Functional characteristics of histamine receptor-bearing mononuclear cells. I. Selective production of lymphocyte chemoattractant lymphokines with histamine used as a ligand

Abstract

Mitogens and antigens have been the traditional ligands for activating lymphocytes in vitro for the elaboration of lymphokines. Recently, histamine, by interaction with histamine-type 2 receptors on T lymphocytes, has been found to induce the production of one lymphokine, histamine-induced suppressor factor (HSF), that inhibits lymphocyte proliferation and lymphokine production in vitro. Because the biologic effects of HSF appear to be confined to alterations in lymphocyte function, we assessed the ability of soluble products of histamine-stimulated human blood mononuclear cells to affect another lymphocyte function, motility. Utilizing a modified Boyden chamber assay to assess lymphocyte migration, we identified chemoattractant activity for human blood and rat splenic T lymphocytes in histamine-induced mononuclear cell supernatants. No neutrophil or monocyte chemoattractant activity was present. Sephadex G-100 gel filtration of histamine-induced supernatants showed the lymphotactic activity eluted with a 56,000 m.w. This activity was cationic as determined by its elution pattern from a Sephadex QAE anion exchange matrix with a single pl of 9.0 to 9.4 determined by isoelectric focusing in sucrose. Its biologic activity is predominantly chemokinetic in nature, is stable to heating at 56 degrees C for 30 min, but is sensitive to the effects of trypsin and neuraminidase. These physicochemical and functional characteristics establish it as identical to a recently described concanavalin A-induced (Con A) lymphotactic lymphokine (LCF). Mononuclear cells that did not adhere to a histamine affinity matrix were unable to produce LCF when subsequently stimulated with histamine or Con A. Mononuclear cells incubated with histamine and diphenhydramine produced LCF; the addition of cimetidine eliminated LCF production. In fact, supernatants from cells incubated with histamine and cimetidine significantly inhibited lymphocyte migration, a phenomenon explainable by the two regions of lymphocyte migration inhibitory activity that were present in the Sephadex G-100 chromatography of crude histamine-induced supernatants. These data suggest that a subset of lymphocytes defined by the presence of histamine-type 2 receptors is capable of producing LCF while cells that bear histamine-type 1 receptors produce lymphocyte migration inhibitory activity.