A Cell Culture System for Study of the Development of Toxoplasma gondii Bradyzoites

LOUIS M. WEISS, DENISE LAPLACE, PETER M. TAKVORIAN, HERBERT B. TANOWITZ, ANN CALI, MURRAY WITTNER

Research output: Contribution to journalArticlepeer-review

132 Scopus citations

Abstract

ABSTRACT. Toxoplasma gondii is a ubiquitous apicomplexan parasite and a major opportunistic pathogen under AIDS‐induced conditions, where it causes encephalitis when the bradyzoite (cyst) stage is reactivated. A bradyzoite‐specific Mab, 74.1.8, reacting with a 28 kDa antigen, was used to study bradyzoite development in vitro by immuno‐electron microscopy and immunofluorescence in human fibroblasts infected with ME49 strain T. gondii. Bradyzoites were detected in tissue culture within 3 days of infection. Free floating cyst‐like structures were also identified. Western blotting demonstrated the expression of bradyzoite antigens in these free‐floating cysts as well as in the monolayer. Bradyzoite development was increased by using media adjusted to pH 6.8 or 8.2. The addition of γ‐interferon at day 3 of culture while decreasing the total number of cysts formed prevented tachyzoite overgrowth and enabled study of in vitro bradyzoites for up to 25 days. The addition of IL‐6 increased the number of cysts released into the medium and increased the number of cysts formed at pH 7.2. Confirmation of bradyzoite development in vitro was provided by electron microscopy. It is possible that the induction of an acute phase response in the host cell may be important for bradyzoite differentiation. This system should allow further studies on the effect of various agents on the development of bradyzoites.

Original languageEnglish (US)
Pages (from-to)150-157
Number of pages8
JournalJournal of Eukaryotic Microbiology
Volume42
Issue number2
DOIs
StatePublished - Mar 1995

Keywords

  • Bradyzoite
  • Toxoplasma gondii
  • cyst
  • in vitro development

ASJC Scopus subject areas

  • Microbiology

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