title: Immunization with Leishmania infantum released proteins confers partial protection against parasite infection with a predominant Th1 specific immune response.
abstract: In this study, protective effect and immune response elicited by protein fractions LiRic1 (>75 kDa) and LiRic2 (<37 kDa) released by Leishmania infantum promastigotes were analysed in challenged BALB/c mice. Viable parasites were quantified in spleen and isolated CD4(+) and CD8(+) T cells were stimulated for evaluation of proliferative response and cytokine production. Immunization triggered 50.4-66.9% of parasite reduction. Stimulated CD4(+) T cells from challenged animals revealed high proliferation. IL-12 and IFN-gamma were released by CD4(+) T cells whereas IL-4 and IL-10 were impaired. LiRic1 and LiRic2 immunization gave partial protection and a CD4(+) Th1 response. LiRic2 generated IL-12 by CD8(+) T cells pointing to its participation in protective response. These results encourage further research on the development of a vaccine that provides long-lasting protection against zoonotic visceral leishmaniasis.
authors.affiliation: Unidade de Leishmanioses and Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa, Rua da Junqueira 96, 1349-008 Lisboa, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rosa
authors.forename: Cláudia
authors.initials: C
authors.lastname: Marques
authors.forename: Olivia Roos
authors.initials: OR
authors.lastname: Rodrigues
authors.forename: Gabriela M
authors.initials: GM
authors.lastname: Santos-Gomes
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D007114:Immunization; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D018314:Leishmania infantum / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000276:immunology / Q000517:prevention & control*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D015800:Protozoan Proteins / Q000276:immunology*; D013154:Spleen / Q000469:parasitology; D018417:Th1 Cells / Q000276:immunology*
chemical_list: D015800:Protozoan Proteins; D018664:Interleukin-12; D007371:Interferon-gamma