Evaluation of the Anti-Leishmanial Effect of Recombinant Clostridium α-Toxin

Leishmaniasis is an infectious disease common in tropical and subtropical regions caused by the genus Leishmania, which is transmitted by the bite of female sandflies. In this study, we evaluate the anti-leishmanial effect of recombinant Clostridium α-toxin protein alone and the combination with glucantime through in vitro and in vivo.

Production, expression, and purification of recombinant α-toxin were evaluated by SDS-PAGE and Western blotting techniques. The antileishmanial activities of the purified α-toxin plus and without glucantime were examined in vitro and in vivo.

The results indicated successful expression of α-toxin as a 48 kDa band on SDS-PAGE and Western blot methods. Also, evaluation of α-toxin IC₅₀ showed the strong fatal effect of it, and glucantime on medium proliferated Leishmania promastigotes at lower concentrations compared with glucantime or α-toxin alone. Moreover, in vivo surveys showed that at the end of treatment courses, the mean of lesion size diminished in glucantime plus α-toxin treated mice versus negative control groups (p < 0.001). Also, there was a significant difference in the parasite burden of the spleen and liver of the control versus the test groups (p < 0.001).

The results showed recombinant α-toxin has synergistic effects with glucantime in destroying Leishmania parasites.