Infection of placental trophoblasts by Toxoplasma gondii.
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.
Abbasi
Marjan
M
Departments of Family Medicine and Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
Kowalewska-Grochowska
Kinga
K
Bahar
Mohammad A
MA
Kilani
Ruhangiz T
RT
Winkler-Lowen
Bonnie
B
Guilbert
Larry J
LJ
D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D005260:Female; D006801:Humans; D010920:Placenta / Q000469:parasitology* / Q000473:pathology; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000469:parasitology; D014122:Toxoplasma / Q000502:physiology*; D014125:Toxoplasmosis, Congenital / Q000469:parasitology; D014327:Trophoblasts / Q000469:parasitology* / Q000473:pathology; D014709:Vero Cells