Fig. 2: Mechanisms of antagonizing the host immune response by T. gondii.
From: Exploring the potential of Toxoplasma gondii in drug development and as a delivery system
After invasion of the host cell, T gondii alters host signaling pathways and gene expression, antagonizing immune responses. STAT3 activated by IL-6 and IL-10 is associated with antagonizing host defense. T. gondii also directly activates STAT3 to antagonize the host immune response. T. gondii also upregulates SOCS3, which binds JAK-2 and inhibits the phosphorylation of STAT3. The depletion of SOCS3 enhanced T. gondii-induced STAT3 signaling, resulting in reduced levels of IL-12 and IFN-γ. Taken together, these results indicate that SOCS3 might have additional mechanisms to limit the phosphorylation of STAT3. In addition, T. gondii antagonizes IFN-γ production by interfering with NF-κB activation and STAT1 activation, which are inhibited by SOCS1.
