Virulence-related gene wx2 of Toxoplasma gondii regulated host immune response via classic pyroptosis pathway

BACKGROUND: Toxoplasma gondii is known as the most successful parasite, which can regulate the host immune response through a variety of ways to achieve immune escape. We previously reported that a novel gene wx2 of T. gondii may be a virulence-related molecule. The objective of this study was to explore the mechanism of wx2 regulating host immune response. METHODS: The wx2 knockout strain (RH(wx2−/−) strain) and complementary strain (RH(wx2+/+) strain) were constructed by the CRISPR/Cas9 technique, and the virulence of the wx2 gene was detected and changes in pyroptosis-related molecules were observed. RESULTS: Compared with the wild RH and RH(wx2+/+) strain groups, the survival time for mice infected with the RH(wx2−/−) strain was prolonged to a certain extent. The mRNA levels of pyroptosis-related molecules of caspase-1, NLRP3, and GSDMD and et al. in mouse lymphocytes in vivo and RAW267.4 cells in vitro infected with RH(wx2−/−) strain increased to different degrees, compared with infected with wild RH strain and RH(wx2+/+) strain. As with the mRNA level, the protein level of caspase-1, caspase-1 p20, IL-1β, NLRP3, GSDMD-FL, GSDMD-N, and phosphorylation level of NF-κB (p65) were also significantly increased. These data suggest that wx2 may regulate the host immune response through the pyroptosis pathway. In infected RAW264.7 cells at 48 h post-infection, the levels of Th1-type cytokines of IFN-γ, Th2-type cytokines such as IL-13, Th17-type cytokine of IL-17 in cells infected with RH(wx2−/−) were significantly higher than those of RH and RH(wx2+/+) strains, suggesting that the wx2 may inhibit the host's immune response. CONCLUSION: wx2 is a virulence related gene of T. gondii, and may be involved in host immune regulation by inhibiting the pyroptosis pathway. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13071-022-05502-5.