Beta-adrenergic receptors on human suppressor, helper, and cytolytic lymphocytes

Using the radioligand beta-adrenergic blocker [ 125I]cyanopindolol (ICYP), we have characterized the beta-adrenergic receptors on Leu 3 + (T helper [T H]), Leu 2 +, 9.3 − (T suppressor [T s]) and Leu 2 +, 9.3 + (T cytolytic [T c]) subsets of human lymphocytes. Peripheral blood T cells were isolated by rosetting, and then subsets were purified by their affinities to monoclonal antibodies against their Leu 3 and 9.3 markers. ICYP binding to the subsets was saturable with time and with concentration; the binding was stereoselective and reversible by beta-adrenergic antagonists. A biological response produced by beta agonists increased intracellular concentrations of cAMP and corresponded to the number of binding sites. Each subset of cells had a number of binding sites, which was characteristic for the given subset. The data indicate that the density of distribution of beta-adrenergic receptors was not homogeneous on the precursors of phenotypically and functionally distinct T cells (T s ~ 2900, T c ~ 1800 and T H ~ 750 binding sites). The displacement studies using beta-adrenergic agonists were performed on the cytolytic and suppressor T cell subsets, suggesting that the receptors were mainly of the beta-2 type. The immunobiological significance of such selective distribution of numbers and subtypes of betaadrenergic receptors on distinct T cell subsets is under investigation.