Induction of mitotic S-phase of host and neighboring cells by Toxoplasma gondii enhances parasite invasion

Mark D. Lavine, Gustavo Arrizabalaga

Research output: Contribution to journalArticle

24 Scopus citations


The intracellular parasite Toxoplasma gondii extensively modifies its host cell so as to efficiently grow and divide. Among these cellular changes, T. gondii alters the cell cycle of host cells it has invaded. We found that T. gondii affects the cell cycle of not only the cells it directly invades, but neighboring cells as well. Both direct invasion by T. gondii and exposure to filtered medium from cultures of T. gondii-infected cells (conditioned medium) caused normally quiescent fibroblasts to enter S-phase. T. gondii has been shown to attach to and invade S-phase host cells more readily, and we found that conditioned medium increased the rate of invasion of T. gondii into new host cells. Thus it appears that T. gondii directly releases, or induces parasitized host cells to release, a factor that induces neighboring cells to enter S-phase, allowing more rapid invasion by extracellular T. gondii and providing a possible selective advantage for the parasite.

Original languageEnglish (US)
Pages (from-to)95-99
Number of pages5
JournalMolecular and Biochemical Parasitology
Issue number1
StatePublished - Mar 1 2009



  • BrdU
  • Cell cycle
  • Invasion
  • S-phase
  • Toxoplasma

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology

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