Abbasi Marjan, Kowalewska-Grochowska Kinga, Bahar Mohammad A, Kilani Ruhangiz T, Winkler-Lowen Bonnie, Guilbert Larry J
Departments of Family Medicine and Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
J Infect Dis. 2003 Aug 15;188(4):608-16. doi: 10.1086/377132. Epub 2003 Jul 31.
How the intracellular parasite Toxoplasma gondii causes placental inflammation and infects the fetus is unknown. By use of a culture model of primary human trophoblasts, we examined the consequences of infection by a virulent strain of T. gondii. Infection fractions (parasitophorous vacuoles per trophoblast nuclei) < or =0.9 were observed 1 day after challenge at an inoculum ratio of T. gondii to nuclei of 10. The culture content of infectious T. gondii increased 45-fold in 48 h. Two days after infection, almost 30% of trophoblast nuclei became apoptotic, and 30%-35% of nuclei were lost. Almost 90% of apoptotic nuclei were not adjacent to a parasitophorous vacuole, suggesting infection protected against apoptosis. However, there was no T. gondii-dependent accumulation of putative cytotoxic factors, such as tumor necrosis factor-alpha, that could mediate paracrine killing. Both mature and immature trophoblasts can be productively infected, and uninfected, but not infected, cells undergo apoptosis.
细胞内寄生虫刚地弓形虫如何引发胎盘炎症并感染胎儿尚不清楚。通过使用原代人滋养层细胞培养模型，我们研究了强毒株刚地弓形虫感染的后果。在以刚地弓形虫与细胞核10的接种比例进行攻击1天后，观察到感染分数（每个滋养层细胞核的寄生泡）≤0.9。感染性刚地弓形虫的培养物含量在48小时内增加了45倍。感染两天后，近30%的滋养层细胞核发生凋亡，30%-35%的细胞核丢失。几乎90%的凋亡细胞核不与寄生泡相邻，这表明感染可防止细胞凋亡。然而，不存在可介导旁分泌杀伤作用的如肿瘤坏死因子-α等假定细胞毒性因子的刚地弓形虫依赖性积累。成熟和未成熟的滋养层细胞均可被有效感染，未感染而非已感染的细胞会发生凋亡。
