title: Repeated exposure to Lutzomyia intermedia sand fly saliva induces local expression of interferon-inducible genes both at the site of injection in mice and in human blood.
abstract: During a blood meal, Lutzomyia intermedia sand flies transmit Leishmania braziliensis, a parasite causing tegumentary leishmaniasis. In experimental leishmaniasis, pre-exposure to saliva of most blood-feeding sand flies results in parasite establishment in absence of any skin damages in mice challenged with dermotropic Leishmania species together with saliva. In contrast, pre-immunization with Lu. intermedia salivary gland sonicate (SGS) results in enhanced skin inflammatory exacerbation upon co-inoculation of Lu. intermedia SGS and L. braziliensis. These data highlight potential unique features of both L. braziliensis and Lu. intermedia. In this study, we investigated the genes modulated by Lu. intermedia SGS immunization to understand their potential impact on the subsequent cutaneous immune response following inoculation of both SGS and L. braziliensis. The cellular recruitment and global gene expression profile was analyzed in mice repeatedly inoculated or not with Lu. intermedia. Microarray gene analysis revealed the upregulation of a distinct set of IFN-inducible genes, an immune signature not seen to the same extent in control animals. Of note this INF-inducible gene set was not induced in SGS pre-immunized mice subsequently co-inoculated with SGS and L. braziliensis. These data suggest the parasite prevented the upregulation of this Lu. intermedia saliva-related immune signature. The presence of these IFN-inducible genes was further analyzed in peripheral blood mononuclear cells (PBMCs) sampled from uninfected human individuals living in a L. braziliensis-endemic region of Brazil thus regularly exposed to Lu. intermedia bites. PBMCs were cultured in presence or absence of Lu. intermedia SGS. Using qRT-PCR we established that the IFN-inducible genes induced in the skin of SGS pre-immunized mice, were also upregulated by SGS in PBMCs from human individuals regularly exposed to Lu. intermedia bites, but not in PBMCs of control subjects. These data demonstrate that repeated exposure to Lu. intermedia SGS induces the expression of potentially host-protective IFN-inducible genes.
authors.affiliation: Department of Biochemistry, and WHO-Immunology Research and Training Center, University of Lausanne, Epalinges, Switzerland.
authors.forename: Tiffany
authors.initials: T
authors.lastname: Weinkopff
authors.affiliation: Centro de Pesquisas Goncalo Moniz, Fundacao Oswaldo Cruz, (FIOCRUZ), Salvador, Brazil ; Instituto Nacional de Ciência e Tecnologia de Investigação em Imunologia (iii-INCT), Salvador, Brazil.
authors.forename: Camila I
authors.initials: CI
authors.lastname: de Oliveira
authors.affiliation: Centro de Pesquisas Goncalo Moniz, Fundacao Oswaldo Cruz, (FIOCRUZ), Salvador, Brazil ; National Institute of Science and Technology in Tropical Diseases (CNPq), Salvador, Brazil.
authors.forename: Augusto M
authors.initials: AM
authors.lastname: de Carvalho
authors.affiliation: Department of Biochemistry, and WHO-Immunology Research and Training Center, University of Lausanne, Epalinges, Switzerland.
authors.forename: Yazmin
authors.initials: Y
authors.lastname: Hauyon-La Torre
authors.affiliation: Servico de Imunologia, Complexo Hospitalar Universitario Prof. Edgar Santos, Universidade Federal da Bahia, Salvador, Brazil.
authors.forename: Aline C
authors.initials: AC
authors.lastname: Muniz
authors.affiliation: Centro de Pesquisas Goncalo Moniz, Fundacao Oswaldo Cruz, (FIOCRUZ), Salvador, Brazil.
authors.forename: Jose Carlos
authors.initials: JC
authors.lastname: Miranda
authors.affiliation: Centro de Pesquisas Goncalo Moniz, Fundacao Oswaldo Cruz, (FIOCRUZ), Salvador, Brazil ; Instituto Nacional de Ciência e Tecnologia de Investigação em Imunologia (iii-INCT), Salvador, Brazil.
authors.forename: Aldina
authors.initials: A
authors.lastname: Barral
authors.affiliation: Department of Biochemistry, and WHO-Immunology Research and Training Center, University of Lausanne, Epalinges, Switzerland.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Tacchini-Cottier
mesh_terms: D000818:Animals; D001938:Brazil; D002478:Cells, Cultured; D005260:Female; D020869:Gene Expression Profiling; D006790:Host-Parasite Interactions; D006801:Humans; D007372:Interferons / Q000276:immunology; D007892:Leishmania braziliensis / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011576:Psychodidae / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D012463:Saliva / Q000276:immunology*
chemical_list: D007372:Interferons