Interleukin-15 increases Paracoccidioides brasiliensis killing by human neutrophils

• Published in: Cytokine (Philadelphia, Pa.) Vol. 41; no. 1; pp. 48 - 53
• Main Authors: Tavian, Elisandra Garcia, Dias-Melicio, Luciane Alarcão, Acorci, Michele Janegitz, Graciani, Ana Paula Bordon, Peraçoli, Maria Terezinha Serrão, Soares, Angela Maria Victoriano de Campos
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 2008
• Subjects: Cells, Cultured; Dose-Response Relationship, Drug; Fungicidal activity; Human neutrophil; Humans; Hydrogen peroxide; Hydrogen Peroxide - immunology; IL-15; Interleukin-15 - immunology; Interleukin-15 - pharmacology; Interleukin-8 - immunology; Neutrophils - immunology; Neutrophils - microbiology; Oxidation-Reduction - drug effects; Paracoccidioides - immunology; Paracoccidioides brasiliensis; Paracoccidioidomycosis - immunology; Phagocytosis - drug effects; Phagocytosis - immunology; Superoxides - immunology; Time Factors; Tumor Necrosis Factor-alpha - immunology; Human neutrophil; IL-15; Hydrogen peroxide; Fungicidal activity; Paracoccidioides brasiliensis
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/j.cyto.2007.10.011

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
2O
2 release. Catalase inhibited fungicidal activity supporting a role for H
2O
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.