cellular immune responses in vivo and in vitro.

: Bradykinin, as well as histamine, one of the mediators in IgE mediated immediate type allergic reactions or acute inflammation, may affect the in vitro and in vivo cell-mediated immune reactions of the immunized animals. It was demonstrated in our present experiment that the appearance of delayed type hypersensitivity (DTH) skin reaction in the immunized guinea pig was remarkably suppressed by treatment of bradykinin or histamine and the suppression of cutaneous DTH by bradykinin was inhibited by H-2 antagonist (burimamide) but not by H-1 receptor blocker (chlorpheniramine). It was also clearly demonstrated that bradykinin suppressed the production of antigen-induced macrophage migration inhibitory factor (MIF) of the immune guinea pig peritoneal exudate cells (PECs) and the production of MIF was blocked by H-2 antagonist (burimamide) or H-2 agonist (tolazolin) but not by H-1 antagonist (chlorpheniramine). Antigen-induced lymphocyte proliferation of the immunized mice, one of the indicators of the cellular immune response, was also suppressed by treatment of bradykinin. These results indicate that bradykinin as well as histamine may have some role in the subsequent expression of cellular immune reactions.