FIG. 3.

Infection rates of the L. donovani BT1 null mutant (BT1 ko) in BALB/c mice. Late-stationary-phase L. donovani promastigote cells (5 × 10⁷), either wild-type (WT) (black box), BT1 null mutant (hatched box), or BT1 null mutant retransfected with an episomal BT1 gene (BT1 ko-BT1) (white box) were injected i.v. into the tail veins of BALB/c mice. (A) L. donovani cells were counted 4 weeks postinfection by impression smears of the liver and staining with Giemsa. Results are averages for three independent experiments with five mice per group. (B) Similar numbers of animals were infected with the L. donovani wild type and the BT1 null mutant expressing the firefly luciferase (LUC) gene. Mice were sacrificed 4 weeks postinfection, and luciferase activity was measured in the liver and the spleen. LDU, L. donovani units; RLU, relative luciferase units.