FIG. 6.
Evaluation of protection against visceral leishmaniasis in BALB/c mice after immunization with the purified 115-kDa serine protease. At different time points postimmunization, parasite burdens in the livers and spleens of mice challenged with 5 × 105 or 5 × 108 virulent L. donovani promastigotes were quantified in Giemsa-stained preparations of impression smears. The results are expressed as the number of parasites per organ. Each experiment was performed at least three times, and the results are means ± standard deviations. Asterisks indicate significance levels (*, P < 0.05; **, P < 0.01).