title: Interferon-gamma production by human neutrophils upon stimulation by IL-12, IL-15 and IL-18 and challenge with Paracoccidioides brasiliensis.
abstract: Paracoccidiodomycosis is a systemic mycosis caused by the fungus Paracoccidioides brasiliensis (Pb), which is endemic in Latin America. The host innate immune response against the fungus has been well characterized and several studies have shown the important role played by phagocytic cells. Our laboratory has studied the relationship between human neutrophils (PMNs)/Pb, focusing the effector mechanisms of these cells against the fungus. However, in last years, studies have shown that in addition to their phagocytic and killer functions, PMNs can modulate and instruct the immune response, since these cells have been shown to produce and release several cytokines. Thus, we evaluated whether PMNs stimulated with Pb can modulate the immune response to a Th1 phenotype through the production of IFN-γ, as well as the role of "pattern-recognition receptors" (PRRs) such as TLR2, TLR4 and Dectin-1 in this production. Furthermore, we asked whether activation of the cells with the cytokines IL-12, IL-15 and IL-18 could result in increased levels of this cytokine. Peripheral blood PMNs obtained from 20 healthy donors were nonactivated or activated with IL-12, IL-15 or IL-18 in different concentrations and challenged with strain 18 Pb (Pb18) for 2 h, 4 h, 12 h, 24 h and 48 h and evaluated for IFN-γ production, by ELISA. In other experiments, PMNs were treated with monoclonal antibodies anti-TLR2, TLR4 and Dectin-1, challenged with Pb and evaluated for IFN-γ production. We found that Pb induces human PMNs to produce IFN-γ, probably by binding to TLR4 and Dectin-1 receptors expressed by these cells. Moreover, IFN-γ levels were significantly increased when cells were activated with each of the tested cytokines or a combination of two of them, being the association IL-12 plus IL-15 the most effective. The results support our hypothesis that during infection by Pb, human PMNs modulate the adaptive immune response to a Th1 response pattern, via IFN-γ production.
authors.affiliation: Department of Tropical Diseases, Botucatu School of Medicine, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil; Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil. Electronic address: rodriguesdn@yahoo.com.br.
authors.forename: Daniela Ramos
authors.initials: DR
authors.lastname: Rodrigues
authors.affiliation: Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil; Department of Pathology, Botucatu Medical School, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil.
authors.forename: Reginaldo Keller
authors.initials: RK
authors.lastname: Fernandes
authors.affiliation: Department of Tropical Diseases, Botucatu School of Medicine, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil; Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil.
authors.forename: Helanderson de Almeida
authors.initials: Hde A
authors.lastname: Balderramas
authors.affiliation: Flow Cytometry Laboratory, Amaral Carvalho Foundation, Rua: Dona Silvéria, 150, Jaú, SP 17210-080, Brazil.
authors.forename: Marcimara
authors.initials: M
authors.lastname: Penitenti
authors.affiliation: Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil; Department of Pathology, Botucatu Medical School, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil.
authors.forename: Tatiana Fernanda
authors.initials: TF
authors.lastname: Bachiega
authors.affiliation: Department of Tropical Diseases, Botucatu School of Medicine, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil.
authors.forename: Sueli Aparecida
authors.initials: SA
authors.lastname: Calvi
authors.affiliation: Department of Pathology, Botucatu Medical School, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil.
authors.forename: Luciane Alarcão
authors.initials: LA
authors.lastname: Dias-Melicio
authors.affiliation: Flow Cytometry Laboratory, Amaral Carvalho Foundation, Rua: Dona Silvéria, 150, Jaú, SP 17210-080, Brazil.
authors.forename: Maura Rosane Valério
authors.initials: MR
authors.lastname: Ikoma
authors.affiliation: Department of Tropical Diseases, Botucatu School of Medicine, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil; Department of Microbiology and Immunology, Institute of Biosciences, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior S/N, Botucatu, SP 18618-970, Brazil. Electronic address: acsoares@ibb.unesp.br.
authors.forename: Ângela Maria Victoriano de Campos
authors.initials: ÂM
authors.lastname: Soares
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000276:immunology; D018664:Interleukin-12 / Q000494:pharmacology*; D019409:Interleukin-15 / Q000494:pharmacology*; D020382:Interleukin-18 / Q000494:pharmacology; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000276:immunology; D018375:Neutrophil Activation / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D010228:Paracoccidioides / Q000276:immunology*; D010229:Paracoccidioidomycosis / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis / Q000276:immunology; D000099181:Dectin-1
chemical_list: D000911:Antibodies, Monoclonal; D007371:Interferon-gamma; D018664:Interleukin-12; D019409:Interleukin-15; D020382:Interleukin-18; D037181:Lectins, C-Type; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C546929:CLEC7A protein, human; D000099181:Dectin-1; C569274:IL15 protein, human; C495342:TLR2 protein, human; C495345:TLR4 protein, human
keywords: Human neutrophils; IFN-γ; PRRs; Paracoccidioides brasiliensis; Th1 response