Tissue-specific cells generated to predict xenogeneic immune responses demonstrate that SLA-downregulated kidney proximal tubular epithelial cells are low immunogenic : [Preprint]

Patients with kidney failure depend on transplantation as the only curative option. Xenotransplantation re-emerged as a promising alternative to enlarge the available organ pool. However, the success of xenotransplantation depends on the design and selection of specific genetic modifications and on the development of robust assays allowing for a precise assessment of tissue-specific immune responses. Nevertheless, cell-based assays are often compromised by the low proliferative capacity of primary cells. Proximal tubular epithelial cells (PTECs) play a crucial role in kidney function. Here, we immortalized PTEC (imPTEC) by overexpression of simian virus 40 T large antigen. imPTEC showed typical morphology, phenotype, and functionality, but maintained steady cell cycling rates. Furthermore, SLA class I and class II transcript levels were reduced by up to 85% after transduction with lentiviral vectors encoding for shRNAs targeting β2-microglobulin and the class II transactivator. This contributed to reduce xenogeneic T-cell cytotoxicity (P = 0.0069) and decrease pro-inflammatory cytokine secretion such as IL-6 and IFN-γ. This study showed the feasibility to generate highly proliferative renal tubular cells and the development of tissue-specific immunomonitoring assays. Silencing SLA expression on PTEC demonstrated to be an effective strategy to prevent xenogeneic cellular immune responses and may strongly support graft survival after xenotransplantation.