Infection with Toxoplasma gondii bradyzoites has a diminished impact on host transcript levels relative to tachyzoite infection

Infect Immun. 2007 Feb;75(2):634-42. doi: 10.1128/IAI.01228-06. Epub 2006 Nov 6.

Abstract

Toxoplasma gondii, an intracellular pathogen, has the potential to infect nearly every warm-blooded animal but rarely causes morbidity. The ability for the parasite to convert to the bradyzoite stage and live inside slow-growing cysts that can go unnoticed by the host immune system allows for parasite persistence for the life of the infected host. This intracellular survival likely necessitates host cell modulation, and tachyzoites are known to modify a number of signaling cascades within the host to promote parasite survival. Little is known, however, about how bradyzoites manipulate their host cell. Microarrays were used to profile the host transcriptional changes caused by bradyzoite infection and compared to those of tachyzoite-infected and uninfected hosts cells 2 days postinfection in vitro. Infection resulted in chemokine, cytokine, extracellular matrix, and growth factor transcript level changes. A small group of genes were specifically induced by tachyzoite infection, including granulocyte-macrophage colony-stimulating factor, BCL2-related protein A1, and interleukin-24. Bradyzoite infection yielded only about half the changes seen with tachyzoite infection, and those changes that did occur were almost all of lower magnitude than those induced by tachyzoites. These results suggest that bradyzoites lead a more stealthy existence within the infected host cell.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cells, Cultured
  • Chemokines / biosynthesis
  • Chemokines / genetics
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Extracellular Matrix / genetics
  • Extracellular Matrix / metabolism
  • Fibroblasts / parasitology*
  • Gene Expression Regulation*
  • Granulocyte-Macrophage Colony-Stimulating Factor / biosynthesis
  • Granulocyte-Macrophage Colony-Stimulating Factor / genetics
  • Humans
  • Intercellular Signaling Peptides and Proteins / biosynthesis
  • Intercellular Signaling Peptides and Proteins / genetics
  • Interleukins / biosynthesis
  • Interleukins / genetics
  • Minor Histocompatibility Antigens
  • Oligonucleotide Array Sequence Analysis
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Toxoplasma / growth & development*
  • Toxoplasma / immunology
  • Toxoplasma / pathogenicity*

Substances

  • BCL2-related protein A1
  • Chemokines
  • Cytokines
  • Intercellular Signaling Peptides and Proteins
  • Interleukins
  • Minor Histocompatibility Antigens
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • interleukin-24
  • Granulocyte-Macrophage Colony-Stimulating Factor