Fig. 3: Safety and non-pathogenicity characteristics of LmCen^−/− parasites.

a BALB/c; b STAT1 KO; c IFN-γ KO and d Rag2 KO mice were subcutaneously inoculated with indicated doses of LmWT or LmCen^−/− into the right hind footpad. a BALB/c mice (LmWT, n = 5) or (LmCen^−/−,n = 7) c IFN-γ KO mice (LmWT, n = 4) or (LmCen^−/−, n = 6), d Rag2 KO mice (LmWT, n = 6) or (LmCen^−/−, n = 6) were infected with 1 × 10⁷ of LmWT (Friedlin V9) or LmCen^−/− and b STAT1 KO mice were infected with 2 × 10⁸ of LmWT (Friedlin V9) (n = 4) or LmCen^−/−(n = 4) parasites. Following infection, footpad swelling was measured weekly by digital caliper. Parasite burden in infected footpad was measured at 5 weeks after infection in BALB/c (LmWT, n = 4) and (LmCen^−/−, n = 4), at 7 weeks in STAT1 KO (LmWT, n = 5) and (LmCen^−/−, n = 5) or at 15 weeks in IFN-γ KO (LmWT, n = 4) and (LmCen^−/−, n = 4) and at 15 weeks in Rag2 KO (LmWT, n = 6) and (LmCen^−/−, n = 6). For the lesion development studies shown in a–d (left panels) as SEM a, c and d and as SD b and for parasite burden studies shown in a–d (right panel) as mean ± SEM a, c and d and as mean ± SD b, unpaired two-tailed t-test (*p −0.04, **p −0.009, ***p < 0.0009, ****p < 0.0001). The differences in footpad swelling were statistically significant at all time points after the initial observation of the lesion. Experiments representing a, b and c performed twice; and experiment representing d performed only one time. e Schematic representation of the DXM treatment. f Photographs of one representative ear of LmWT infected (group-1) (n = 6), LmCen^−/− (group-2) (n = 6) and (LmCen^−/−+DXM) (group-3) (n = 12) mice from one of two independent experiments. Scatter dot plots of parasite load in the infected ear g and in the draining lymph node (dLN) h of each LmWT (n = 6) and LmCen^−/− (n = 6) and LmCen^−/−+DXM (n = 12) immunized mice. Parasite burden was determined by limiting dilution assay. Results are expressed as mean ± SEM and data pooled from two independent experiments. Statistical analysis was performed by unpaired two-tailed t-test (**p −0.004, ***p −0.0006).