Fig. 5: Protective efficacy of LmCen^−/− parasites against sand fly challenge in C57BL/6 mice.

a Schematic representation of the sand fly challenge procedure. b Ear lesion thickness was measured weekly for both LmCen^−/− immunized (Imm Chal) (n = 12) and non-immunized (Non-Imm Chal) (n = 14) mice after sand fly transmission. only 1 mouse out of 12 LmCen^−/− immunized-challenged has developed severe lesion. Results are represented as SEM, of 1 ear from each of the 12–14 mice per group and data pooled from two independent experiments. Statistical analysis was performed by Mann–Whitney two-tailed test (*p −0.02). c Photographs (left panel) & histology (H&E staining right panel) of representative ear of age-matched naïve, LmCen^−/− immunized (Imm Chal) & non- immunized (Non-Imm Chal) mice after 10 weeks post challenge from one of two independent experiments. Ear histology sections are representative of one mouse from each group of one of two independent experiments (n = 2). Arrow indicates inflammatory cells recruited area. Scale Bars: 100 μm. Scatter dot plots of parasite load in the challenged ear (d) and in the draining lymph node (e) of each LmCen^−/− immunized (Imm Chal) (n = 12) & non-Immunized (Non-Imm chal) (n = 14) mice. Parasite burden was determined by limiting dilution assay. Results are represented as geometric means with 95% Cl of total 12–14 mice in each group. Data are pooled from two independent experiments. Statistical analysis was performed by Mann–Whitney two-tailed test (****p < 0.0001).