Tissue-repair regulatory T cells (trTregs) comprise a specialized cell subset essential for tissue homeostasis and repair. While well-studied in sterile injury models,their role in infection-induced tissue damage and antimicrobial immunity is less understood. We investigated trTreg dynamics during acute Trypanosoma cruzi infection,marked by extensive tissue damage and strong CD8+ immunity. Unlike sterile injury models,trTregs significantly declined in secondary lymphoid organs and non-lymphoid target tissues during infection,correlating with systemic and local tissue damage,and downregulation of function-associated genes in skeletal muscle. This decline was linked to decreased systemic IL-33 levels,a key trTreg growth factor,and promoted by the Th1 cytokine IFN-γ. Early recombinant IL-33 treatment increased trTregs,type 2 innate lymphoid cells,and parasite-specific CD8+ cells at specific time points after infection,leading to reduced tissue damage,lower parasite burden,and improved disease outcome. Our findings not only provide novel insights into trTregs during infection but also highlight the potential of optimizing immune balance by modulating trTreg responses to promote tissue repair while maintaining effective pathogen control during infection-induced injury. Author summaryDuring Chagas’ disease,caused by the protozoan Trypanosoma cruzi,severe organ damage is generated by the interplay between the parasite and the immune response. In our investigation,we examined the role of tissue-repair regulatory T cells (trTregs) during the acute phase of T. cruzi infection in mice. Surprisingly,we observed a reduction in trTregs at the peak of tissue damage,contrary to their usual accumulation after injury in other contexts. This decline aligned with decreased levels of interleukin-33,a critical factor for trTreg survival,and was promoted by the effector cytokine IFN-γ. Administering interleukin-33 at early infection times not only boosted trTregs but also expanded other reparative and antiparasitic immune cells. Consequently,these treated mice exhibited reduced damage and lower parasite levels in tissues. Our findings provide new insights into how trTreg function during infection-related injury,paving the way for strategies that balance the immune response to support tissue repair without weakening the body’s ability to fight the infection. This approach could have broader implications for treating infectious diseases and conditions involving tissue damage.
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