GP63 confers virulence to <i>L</i>. <i>mexicana</i> Δ<i>cpb</i>.

<p>Stationary phase <i>L</i>. <i>mexicana</i> (WT, Δ<i>cpb</i>, Δ<i>cpb</i>+<i>cpb</i> and Δ<i>cpb</i>+<i>GP63</i>) promastigotes were incubated in the presence of 20% human serum for 30 min, stained with a fixable viability dye, and then subjected to flow cytometry <b>(A)</b>. Mice were challenged with 5x10⁶ late-stationary phase <i>L</i>. <i>mexicana</i> (WT, Δ<i>cpb</i>, Δ<i>cpb</i>+<i>cpb</i> and Δ<i>cpb</i>+<i>GP63</i>) promastigotes that were injected subcutaneously into the hind footpad. Disease progression was monitored at weekly intervals, by measuring the thickness of the infected footpad and the contralateral uninfected footpad. <b>(B)</b>. Parasite burden was obtained by limiting dilution assay from infected homogenized footpads 9 weeks after inoculation <b>(C)</b>. Human serum lyses were performed in two independent experiments and six mice per group were used for the determination of lesion formation and parasite burden. Each data point represents the average ± SEM of 6 mice per group, and statistical significance was denoted by * p≤0.01, and *** p≤0.0001.