Effect of sodium stibogluconate and pentamidine on in vitro multiplication of Leishmania donovani in peritoneal macrophages from infected and drug‐treated BALB/c mice

Abstract

The in vitro antileishmanial activity of sodium stibogluconate (SSG) and pentamidine in peritoneal macrophages from three different groups of animals (i.e. normal, Leishmania donovani infected and drug-treated BALB/c mice) is reported. Peritoneal macrophages were extracted from all these animals and infected in vitro with L. donovani promastigotes. After 24 h, the infected macrophages (with amastigotes) were exposed to various concentrations of SSG (10–90 g/mL) and pentamidine (0.1–5.0 g/mL). The in vitro infection could he cured readily with 80 g/mL of SSG and 4 g/mL of pentamidine in macrophages from normal animals. But even higher dosages of these drugs added in vitro could not reduce the amastigote loads in macrophages from infected animals. In contrast, incubation in vitro of infected macrophages with very low dosages of these drugs (40 g/mL of SSG and 1.0/mL of pentamidine) could eliminate the parasites present within macrophages obtained from drug-treated animals. This was probably because the macrophages from drug-treated animals tackled the parasites themselves by their microbicidal mechanisms and the in vitro infection was tackled by the drug in vitro. This implies that a well-developed specific immunity in leishmaniasis helps in the antileishmanial activity of these drugs.