Franke E D, McGreevy P B, Katz S P, Sacks D L
J Immunol. 1985 Apr;134(4):2713-8.
The ability of in vitro grown Leishmania promastigotes to resist lysis by complement and survive in undiluted human serum was related to the species of Leishmania and the growth phase in culture. Promastigotes from log phase cultures were always killed in undiluted serum, whereas survival of stationary phase promastigotes varied among species. All L. major and L. m. amazonensis were killed, while up to 30% of L.b. panamensis and 10% of L. donovani survived. Lysis of promastigotes by human serum was inhibited in heat-inactivated serum and EDTA-chelated serum, indicating that activation of complement was responsible for killing. Therefore, during growth in vitro, some strains of Leishmania promastigotes can undergo development from a complement-susceptible to -resistant stage. Stationary phase promastigotes of L.b. panamensis which survived in undiluted human serum were capable of subsequent growth in culture, and were also able to initiate infection in Mystromys albicaudatus. Organisms selected on the basis of complement resistance were more infective for M. albicaudatus than either log phase promastigotes or unselected promastigotes from stationary cultures. These data support the notion that the life cycle of Leishmania includes an infective stage promastigote which is generated during growth within the sandfly and which, on inoculation, is able to survive the potentially lethal effect of normal serum before uptake by host macrophages.
体外培养的利什曼原虫前鞭毛体抵抗补体溶解并在未稀释的人血清中存活的能力与利什曼原虫的种类及培养中的生长阶段有关。对数期培养物中的前鞭毛体在未稀释的血清中总是会被杀死，而稳定期前鞭毛体的存活情况因种类而异。所有的硕大利什曼原虫和亚马逊利什曼原虫亚种均被杀死，而巴拿马利什曼原虫亚种高达30%以及杜氏利什曼原虫10%的前鞭毛体存活了下来。人血清对前鞭毛体的溶解作用在热灭活血清和EDTA螯合血清中受到抑制，这表明补体的激活是造成杀伤的原因。因此，在体外生长过程中，一些利什曼原虫前鞭毛体菌株能够经历从补体敏感阶段到抗性阶段的发育过程。在未稀释的人血清中存活下来的巴拿马利什曼原虫亚种稳定期前鞭毛体能够在培养中继续生长，并且也能够在白尾匙鼠中引发感染。基于补体抗性选择出来的生物体对白尾匙鼠的感染性比对数期前鞭毛体或来自稳定期培养物的未选择前鞭毛体更强。这些数据支持了这样一种观点，即利什曼原虫的生命周期包括一个感染性前鞭毛体阶段，该阶段在前鞭毛体在沙蝇体内生长期间产生，并且在接种后，能够在被宿主巨噬细胞摄取之前在正常血清的潜在致死作用下存活下来。
