Klokker, M., N. H. Secher, P. Madsen, M. Pedersen, and B. K. Pedersen. Adrenergic β1- and β1+2-receptor blockade suppress the natural killer cell response to head-up tilt in humans. J. Appl. Physiol. 83(5): 1492–1498, 1997.—To evaluate stress-induced changes in blood leukocytes with emphasis on the natural killer (NK) cells, eight male volunteers were followed during three trials of head-up tilt with adrenergic β1- (metoprolol) and β1+2- (propranolol) blockade and with saline (control) infusions. The β1- and β1+2-receptor blockade did not affect the appearance of presyncopal symptoms, but the head-up tilt induced a transient lymphocytosis that was abolished by β1+2-receptor blockade but not by β1-receptor blockade. Head-up tilt also resulted in delayed neutrophilia, which was insensitive to β-receptor blockade. Lymphocyte subset analysis revealed that the head-up tilt resulted in a twofold increase in the percentage and absolute number of CD3−/CD16+and CD3−/CD56+NK cells in peripheral blood and that this increase was partially blocked by metoprolol and abolished by propranolol. The NK cell activity on a per NK cell basis did not change during head-up tilt, indicating that the cytotoxic capability of NK cells recruited to circulation is unchanged. The data suggest that the head-up tilt-induced lymphocytosis was due mainly to CD16+and CD56+NK cells and that their recruitment to the blood was inhibited by β1- and especially β1+2-receptor blockade. Thus stress-induced recruitment of lymphocytes, and of NK cells in particular, is mediated by epinephrine through activation of β-receptors on the lymphocytes.
Hierarchy of the Human Natural Killer Cell Response Is Determined by Class and Quantity of Inhibitory Receptors for Self-HLA-B and HLA-C Ligands
