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

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. Isoproternol 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 recepotrs on peripheral human T lymphocytes.