Interleukin-6 expression in human neutrophil and eosinophil peripheral blood granulocytes

Abstract

Human peripheral blood granulocytes were analyzed for expression of interleukin-6 (IL-6) using reverse-transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization. Neutrophil granulocytes from healthy donors were shown to express variable levels of IL-6. This expression was rapidly down-regulated after the removal of the cells from the circulating blood. In vitro culture of neutrophils abolished IL-6 expression, which could be reactivated by addition of GM-CSF to the culture medium. Constitutive expression of IL-6 was instead demonstrated in eosinophil granulocytes purified from normal donors and from a hypereosinophilic patient. In situ hybridization of unstimulated granulocytes confirmed that IL-6 expression occurs both in eosinophils and in neutrophils from peripheral blood. These findings show that granulocytes can actively contribute to cytokine expression in the peripheral blood and suggest their role in the afferent limb of the immune response, since by IL-6 production they might modulate T- and B- lymphocyte functions, granulocyte self-priming, and endothelial interaction.

Impaired innate immune response of leukocytes from ascitic fluid of patients with spontaneous bacterial peritonitis

“…2B). This finding can be explained by the IL-6 production of recently recruited neutrophils in PosC-SBP [19]. In recent studies, IL-6 was also shown to suppress neutrophil apoptosis via a platelet-activating factor-like mechanism [20,21].…”

Eosinophils Accelerate Pathogenesis of Psoriasis by Supporting an Inflammatory Milieu that Promotes Neutrophil Infiltration

“…Expression of Tnf and Ccl11 (encoding CC chemokine ligand 11, the cognate ligand for CCR3) did not significantly differ between IMQ-treated WT and DdblGATA mice ( Figure 4). Expression of Il6 and Il23 was lower in DdblGATA mice than in WT mice even without IMQ application ( Figure 4), suggesting that eosinophils are a cellular source of those inflammatory mediators (Guerra et al, 2017;Melani et al, 1993).…”

Eosinophils: multifaceted biological properties and roles in health and disease

“…Furthermore, when stimulated with eotaxin (CCL11) or RANTES (CCL5), human eosinophils rapidly release stored IL-4 by vesicular transport to the local milieu (46). Several other cytokines and chemokines are also transcribed and ⁄ or produced by eosinophils (3,31); for example, by reverse transcriptase polymerase chain reaction, constitutive expression of IL-6 and IL-10 mRNA was detected in blood eosinophils (44,45,47,48). Eosinophils also express a proinflammatory cytokine, TNF-a, and chemokines, such as MIP-1a (CCL3) and RANTES (CCL5) (49,50).…”