Unterdrückung der MHC Expression in Hornhautzellen um die Abstoßung bei einer allogenen Transplantation zu verhindern: Experimentelle Untersuchung im Mausmodel
Zusammenfassung der Projektergebnisse
Cornea transplantation is the most widespread type of transplantation. Keratoplasties profit from the usual avascularization of the cornea which confers it an immunological privilege despite of mismatches at the human leukocyte antigen (HLA) loci. However, in case of re-transplantation or vascularization of the graft bed, the graft becomes more susceptible to immune rejection. Previously, we have demonstrated the possibility to silence MHC class I and II expression in different cell types including CD34+ cells, fibroblasts and endothelial cells and showed that the engineered cells were protected against humoral and cellular immune responses in vitro and in vivo. Hence, this study aimed at the evaluation of the effect of MHC silencing class I and II on cornea in preventing allogeneic immune responses. For this purpose, we have established a fully MHC incompatible cornea transplantation mouse model. Corneas of C3H mice were transplanted into Balb/cJ recipients. In addition, a protocol for the transduction of the corneal tissue with lentiviral vectors encoding for shRNAs targeting either β2-microglobulin (shβ2m) or the alpha chain of MHC class II molecules (shHE2a) was established. The grafts were monitored for a maximal period of nine weeks. A knockdown of MHC class I expression by up to 70% in the corneas was achieved. Also, the expression of shHE2a prevented the upregulation of MHC class II in the corneas. The transduction protocol of the corneas did not impair the integrity of the tissue as shown by comparison of nontransduced and MHC-silenced corneas after two days in culture. After transplantation, MHC-silenced corneas induced lower secretion of pro-inflammatory cytokines such as MCP-1 and IL-1β as well as significantly lower levels of IL-17A. In addition, silencing MHC class I and II expression corneas showed lower T-cell infiltration than the MHC expressing controls. Remarkably, in comparison to corneas expressing shNS, MHC class I silenced corneas induced significantly lower production of IgGA, IgGM and IgG1. Furthermore, sera of animals transplanted with MHC class II silenced corneas exhibited significantly lower levels of IgG, IgG2a and IgG2b. In conclusion, MHC silencing contributed to decrease the strength of the allogeneic immune response after MHC incompatible cornea transplantation even in the absence of immunosuppression. Hence, MHC silencing may contribute to protect tissues and organs against immune rejection and to abrogate or decrease the need for immunosuppression.
Projektbezogene Publikationen (Auswahl)
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A future with less HLA: potential clinical applications of HLA-universal cells. Tissue Antigens. 2015 Jun;85(6):443-9
Figueiredo C, Blasczyk R
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Silencing MHC expression in the cornea to prevent the risk of graft rejection. Transfus Med Hemother. 2015 Sep; 42(suppl 1):1-66. Abstract at the 48. Jahreskongress der Deutschen Gesellschaft für Transfusionsmedizin und Immunhämatologie (DGTI), 15-18th September 2015, Basel, Switzerland
Börger AK, Mueller C, Wittig D, Blasczyk R, Engelmann K, Figueiredo C
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RNA interference as a tool to reduce the risk of rejection in Cell-based therapies. RNA Interference. INTECH. 2016 April;311-324
Figueiredo C, Blasczyk R
