Leishmania major and Leishmania tropica: I the in vitro effects of an immunomodulator, S 2-Complex

Abstract

This study was undertaken to try to determine the possible anti-leishmanial activity of S 2-Complex, an organic complex of copper chloride, ascorbic acid, and nicotinamide. The promastigotes, axenic amastigotes, and intracellular amastigotes of both Leishmania major and Leishmania tropica were incubated with different concentrations of S 2-Complex. The EC 50 for each form was calculated. Results show that all forms of the parasites were dose dependently inhibited by S 2-Complex. The promastigotes of both parasites were the most resistant with highest EC 50 followed by axenic amastigotes. While intracellular amastigotes were the most sensitive with the lowest EC 50.These results indicate that S 2-Complex has a direct anti-leishmanial effect. When mice were treated with S 2-Complex or BCG for four days before harvesting the macrophages, and the macrophages infected with both L. major and L. tropica, they showed increased phagocytosis and increased parasite killing. The results of S 2-Complex were not statistically different from the immunomodulating agent BCG. These results indicate that S 2-Complex has an immunomodulating effect in addition to the direct anti-leishmanial effect.