title: Interferon-gamma-inducing oral vaccination with Leishmania amazonensis antigens protects BALB/c and C57BL/6 mice against cutaneous leishmaniasis.
abstract: The induction of oral tolerance against disease-inducing antigens has emerged as a feasible strategy to prevent immunopathologies. In this study, we investigated the effect of oral immunization with whole antigens of Leishmania amazonensis promastigotes (LaAg) on murine cutaneous leishmaniasis. We found that two oral doses with 100 microg LaAg rendered BALB/c and C57BL/6 mice more resistant against subsequent infection with L. amazonensis. The oral vaccine also partially protected BALB/c mice against Leishmania major infection. Unlike the oral route, hepatic immunization was without effect, indicating a requirement for antigen passage through the gut mucosa. Oral LaAg significantly impaired the capacity of infected BALB/c mice to mount a disease-associated hypersensitivity response, compatible with peripheral tolerization. Both IFN-gamma and IL-10, but not IL-4 were greatly elevated in the mesenteric lymph nodes whereas only IFN-gamma was increased in the peripheral lymph nodes, compatible with a TH1 cytokine response. Gamma delta TCR+ T cells may be an important component in antigenic sensitization of the gut mucosa since their depletion during oral immunization reverted protection. These results demonstrate for the first time the feasibility of using the oral route of immunization to induce protection against cutaneous leishmaniasis using a crude parasite antigen.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21.949-900 Rio de Janeiro, Brazil.
authors.forename: Eduardo Fonseca
authors.initials: EF
authors.lastname: Pinto
authors.forename: Marcelle
authors.initials: M
authors.lastname: de Mello Cortezia
authors.forename: Bartira
authors.initials: B
authors.lastname: Rossi-Bergmann
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D004342:Drug Hypersensitivity / Q000276:immunology; D007267:Injections; D007279:Injections, Subcutaneous; D007369:Interferon Inducers / Q000494:pharmacology*; D007371:Interferon-gamma / Q000096:biosynthesis*; D007894:Leishmania mexicana / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D008099:Liver / Q000502:physiology; D008198:Lymph Nodes / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D012867:Skin / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology; D014611:Vaccination
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D007369:Interferon Inducers; D016052:Protozoan Vaccines; D016692:Receptors, Antigen, T-Cell, gamma-delta; D007371:Interferon-gamma