Leishmania infantum: Infection of macrophages in vitro with promastigotes

Leishmania infantum: infection of macrophages in vitro with promastigotes. International Journal for. Parasitology 26: 619-622. Leishmania infantum promastigotes in axenic culture exhibit limited infectivity for mouse peritoneal macrophages (M(phi)) in vitro using standard culture conditions (37 degrees C; 95% air/5% CO2) compared to Leishmania donovani promastigotes which induce notable infections. The infectivity of logarithmic (log) and stationary (stat) phase promastigotes of L. infantum was enhanced by the addition of fresh homologous serum, but no amastigotes were observed after 4 days. Prolonged infections, including transformation and survival of intracellular amastigotes in BALB/c mouse and hamster resident peritoneal M(phi) and M(phi) cell line J774.G8 were obtained by incubating M(phi) for 48 h at 26 degrees C prior to standard culture. Enhanced infectivity was observed in a number of L. infantum strains subject to this transient thermal change. Copyright (C) 1996 Australian Society for Parasitology. Published by Elsevier Science Ltd.