Details

Autor(en) / Beteiligte

• Shastri, Anjali J
• Marino, Nicole D
• Franco, Magdalena
• Lodoen, Melissa B
• Boothroyd, John C
• Adams, J. H.

Titel

GRA25 is a novel virulence factor of Toxoplasma gondii and influences the host immune response

Ist Teil von

• Infection and immunity, 2014-06, Vol.82 (6), p.2595-2605

Ort / Verlag

United States: American Society for Microbiology

Erscheinungsjahr

2014

Quelle

Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals

Beschreibungen/Notizen

• The obligate intracellular parasite Toxoplasma gondii is able to infect a broad range of hosts and cell types due, in part, to the diverse arsenal of effectors it secretes into the host cell. Here, using genetic crosses between type II and type III Toxoplasma strains and quantitative trait locus (QTL) mapping of the changes they induce in macrophage gene expression, we identify a novel dense granule protein, GRA25. Encoded on chromosome IX, GRA25 is a phosphoprotein that is secreted outside the parasites and is found within the parasitophorous vacuole. In vitro experiments with a type II Δgra25 strain showed that macrophages infected with this strain secrete lower levels of CCL2 and CXCL1 than those infected with the wild-type or complemented control parasites. In vivo experiments showed that mice infected with a type II Δgra25 strain are able to survive an otherwise lethal dose of Toxoplasma tachyzoites and that complementation of the mutant with an ectopic copy of GRA25 largely rescues this phenotype. Interestingly, the type II and type III versions of GRA25 differ in endogenous expression levels; however, both are able to promote parasite expansion in vivo when expressed in a type II Δgra25 strain. These data establish GRA25 as a novel virulence factor and immune modulator.