Constitutive upregulation of transcription factors underlies permissive bradyzoite differentiation in a natural isolate of Toxoplasma gondii.

Abstract

Toxoplasma gondii is a widespread protozoan that chronically infects ~30% of the world's population. T. gondii can differentiate between the fast-growing life stage that causes acute infection and the slow-growing stage that persists in the host for extended periods of time. The slow-growing stage cannot be eliminated by the host immune response or currently known antiparasitic drugs. Studies on the slow-growing stage have been limited due to the limitations of in vivo experiments and the challenges of in vitro manipulation. Here, we characterize a natural isolate of T. gondii, which constitutively expresses factors that drive development and that is permissive to convert to the slow-growing stage under stress conditions in vitro. The strain presents a novel in vitro model for studying the chronic phase of toxoplasmosis and identifying new therapeutic treatments for chronic infections.