title: Human anti-saliva immune response following experimental exposure to the visceral leishmaniasis vector, Lutzomyia longipalpis.
abstract: Experiments in animals verified that phlebotomine saliva enhances Leishmania infection, and vaccination with saliva prevents disease. We have shown that individuals from an endemic area of visceral leishmaniasis displayed robust antibody responses to saliva from the vector Lutzomyia longipalpis, which correlated with anti-parasite cell-mediated immunity. Here, we explored human anti-saliva responses following exposure to sand flies, using an in vivo bite model in which normal volunteers were exposed four times to 30 laboratory-reared Lu. longipalpis. Following the third exposure, normal volunteers developed diverse dermatological reactions at the site of insect bite. Serum from normal volunteers displayed high levels of anti-salivary gland sonicate IgG1, IgG4 and IgE as well as several salivary gland proteins. Furthermore, following in vitro stimulation with salivary gland sonicate, there was an increased frequency of CD4(+)CD25(+) and CD8(+)CD25(+) T cells as well as IFN-gamma and IL-10 synthesis. Strikingly, 1 year after the first exposure, PBMC from the volunteers displayed recall IFN-gamma responses that correlated with a significant reduction in infection rates using a macrophage-lymphocyte autologous culture. Together, these data suggest that human immunization against sand fly saliva is feasible and recall responses are obtained even 1 year after exposure, opening perspectives for vaccination in man.
authors.affiliation: Centro de Pesquisas Gonçalo Moniz (FIOCRUZ) and Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Vera
authors.initials: V
authors.lastname: Vinhas
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Andrade
authors.forename: Fábio
authors.initials: F
authors.lastname: Paes
authors.forename: Andréa
authors.initials: A
authors.lastname: Bomura
authors.forename: Jorge
authors.initials: J
authors.lastname: Clarencio
authors.forename: José C
authors.initials: JC
authors.lastname: Miranda
authors.forename: André
authors.initials: A
authors.lastname: Báfica
authors.forename: Aldina
authors.initials: A
authors.lastname: Barral
authors.forename: Manoel
authors.initials: M
authors.lastname: Barral-Netto
mesh_terms: D000328:Adult; D000818:Animals; D015153:Blotting, Western; D016207:Cytokines / Q000097:blood / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D019476:Insect Proteins / Q000276:immunology*; D007303:Insect Vectors / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000517:prevention & control* / Q000635:transmission; D008297:Male; D011576:Psychodidae / Q000276:immunology*; D012463:Saliva / Q000276:immunology*; D012471:Salivary Proteins and Peptides / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D016207:Cytokines; D007074:Immunoglobulin G; D019476:Insect Proteins; D012471:Salivary Proteins and Peptides; D007073:Immunoglobulin E