This cross-talk leads to stimulation of β-ARs on mononuclear cells, which inhibits T-cell proliferation, decreases cytotoxic-T-cell and natural killer cell activity, and regulates immune cell maturation and lymphocyte homing ( 3– 5). Growing evidence suggests that the sympathetic nervous system interacts with the immune system through the neurotransmitters norepinephrine and epinephrine that are released from noradrenergic nerve endings in primary and secondary lymphoid organs. Β-ARs, particularly β 2-ARs, are expressed on virtually all peripheral blood cells( 2). Stimulation of β-AR activates adenylyl cyclase, resulting in increased intracellular levels of the second messenger cyclic adenosinemonophosphate (cAMP) that signals via cAMP-dependent protein kinase A (PKA) to orchestrate downstream intracellular events ( 1). Three subgroups of β-ARs- β 1, β 2, and β 3-are distinguished based on differences in interactions with agonists. These data show that flow cytometric quantification of relative β-AR expression in circulating leukocytes is a suitable technology for large-scale clinical application.ī eta -adrenergic receptors ( β-ARs) belong to a family of transmembrane G-protein coupled proteins that are physiologically activated by epinephrine and norepinephrine. β-AR expression was significantly higher in granulocytes compared to mononuclear cells. Testing of three different standard cell fixation and permeabilization methods (formaldehyde fixation and saponin, Tween-20, or Triton-X 100 permeabilization) showed that the formalde-hyde/Triton-X 100 method yielded the best results.

The probe was chemically modified by adding a spacer moiety between biotin and alprenolol to stabilize receptor binding, thus preventing binding decay. Quantum™ MESF beads were used for quantification in absolute fluorescence units. Here, we report optimization of a flow cytometry-based method utilizing a biotinylated β-AR ligand alprenolol as a probe and use of this method to quantify relative receptor expression in healthy controls (HC).

Classical methods for β-AR quantification are based on labor-intensive and time-consuming radioligand binding assays. Quantification of β-AR density may have clinical implications in terms of assessing disease severity and identifying patients who could potentially benefit from beta-blocker therapy. Beta-adrenergic receptors ( β-ARs) play a critical role in many diseases.

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