The effect of the major mediators of type I hypersensitivity on lymphocytes from normal and atopic subjects

Abstract The effects of some of the major mediators of the Type I reaction, (histamine, SRS-A, PGE 2 and PGF 2α ) were investigated in vitro on lymphocytes from normal and atopic individuals. Specific H 1 and H 2 agonists were also examined. Both PGE 2 and histamine suppressed lymphocyte transformation, induced by concanavalin A, atopic being more sensitive to histamine induced suppression of lymphocyte transformation than normals. This differences was obvious at low levels of mitogen stimulation. The effect of histamine appeared to be mediated via the receptor characterised specific H 2 agonists although specific antagonists did not significantly reverse the effect. PGF 2α and high concentrations of the specific H 1 agonist 2-methyl histamine enhanced lymphocyte transformation in atopics but either had no effect or slightly suppressed function in normals.