CD8+ T cells are not required for vaccine-induced immunity against Leishmania amazonensis in IL-12/23P40(-/-) C57BL/6 mice.
Vaccine-induced protection against leishmaniasis is largely dependent on cell-mediated type 1 response and IL-12-driven IFN-gamma production. Surprisingly, our previous data showed that IL-12/23p40(-/-) mice could be vaccinated against L. amazonensis and were able to produce limited amounts of IFN-gamma. Since the role of CD8+ T in immunization against L. amazonensis is obscure, the aim of this study was to evaluate the effects of CD8+ cells in protection against L. amazonensis in IL-12/23p40(-/-) mice. In order to deplete CD8+ cells, one group of vaccinated animals was treated with anti-CD8 mAb. Infection was followed for 8 weeks. The vaccinated CD8+ -depleted group developed smaller lesions than the non-depleted group. CD8 depletion did not affect tissue parasitism or antibody response against the parasite, and treated animals displayed milder inflammation and better tissue integrity. IFN-gamma production in spleen and draining lymph node was impaired in the depleted group, suggesting that CD8+ cells produced this cytokine in IL-12-independent vaccination. Such results suggest that this T cell subset contributes to augmented pathology in IL12/23p40(-/-) mice vaccinated and challenged with L. amazonensis. Although these cells could produce some IFN-gamma the in the absence of IL-12, they do not affect the parasite tissue load.
Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas/ICB, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
Mayra Xiomara
MX
Hernández Sanabria
Luís Carlos Crocco
LC
Afonso
Denise
D
Golgher
Wagner Luiz
WL
Tafuri
Leda Quercia
LQ
Vieira
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis / Q000172:deficiency / Q000276:immunology; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D053762:Interleukin-12 Subunit p40 / Q000172:deficiency* / Q000276:immunology; D007891:Leishmania / Q000276:immunology*; D007896:Leishmaniasis / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D054332:Leishmaniasis Vaccines / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D023421:Models, Animal
D000913:Antibodies, Protozoan; D016207:Cytokines; D053762:Interleukin-12 Subunit p40; D054332:Leishmaniasis Vaccines; D007371:Interferon-gamma