Modulation of γδ T-cell activation by neutrophil elastase

γδ T cells are non-conventional, innate-like T cells, characterized by a restricted T-cell receptor repertoire. They participate in protective immunity responses against extracellular and intracellular pathogens, tumour surveillance, modulation of innate and adaptive immune responses, tissue healing, epithelial cell maintenance and regulation of physiological organ function. In this study, we investigated the role of neutrophils during the activation of human blood γδ T cells through CD3 molecules. We found that the up-regulation of CD69 expression, and the production of interferon-γ and tumour necrosis factor-α induced by anti-CD3 antibodies was potentiated by neutrophils. We found that inhibition of caspase-1 and neutralization of interleukin-18 did not affect neutrophil-mediated modulation. By contrast, the treatment with serine protease inhibitors prevented the potentiation of γδ T-cell activation induced by neutrophils. Moreover, the addition of elastase to γδ T-cell culture increased their stimulation, and the treatment of neutrophils with elastase inhibitor prevented the effect of neutrophils on γδ T-cell activation. Furthermore, we demonstrated that the effect of elastase on γδ T cells was mediated through the protease-activated receptor, PAR1, because the inhibition of this receptor with a specific antagonist, RWJ56110, abrogated the effect of neutrophils on γδ T-cell activation.Fil: Towstyka, Nadia Yasmín. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Shiromizu, Carolina Maiumi. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Keitelman, Irene Angélica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Sabbione, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Salamone, Gabriela Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Cátedra de Microbiología, Parasitología e Inmunología; ArgentinaFil: Geffner, Jorge Raúl. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Cátedra de Microbiología, Parasitología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Trevani, Analía Silvina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Cátedra de Microbiología, Parasitología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Jancic, Carolina Cristina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Cátedra de Microbiología, Parasitología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Efficient Capture of Infected Neutrophils by Dendritic Cells in the Skin Inhibits the Early Anti-Leishmania Response

Neutrophils and dendritic cells (DCs) converge at localized sites of acute inflammation in the skin following pathogen deposition by the bites of arthropod vectors or by needle injection. Prior studies in mice have shown that neutrophils are the predominant recruited and infected cells during the earliest stage of Leishmania major infection in the skin, and that neutrophil depletion promotes host resistance to sand fly transmitted infection. How the massive influx of neutrophils aimed at wound repair and sterilization might modulate the function of DCs in the skin has not been previously addressed. The infected neutrophils recovered from the skin expressed elevated apoptotic markers compared to uninfected neutrophils, and were preferentially captured by dermal DCs when injected back into the mouse ear dermis. Following challenge with L. major directly, the majority of the infected DCs recovered from the skin at 24 hr stained positive for neutrophil markers, indicating that they acquired their parasites via uptake of infected neutrophils. When infected, dermal DCs were recovered from neutrophil depleted mice, their expression of activation markers was markedly enhanced, as was their capacity to present Leishmania antigens ex vivo. Neutrophil depletion also enhanced the priming of L. major specific CD4+ T cells in vivo. The findings suggest that following their rapid uptake by neutrophils in the skin, L. major exploits the immunosuppressive effects associated with the apoptotic cell clearance function of DCs to inhibit the development of acquired resistance until the acute neutrophilic response is resolved

IFN-gamma-Stimulated Neutrophils Suppress Lymphocyte Proliferation through Expression of PD-L1

Contains fulltext : 119302.pdf (publisher's version ) (Open Access)During systemic inflammation different neutrophil subsets are mobilized to the peripheral blood. These neutrophil subsets can be distinguished from normal circulating neutrophils (CD16(bright)/CD62L(bright)), based on either an immature CD16(dim)/CD62L(bright) or a CD16(bright)/CD62L(dim) phenotype. Interestingly, the latter neutrophil subset is known to suppress lymphocyte proliferation ex vivo, but how neutrophils become suppressive is unknown. We performed transcriptome analysis on the different neutrophil subsets to identify changes in mRNA expression that are relevant for their functions. Neutrophil subsets were isolated by fluorescence-activated cell sorting from blood of healthy volunteers that were administered a single dose of lipopolysaccharide (2 ng/kg i.v.) and the transcriptome was determined by microarray analysis. Interestingly, the CD16(bright)/CD62L(dim) suppressive neutrophils showed an interferon-induced transcriptome profile. More importantly, IFN-gamma, but not IFN-alpha or IFN-beta stimulated neutrophils, acquired the capacity to suppress lymphocyte proliferation through the expression of programmed death ligand 1 (PD-L1). These data demonstrate that IFN-gamma-induced expression of PD-L1 on neutrophils enables suppression of lymphocyte proliferation. Specific stimulation of neutrophils present at the inflammatory sites might therefore have a pivotal role in regulating lymphocyte-mediated inflammation and autoimmune disease