Granule release, polymorphonuclear neutrophils

The increased expression of adhesion molecules by the endothelium may activate polymorphonuclear neutrophils (PMN) in rabbits [72], During endotoxic shock, activated PMNs release their granule content and secrete both proinflammatory and cytotoxic molecules. Pickaver et al. [73] were the first to show PMN cytotoxicity against tumor cells. We showed that PMNs are toxic for PROb colon tumor cells [74] in BDEX rats. In vivo, PMNs have been implicated in the Schwartzman reaction [75], and may be involved in LPS-induced tumor necrosis. PMNs, when activated by LPS, synthesize and release NO. The role of NO in tumor growth will be discussed later. The decrease in tumor growth after intradermal injections of LPS is attributed to the induction of TNF-a secretion by PMNs both in intradermal tumors (Meth A sarcoma in BALB/c mice, MH-134 hepatoma in C3H/He mice, Lewis Lung carcinomas in C57BL/6 mice) and pulmonary Meth A metastases [76,77],... 

IL-17 induces the production of IL-8 in endothelial and parenchymal cells, indicating an indirect role in PMN recruitment. IL-8 is a potent chemoattractant for polymorphonuclear neutrophils (PMN) and can also stimulate the release of neutrophil granules and the respiratory burst of these cells [5,71-78]. In their study, Kostulas et al. found that the proinflammatory cytokine IL-17 was elevated systemically after ischemic stroke. IL-17 induces the secretion of cytokines, including IL-8, and enhances the expression of ICAM-1 in cultures of stromal cells and human fibroblasts [5,77,79]. 

Human leukocyte elastase (HLE EC 3.4.21.37 also known as human neutrophil elastase, HNE) [1] is a strongly basic glycoprotein which is produced by polymorphonuclear leukocytes (neutrophils) and is released from their azurophilic granules [2]. HLE exists as at least four distinct isozymes, which range in molecular weight from 24 [3] to 30 kDa [4] and appear to differ only in carbohydrate content [5]. Furthermore, human sputum elastase (HSE), which is isolated from purulent sputum as at least five distinct isozymes [6], is both immunologically and catalytically indistinguishable from HLE [7] and is believed to be identical to it. 

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