Partial anaerobiosis induces infectivity of Leishmania infantum promastigotes

Leishmania infantum stationary-phase promastigotes could acquire infectivit y via preincubation in a partially anaerobic medium (95% air/5% CO2) for 16 h before the infection, whereas promastigotes were efficiently destroyed w hen no CO2 was present. Incubation of L. infantum promastigotes with additi onal glucose (20 and 50 mM) greatly increased infection parameters in the a bsence of CO2; this is consistent with a "reverse Pasteur effect." Results showed that culture at 33 degrees C permitted survival and amastigote multi plication (a nearly 10-fold increase in amastigotes as compared with those observed in 37 degrees C cultures). This finding was obtained with the two strains of L. infantum tested (Doba and PB75).