Abstract

Toxoplasma gondii is an obligate intracellular parasite that infects over one-third of the global population, and it can cause significant morbidity and mortality among the newborn and the immunocompromised. Upon entry, it secretes an arsenal of organelles to commandeer host functions. Taken together, in vitro and in vivo data suggest that rhoptry protein 13 (ROP13) expression upregulates the anti-inflammatory IL-33/ST2 pathway in 3T3 cells by promoting sensitivity to type 2 cytokines such as IL-4 and IL-13 while concomitantly antagonising pro-inflammatory cytokines, namely IFN γ and IL-12. ROP13 appears to be involved in maintaining the delicate pro and anti-inflammatory balance necessary for effective management and perpetuation of parasite burden, reflecting an age-old adage about parasitism: “parasite depends on host immunity for its survival as much as the host.”