Interleukin-15 increases Paracoccidioides brasiliensis killing by human neutrophils.
Interleukin-15 is a cytokine produced by a wide range of different cell types, including macrophages, in response to lipopolysaccharide or microbial infection. This cytokine may play a crucial role in the activation of phagocytic cells against pathogens, especially during innate immune response. The effects of IL-15 on human polymorphonuclear leukocyte fungicidal activity against a highly virulent Paracoccidioides brasiliensis strain were investigated. Pretreatment of human neutrophils from healthy individuals with IL-15 for 18 hours increased cell fungicidal activity in a dose-dependent manner. In addition, the exposure to IL-15 induced an increase in neutrophil oxidative burst as evaluated by superoxide anion and H(2)O(2) release. Catalase inhibited fungicidal activity supporting a role for H(2)O(2) in fungus killing. In contrast, IL-8 and TNF-alpha levels were not affected by IL-15 suggesting that its effects were not mediated by these cytokines. Together, these results show that IL-15 is a potent stimulant of antifungal activities in human neutrophils, at least in part by a mechanism dependent on oxidative metabolism.
Tavian
Elisandra Garcia
EG
Department of Microbiology and Immunology, Biosciences Institute, São Paulo State University (UNESP), Botucatu, CEP 18618-000, S.P., Brazil.
Dias-Melicio
Luciane Alarcão
LA
Acorci
Michele Janegitz
MJ
Graciani
Ana Paula Bordon
AP
Peraçoli
Maria Terezinha Serrão
MT
Soares
Angela Maria Victoriano de Campos
AM
D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000276:immunology; D019409:Interleukin-15 / Q000276:immunology / Q000494:pharmacology*; D016209:Interleukin-8 / Q000276:immunology; D009504:Neutrophils / Q000276:immunology* / Q000382:microbiology; D010084:Oxidation-Reduction / Q000187:drug effects; D010228:Paracoccidioides / Q000276:immunology*; D010229:Paracoccidioidomycosis / Q000276:immunology*; D010587:Phagocytosis / Q000187:drug effects* / Q000276:immunology; D013481:Superoxides / Q000276:immunology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
C508606:CXCL8 protein, human; D019409:Interleukin-15; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D006861:Hydrogen Peroxide