Figure 6. The SMase activity alone was sufficient to restore virulence in iscl⁻.

(A–B) Bone marrow-derived Mφs from BALB/c mice were infected by stationary phase promastigotes (•: WT, ○: iscl⁻, ▾: iscl⁻/+HA-ISCL, ▪: iscl⁻/+CnISC1, □: iscl⁻/+HA-BcSMase, ⧫: iscl⁻/+5′HASPb-BcSMase-HA, ▵: WT+activated Mφs) at a ratio of 15 parasites per Mφ. Percentages of infected Mφs (A) and the number of parasites in 100 Mφs (B) were recorded. (C–D) BALB/c mice were infected in the footpads with day 3 stationary promastigotes (•: WT, ○: iscl⁻, ▾: iscl⁻/+HA-ISCL, ▵: iscl⁻/+HA-BcSMase, ▪: iscl⁻/+5′HASPb-BcSMase-HA, □: iscl⁻/+CnISC1) at 1×10⁶ parasites per mouse (5 mice per group). Lesion sizes were measured with a caliper (C) and parasite numbers in infected footpads were determined by the limiting dilution assay (D). Error bars represent standard deviations from 2 independent experiments.