Effects of Promastigote Growth Phase, Frequency of Subculture, and Host Age on Promastigote-initiated Infections with Leishmania donovani in the Golden Hamster*†

摘要: SYNOPSIS Promastigotes of Leishmania donovani, 3S strain, were cultured from homogenized infected hamster spleen incubated at 25 C in a particle-free modification Tanabe's (1923) medium, and subcultured this medium 1 to 4 times. Promastigotes inoculated intracardially golden hamsters (Mesocricetus auratus). Promastigotes that frequently by transfer log phase growth retained their infectivity for hamsters, as assayed numbers amastigotes the liver 16 days post infection. infrequently stationary declined infectivity. The extent decline was roughly proportional length incubation periods primary culture plus 1st subculture. Promastigotes harvested significantly less infective than those growth, found after lower, times death longer, when organisms used infect hamsters. The age time inoculation affect apparent promastigotes or 2nd subculture. When weanling (age weeks), juvenile 8 weeks) adult 24 32 received same promastigotes, weanlings had highest days, shortest death, 3 groups; juveniles intermediate between adults; adults lowest parasites longest host. Differences statistically significant only adults. Responses infection with could be rendered indistinguishable if on basis 105 per g host body weight.