Intracellular behaviour of Leishmania enriettii within murine macrophages.

Both promastigotes and amastigotes of Leishmania enriettii were readily ingested by mouse peritoneal macrophages (MPM). Promastigotes after their entry within MPM were rapidly immobilized and their multiplication was never observed. Microscopic examination revealed that ingested promastigotes were degraded with MPM. Nonmotile amastigotes of L. enriettii taken up by MPM, on the other hand, multiplied intracellularly and eventually destroyed the infected cells.