Background: Maintenance immunosuppression is required for suppression of alloimmunity or allograft rejection. However, continuous use of immunosuppressants may lead to various side effects, necessitating the use of alternative immunosuppressive drugs. The early secreted antigenic target of 6 kDa (ESAT-6) is a virulence factor and immunoregulatory protein of mycobacterium tuberculosis (Mtb), which alters host immunity through dually regulating development or activation of various immune cells. ESAT-6 may be a potential alternative immunosuppressant that could be utilized to suppress allograft rejection although it remains unknown whether ESAT-6 actually regulates alloimmunity.
Methods: In this study, murine skin or heart allotransplantation was performed to determine the effects of ESAT-6 protein on allograft survival. Flow cytometric analyses were conducted to quantify CD4Foxp3 Tregs, while immunohistochemistry was carried out to observe allograft immunopathology. Western blotting was used to detect IĸBα/c-Rel signaling during Treg induction. Finally, CD4CD25 conventional T cells were cultured to induce Tregs and their proliferation.
Results: Here we found that ESAT-6 significantly extended murine skin and heart allograft survival, alleviated CD3 T cell infiltration and increased Foxp3 Tregs in an allograft. ESAT-6 augmented the percentage of CD4Foxp3 Tregs, whereas it decreased the frequency of Th1 and CD4/CD8 effector T cells in spleen and lymph nodes (LNs) posttransplantation. ESAT-6 also induced CD4Foxp3 Tregs from CD4CD25 T cells by activating IĸBα/c-Rel signaling pathway, whereas inhibition of c-Rel signaling blocked Treg induction. Moreover, it suppressed conventional CD4CD25 T cell proliferation in the absence of antigen-presenting cells (APCs), with an increase in IL-10 and decrease in IFN-γ production. On the other hand, it did not significantly alter DC maturation after allotransplantation.
Conclusion: Thus, ESAT-6 suppresses alloimmunity and inhibits allograft rejection by inducing CD4Foxp3 Tregs through IĸBα/c-Rel signaling pathway.
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http://dx.doi.org/10.3389/fimmu.2024.1529226 | DOI Listing |
PLoS One
January 2025
Transplant Group, La Paz University Hospital Health Research Institute (IdiPAZ), Madrid, Spain.
Background: Intestinal transplantation (ITx) represents the only curative option for patients with irreversible intestinal failure. Nevertheless, its rejection rate surpasses that of other solid organ transplants due to the heightened immunological load of the gut. Regulatory T-cells (Tregs) are key players in the induction and maintenance of peripheral tolerance, suggesting their potential involvement in modulating host vs.
View Article and Find Full Text PDFFront Immunol
January 2025
Section of Immunology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China.
Background: Maintenance immunosuppression is required for suppression of alloimmunity or allograft rejection. However, continuous use of immunosuppressants may lead to various side effects, necessitating the use of alternative immunosuppressive drugs. The early secreted antigenic target of 6 kDa (ESAT-6) is a virulence factor and immunoregulatory protein of mycobacterium tuberculosis (Mtb), which alters host immunity through dually regulating development or activation of various immune cells.
View Article and Find Full Text PDFKidney Int
February 2025
Transplantation & Clinical Virology, Department of Biomedicine, University of Basel, Basel Switzerland. Electronic address:
BK polyomavirus remains a vexing issue in kidney transplantation. There are no antiviral drugs, and solely reducing immunosuppression is recommended for management. However, evidence from randomized controlled studies lacks defining clearance of BK polyomavirus-DNAemia and/or nephropathy as a primary outcome.
View Article and Find Full Text PDFAm J Transplant
January 2025
Department of Gastrointestinal Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China; Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Chengdu, Sichuan Province, China. Electronic address:
Regulatory T cells (Tregs) has been shown to be involved in the induction of transplantation tolerance in numerous models. Our previous work demonstrated that METTL14 loss impaired Treg function and hindered the establishment of transplantation tolerance. However, the underlying mechanisms remain unclear.
View Article and Find Full Text PDFJ Plast Reconstr Aesthet Surg
November 2024
Yale School of Medicine, Division of Reconstructive and Plastic Surgery, New Haven, CT, USA. Electronic address:
Background: The long-term stability of allograft or native bone in facial vascularized composite allograft (fVCA) recipients is unclear. This study quantified long-term bone volume changes in facial transplants.
Methods: Computed tomography scans of eight fVCA recipients (2011-2023) were analyzed with Materialise Mimics.
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