FIG 1.

Phagocytosis rate and infectivity of WT and live attenuated parasites in BMDM. BMDM were infected with opsonized WT L. donovani parasites, live attenuated parasites (Ldp27^−/− or LdCen^−/−) or gene-complemented add-back parasites (Ldp27^−/−AB, LdCen^−/−AB) (5:1, parasite to macrophage ratio). Intracellular parasite numbers were visualized by Giemsa staining and estimated microscopically at 6 h, 24 h, 48 h, and 72 h postinfection. (A and B) The infection efficiency (percentage of infected cells) (A) and intracellular growth (parasites per infected cell) (B) were recorded. To measure parasite load in these cultures, a minimum of 300 macrophages were counted. The data represent the means ± standard deviations of three independent experiments that all yielded similar results. *, P < 0.05; **, P < 0.005.