title: Evaluation of immune responses and protection induced by A2 and nucleoside hydrolase (NH) DNA vaccines against Leishmania chagasi and Leishmania amazonensis experimental infections.
abstract: Several antigens have been tested as vaccine candidates against Leishmania infections but controversial results have been reported when different antigens are co-administered in combined vaccination protocols. Immunization with A2 or nucleoside hydrolase (NH) antigens was previously shown to induce Th1 immune responses and protection in BALB/c mice against Leishmania donovani and L. amazonensis (A2) or L. donovani and L. mexicana (NH) infections. In this work, we investigated the protective efficacy of A2 and NH DNA vaccines, in BALB/c mice, against L. amazonensis or L. chagasi challenge infection. Immunization with either A2 (A2-pCDNA3) or NH (NH-VR1012) DNA induced an elevated IFN-gamma production before infection; however, only A2 DNA immunized mice were protected against both Leishmania species and displayed a sustained IFN-gamma production and very low IL-4 and IL-10 levels, after challenge. Mice immunized with NH/A2 DNA produced higher levels of IFN-gamma in response to both specific recombinant proteins (rNH or rA2), but displayed higher IL-4 and IL-10 levels and increased edema and parasite loads after L. amazonensis infection, as compared to A2 DNA immunized animals. These data extend the characterization of the immune responses induced by NH and A2 antigens as potential candidates to compose a defined vaccine and indicate that a highly polarized type 1 immune response is required for improvement of protective levels of combined vaccines against both L. amazonensis and L. chagasi infections.
authors.affiliation: Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Francisca H C
authors.initials: FH
authors.lastname: Zanin
authors.forename: Eduardo A F
authors.initials: EA
authors.lastname: Coelho
authors.forename: Carlos A P
authors.initials: CA
authors.lastname: Tavares
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Marques-da-Silva
authors.forename: Miriam Maria
authors.initials: MM
authors.lastname: Silva Costa
authors.forename: Simone A
authors.initials: SA
authors.lastname: Rezende
authors.forename: Ricardo T
authors.initials: RT
authors.lastname: Gazzinelli
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Fernandes
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D016054:DNA, Protozoan / Q000235:genetics / Q000276:immunology*; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D015847:Interleukin-4 / Q000096:biosynthesis / Q000276:immunology; D007891:Leishmania / Q000235:genetics / Q000276:immunology*; D007896:Leishmaniasis / Q000276:immunology* / Q000517:prevention & control; D054332:Leishmaniasis Vaccines / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D009699:N-Glycosyl Hydrolases / Q000235:genetics* / Q000276:immunology; D015800:Protozoan Proteins / Q000235:genetics* / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology
chemical_list: C107645:A2 protein, Leishmania donovani; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D054332:Leishmaniasis Vaccines; D015800:Protozoan Proteins; D019444:Vaccines, DNA; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma; D009699:N-Glycosyl Hydrolases