title: Analysis of the protective potential of antigens released by Leishmania (Viannia) shawi promastigotes.
abstract: Leishmania (Viannia) shawi causes cutaneous lesions in humans. Parasite antigens conferring significant protection against American tegumentar leishmaniosis (ATL) might be important for the development of effective vaccine. Therefore, this work evaluates the protective effect of antigenic fractions released by L. shawi. Antigens released by promastigotes to culture medium were concentrated and isolated by SDS-PAGE. The three main fractions LsPass1 (>75 kDa), LsPass2 (75-50 kDa) and LsPass3 (<50 kDa) were electro-eluted according with their molecular mass. Immunized BALB/c mice were challenged with L. shawi promastigotes and the course of infection monitored during 5 weeks. LsPass1-challenged mice showed no protection, however, a strong degree of protection associated to smaller lesions and high expression of IFN-γ and TNF-α by CD4(+) T, CD8(+) T and double negative CD4CD8 cells was achieved in LsPass3-challenged mice. Furthermore, LsPass2-challenged mice showed an intermediated degree of protection associated to high levels of IFN-γ, IL-4 and IL-10 mRNA. In spite of increased expression of IFN-γ and TNF-α, high amounts of IL-4 and IL-10 mRNA were also detected in LsPass3-challenged mice indicating a possible contribution of these cytokines for the persistence of a residual number of parasites that may be important in inducing long-lasting immunity. Therefore, LsPass3 seems to be an interesting alternative that should be considered in the development of an effective vaccine against ATL.
authors: Laboratório de Patologia de Moléstias Infecciosas, Faculdade de Medicina, Universidade de São Paulo, Brazil.
authors: Luiz Felipe Domingues
authors: LF
authors: Passero
authors: Cláudia
authors: C
authors: Marques
authors: Inês
authors: I
authors: Vale-Gato
authors: Carlos Eduardo Pereira
authors: CE
authors: Corbett
authors: Márcia Dalastra
authors: MD
authors: Laurenti
authors: Gabriela
authors: G
authors: Santos-Gomes
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage* / Q000737:chemistry / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D007114:Immunization; D007156:Immunologic Memory; D007891:Leishmania / Q000276:immunology*; D054332:Leishmaniasis Vaccines / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology / Q000517:prevention & control*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D058408:Th1-Th2 Balance
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D054332:Leishmaniasis Vaccines