A method for the purification of Leishmania promastigotes from infected phlebotomine sandflies.

We describe a method for the purification of Leishmania promastigotes, isolated from infected sandflies (Lutzomyia longipalpis) using a discontinuous density centrifugation gradient (Percoll/Homem). The sandflies, infected seven days previously with Leishmania donovani chagasi or Leishmania mexicana mexicana from culture, were homogenized and centrifuged on a Percoll discontinuous gradient. Five interface bands were formed, and most of the promastigotes settled out at the interface between the (30% and 40%) Percoll concentrations. An extraction of 3.5 x 10(4) promastigotes from 90 female flies was achieved using this technique.