The insoluble antigenic fraction was superior in stimulating TNF-α, IL-10 and IL-4 production by CD4+ T cells, whereas the soluble antigenic fraction stimulated a higher production of IL-10 and IL-4 by T CD4+ cells and of TNF-α and IFN-γ by CD8+ T cells. In general, CD4+ T cells were the higher producers of inhibitory cytokines such as IL-10 and IL-4. Figure 1c shows representative

FACS dot plots. Many studies have been proposed to elucidate the mechanisms that account for the differences in susceptibility to Leishmania, but those are still unclear. Because of this reason, we directly determined the cellular sources and frequencies of cytokine-producing populations after stimulation with two different mitogens and the insoluble and soluble L. (V.) braziliensis antigens through flow see more cytometry. We observed, under stimulation with the selleck mitogens, that PMA plus ionomycin was able to induce a more powerful immune response than PHA, as seen by others (11,12). These polyclonal mitogens have been widely used in in vitro studies for cellular activation, but

as they stimulate different cellular pathways and because not all T cells undergo a likewise process, these may account for the differences observed in our study (5). Other possible explanation is the fact that the patients had an already Th2-predominant profile of cytokines because of their infection, which may impair a Th1-predominant profile. We can highlight that observation by looking at healthy controls that were higher producers of Th1 cytokines under PMA and ionomycin

stimulus and had a more mixed profile Th1 × Th2 under PHA. Focusing on a more specific stimulation, studies using different Leishmania antigens (1,4,5,9,13) demonstrated that these antigens were able to induce different levels of GBA3 cellular immune response and acknowledged that the search for antigenic molecules is relevant to the identification of new subunit candidates to vaccines and targets for immunotherapy. Therefore, it became important to characterize and assess the cellular immune response of patients with ACL stimulated with the soluble and insoluble antigens of L. (V.) braziliensis fractions to contribute to the searches. When analysing immunophenotypically the percentage of CD4+ and CD8+ T cells and the CD4/CD8 ratio, we observed an expansion of CD4+ T cells in a significant manner when compared with the control group, being similar results obtained by other authors studying leishmaniasis infection (8,9,14,15). On the other hand, the percentage of CD8+ T cells was slightly decreased compared to the control group. This could reflect the down-modulation of the immune status of the patients, as studies indicate the importance of CD8+ T cells in the healing process of the disease (3,8,9).