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Emigration, cytokines

In the very early phases of the acute inflammatory response most of the cells invading the damaged area are polymorphonuclear neutrophils, also denoted as PMNs, which serve as initial line of defense and source of proinflammatory cytokines. These cells, which usually live for 4-5 days, circulate in the blood until they are attracted by chemokines into injured tissues. Whereas physical injury does not recruit many neutrophils, infections with bacteria or fungi elicit a striking neutrophil response. The characteristic pus of a bacterial abscess is composed mainly of apoptotic (apoptosis) and necrotic PMNs. Emigration of neutrophils from the blood starts with a process denoted as margination where neutrophils come to lie at the periphery of flowing blood cells and adhere to endothelial cells (Fig. 1). L-Selectin is expressed... [Pg.628]

Inflammation. Figure 1 Sequence of events in the recruitment of leukocytes in postcapillary venules adjacent to injured tissue. At the site of lesion, diverse reactive substances stimulate the endothelium to produce inflammatory cytokines, chemoattractants and other inflammatory mediators. The cytokine-activated endothelium expresses adhesion molecules that lead to the low affinity interactions between leukocytes and endothelium, which is mediated by selectins and described as rolling. Subsequently integrins mediate the firm adhesion of leukocytes, which allows emigration of the cells from venules into the interstitial compartment. Activated mast cells, PMNs and macrophages secrete cytokines (TNFa), lipid mediators (LTB4) and other inflammatory players (histamine, NO). [Pg.628]

Chemokines A large family of cytokines having a wide variety of biological actions that are generally associated with inducing mobilization and activation of immune cells a contraction of chemotactic cytokines. See Atkins, PC. and Wasserman, S.I., Chemotactic mediators, Clin. Rev. Allergy 1, 385-395, 1983 Hayashi, H., Honda, M., Shimokawa, Y., and Hirashima, M., Chemotactic factors associated with leukocyte emigration in immune tissue injury their separation, characterization, and functional specificity. [Pg.70]


See other pages where Emigration, cytokines is mentioned: [Pg.138]    [Pg.138]    [Pg.1788]    [Pg.230]    [Pg.18]    [Pg.53]    [Pg.153]    [Pg.40]    [Pg.28]    [Pg.4]    [Pg.505]    [Pg.21]    [Pg.458]   


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Emigration

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