Studies on the maturation of thymus stem cells The effects of catecholamines, histamine and peptide hormones on the expression of T cell alloantigens

Abstract

Studies have been performed in order to investigate the effects of catecholamines, histamine, peptide hormones and various other agents known to increase cellular adenosine 3′:5′-cyclic monophosphate (cAMP) levels, on the expression of Thy-1 and TL antigens on 14-day fetal thymic stem cells. It has been shown that the proportions of Thy-1 and TL positive cells, as detected by dye exclusion cytotoxicity tests, can be significantly increased by some of these agents and that these effects may be inhibited by β adrenergic and H2 antagonists. The value of these tests as a means for studying normal thymic stem cell maturation and for investigating T cell deficiency is discussed.