Changes in the cholinergic system of lymphocytes due to mitogenic stimulation.

A significant increase in acetylcholinesterase (AChE) activity and muscarinic-type cholinergic receptor (mAChR) expression was demonstrated in normal human peripheral blood lymphocytes as an early response to various stimuli. AChE activity of lymphocytes from T-cell acute lymphoid leukemia patients, and that of leukemic cell lines was enhanced or increased only slightly, in good accordance with their significantly decreased response to mitogenic stimuli. The higher initial AChE activity of cultured leukemic cell lines probably reflects their permanently activated state. AChE activity and mAChR expression in these cases could only be increased by a differentiation-inducing agent. Based on these observations, the possible role of the cholinergic modulation in thymic lymphocyte maturation is assumed.