Blockade of CTLA-4 promotes the development of effector CD8(+) T lymphocytes and the therapeutic effect of vaccination with an attenuated protozoan expressing NY-ESO-1. por Dos Santos, L, Galvão-Filho, B, de Faria, P, Junqueira, C, Dutra, MS, Teixeira, S, Rodrigues, M, Ritter, G, Bannard, O, Fearon, D, Antonelli, L, Gazzinelli, RT