Figure 6.

Inhibition of host leishmanicidal responses after infection of 9-O-AcSA^high promastigotes within macrophages as compared to their de-O-acetylated forms. (a) Reduced levels of NO production subsequent to infection with 9-O-AcSA^high promastigotes. Macrophages were incubated with promastigotes before (black square) and after de-O-acetylation (lined square) and liberated NO were estimated as described in [68]. Naïve macrophages served as controls (white square). (b)-(c) Decreased production of IL-12 and IFN-γ after infection with 9-O-AcSA^high promastigotes. Macrophages were infected with promastigotes before (black square) and after de-O-acetylation (lined square) and cytokines were detected in the supernatants by ELISA as described in detail in [68]. Macrophages without infection served as controls (white square; reproduced and adapted from [68] with permission of the publishers and the Oxford University Press). Asterix (*) denotes P < 0.01 for macrophages infected with 9-O-AcSA^high NO-resistant promastigotes versus de-O-acetylated susceptible promastigotes under similar conditions.