Differential effects of propranolol on lymphocyte rosette formation and response to plant mitogens

The effects of propranolol on various lymphocyte functions were studied to gain a better understanding of the recently demonstrated suppressive effect of propranolol on rheumatoid factor production. D- and L-propranolol at a concentration of 1 X 10(-4)M inhibited the formation of human EA rosettes. The inhibition occurred within one minute of adding the compounds, was reversible, and did not affect cell viability. Addtion of propranolol to preformed EA rosettes failed to disaggregate them. Patching and capping of SIg by an Fab'2 anti-IgG were inhibited at 2.5 X 10(-5)M and above. Propranolol at 2.5 X 10(-5)M also inhibited lymphocyte response to phytohemagglutinin and pokeweed mitogen without evidence of cell toxicity by trypan blue staining or absolute numbers of surviving cells. Congeners of propranolol with mainly beta adrenergic blocking properties did not show inhibitory effects. The inhibitory activities of propranolol are interpreted in terms of propranolol's membrane stablizing effects and ability to interfere with membrane receptor movement.