Modulation of human T lymphocyte rosette formation by autonomic agonists and cyclic nucleotides

Abstract

Early rosette formation by T lymphocytes appears to be modulated by cyclic nucleotides. Dibutyryl cyclic 3′,5′ adenosine monophosphate (cyclic AMP) 10 −2 M inhibited E rosette formation up to 83%, while 10 −6 M 8-bromo-cyclic guanosine monophosphate (cyclic GMP) increased rosette formation maximally to 67.4% with less pronounced effect at increased concentrations. T lymphocyte receptors for beta adrenergic, alpha adrenergic, and muscarinic cholinergic agonists appear to influence rosette formation. Isoproterenol 10 −2 M induced 67.3% inhibition, while phenylephrine 10 −5 M and carbamylcholine 10 −4 M were associated with enhanced rosette formation of 67.2% and 57.8%, respectively. Selective blockade with propranolol, phentolamine, and atropine indicated the presence of separate receptor sites. The lack of effect of histamine at concentrations of 10 −3 M and above suggests the absence of specific receptors on peripheral human T lymphocytes.