Priming of normal human neutrophils by recombinant human growth hormone

Abstract

Growth hormone (GH) plays an important role in the development, maintenance and function of the immune system. Previous data has demonstrated that GH is also a newly defined macrophage-activating factor. Activation of polymorphonuclear neutrophils (PMN) by GH has not yet been examined. This paper presents studies demonstrating the effects of GH on the migratory behaviour and respiratory burst of PMN. In a modified Boyden chamber chemotaxis assay, GH did not stimulate PMN locomotion when added directly to the cells but potently inhibited formylpeptide-stimulated chemotaxis with effective concentrations in the picomolar range. The migration inhibition observed is known from studies on PMN priming-factors to be due to enhanced adhesiveness of PMN to artificial surfaces such as nitrocellulose, suggesting that GH stimulates PMN adhesiveness. Priming of PMN by GH was confirmed by direct demonstration of a stimulatory effect on reduction of nitroblue tetrazolium. These findings suggest that GH may be involved in the regulation of PMN functions.

Regulation of Neutrophil Adhesion by Pituitary Growth Hormone Accompanies Tyrosine Phosphorylation of Jak2, p125FAK, and Paxillin

“…It is well established that GH is a physiological mediator of immune cell functions (15)(16)(17)(18)(19), and many of the actions of this stimuli are likely to be transduced through the Jak2 pathway (20,21,23). Although it has been reported that GH increases neutrophil adhesion, the possible mechanisms have not been examined (16).…”

“…GH has been shown to influence the development of the immune organ and the function of immune cells (15)(16)(17)(18)(19). The binding of GH to its receptor causes dimerization of two growth hormone receptor (GHR), which, in turn, initiates the signal transduction in the cell.…”

Priming of polymorphonuclear neutrophils by atrial natriuretic peptide in vitro.

“…From the peripheral blood of healthy volunteers (anticoagulated with EDTA), PMN were obtained after discontinuous density gradient centrifugation of whole blood on Percoll or from buffy coat residues (mixed with normal saline in a ratio of 3:1) by dextran sedimentation and centrifugation through a layer of Ficoll-Hypaque as described (26), followed by hypotonic lysis of contaminating erythrocytes using sodium chloride solution. The cell preparations (> 95% neutrophils by morphology in Giemsa stains, > 99% viable by trypan dye exclusion) were resuspended in RPMI-1640/0.5% BSA forchemotaxis experiments, or in HBSS for respiration burst activity and exocytosis assays.…”

“…NBT reduction by PMN was measured as described (26 Chemotaxis. The chemotactic response of PMN to different gradients of FMLP and/or ANP was tested in a modified multiwell Boyden chamber as previously described (26).…”

“…NBT reduction by PMN was measured as described (26 Chemotaxis. The chemotactic response of PMN to different gradients of FMLP and/or ANP was tested in a modified multiwell Boyden chamber as previously described (26). To the upper wells of the chemotaxis chamber 50,000 PMN were then added and the bottom wells were filled with 25 Ml ofFMLP or ANP alone and in combination, or with 25 Ml of medium.…”