Fig. 1

Induction of protective anti-M. leprae responses by recombinant antigens formulated in GLA-SE. In a mice were injected subcutaneously with antigens/GLA-SE at biweekly intervals, for a total of three immunizations. One month after the last immunization mice were infected with 1 × 10⁴ M. leprae in each foot, and bacterial burdens determined 12 months later. Results are shown as mean and s.e.m. Mann–Whitney test was used to calculate p-values between each group; n = 7 per group. In b, mice were injected, or not, with BCG vaccine then 1 month later were subsequently injected subcutaneously with LepVax (at biweekly intervals if immunized more than once). Serum and spleens were collected 1 month after the final immunization to determine antigen-specific immune responses Top panel, LEPF1-specific serum IgG1 and IgG2c titers were determined by ELISA. Middle and bottom panels, single-cell suspensions were prepared from each spleen and incubated with 10 μg/ml indicated protein (BCG = BCG lysate; MLCS = M. leprae cell sonicate), then culture supernatants collected 72 h later and IFNγ content determined by ELISA. Responses were corrected by the subtraction of the IFNγ concentration observed in the wells of unimmunized mice. Results are shown as mean and s.e.m; n = 5 per group. Data are representative of two independent experiments. In c, mice were immunized with a mixture of GLA-SE and either recombinant antigens represented in LepVax or with LepVax (either two or three times at biweekly intervals), or with heat-killed M. leprae (HKML) alone (no exogenous adjuvant added). One month after the last immunization mice were infected with 1 × 10⁴ M. leprae in each foot, and bacterial burdens determined 12 months later. Results are shown as mean and s.e.m. Mann–Whitney test was used to calculate p-values between each group; n = 10 per group. *p-value < 0.05 and **p-value < 0.01 versus unimmunized control