The Journal of immunology : official journal of the American Association of Immunologists
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Thymic stromal lymphopoietin (TSLP) is elevated in asthma and triggers dendritic cell-mediated activation of Th2 inflammatory responses. Although TSLP has been shown to be produced mainly by airway epithelial cells, the regulation of epithelial TSLP expression has not been extensively studied. We investigated the expression of TSLP in cytokine- or TLR ligand-treated normal human bronchial epithelial cells (NHBE). ⋯ The potent topical glucocorticoid fluticasone propionate significantly suppressed dsRNA-dependent TSLP production in NHBE. These results suggest that the expression of TSLP is induced in airway epithelial cells by stimulation with the TLR3 ligand and Th2 cytokines and that this response is suppressed by glucocorticoid treatment. This implies that respiratory viral infection and the recruitment of Th2 cytokine producing cells may amplify Th2 inflammation via the induction of TSLP in the asthmatic airway.
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CD4(+) T cells produce IFN-gamma contributing to corneal perforation in C57BL/6 (B6) mice after Pseudomonas aeruginosa infection. To determine the role of NK and NKT cells, infected corneas of B6 mice were dual immunolabeled. Initially, more NKT than NK cells were detected, but as disease progressed, NK cells increased, while NKT cells decreased. ⋯ In vitro studies tested whether endotoxin (LPS) stimulated Langerhans cells and macrophages (Mphi; from B6 mice) provided signals to activate NKT cells. LPS up-regulated mRNA expression for IL-12p40, costimulatory molecules CD80 and CD86, NF-kappaB, and CD1d, and addition of rIFN-gamma potentiated Mphi CD1d levels. Together, these data suggest that Langerhans cell/Mphi recognition of microbial LPS regulates IL-12p40 (and CD1d) driven IFN-gamma production by NKT cells, that IFN-gamma is required to optimally activate NK cells to produce IFN-gamma, and that depletion of both NKT/NK cells results in earlier corneal perforation.
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Comparative Study
Chronic sepsis mortality characterized by an individualized inflammatory response.
Late mortality in septic patients often exceeds the lethality occurring in acute sepsis, yet the immunoinflammatory alterations preceding chronic sepsis mortality are not well defined. We studied plasma cytokine concentrations preceding late septic deaths (days 6-28) in a murine model of sepsis induced by polymicrobial peritonitis. The late prelethal inflammatory response varied from a virtually nonexistent response in three of 14 to a mixed response in eight of 14 mice to the concurrent presence of nearly all measured cytokines, both proinflammatory and anti-inflammatory in three of 14 mice. ⋯ For high mobility group box 1, late mortality was signaled by its decrease in plasma levels (591 vs 864 ng/ml). These results demonstrate that impeding mortality in the chronic phase of sepsis may be accurately predicted by plasma biomarkers, providing a mechanistic basis for individualized therapy. The pattern of late prelethal responses suggest that the systemic inflammatory response syndrome to compensatory anti-inflammatory response syndrome transition paradigm fails to follow a simple linear pattern.