Trichinella spiralis cystatin, TsCstN, modulates STAT4/IL-12 to specifically suppress IFN-γ production

We have previously identified a cystatin, TsCstN, derived from the L1 stage of Trichinella spiralis and have shown that this protein is internalised in macrophages. Here we sought to address if this macrophage-TsCstN interaction could alter downstream T-cell priming. Using LPS-primed macrophages to stimulate T-cells in a co-culture system with or without TsCstN we assessed the resultant T-cell outcomes. IFN-gamma, both protein and mRNA, but not IL-17A was negatively regulated by inclusion of TsCstN during macrophage priming. We identified a cell-cell contact independent change in the levels of IL-12 that led to altered phosphorylated STAT4 levels and translocation. TsCstN also negatively regulated the autonomous response in the myotubule cell line, C2C12. This work identifies a potential pathyway for L1 larvae to evade protective Th1 based immune responses and establish muscle-stage T. spiralis infection.

Automated summary

This study investigated the impact of TsCstN derived from Trichinella spiralis L1 stage on macrophage-T cell interaction and immune responses. The results showed that TsCstN negatively regulated IFN-gamma production in macrophages, but not IL-17A, as well as affected IL-12 levels and the autonomous response in myotubule cells. This work reveals a potential pathway for L1 larvae to evade immune responses and establish infection.