Genetic engineering of Tregs to further improve their function in preventing transplant rejection
Human Tregs have been transduced with a lentiviral vectosr containing a chimeric antigen receptor (CAR) specific for an HLA class I molecule expressed by the transplant. We have shown that in vivo CAR-Tregs were superior compared to polyclonal Tregs. To further improve the function of the Tregs, the construct containing the CAR has been further manipulated to contain: 1. An additional gene encoding for IL-10; and 2. The CD28 co-stimulatory endodomain has been substituted with genes encoding for other molecules such as OX-40, 4-1BB, CD27, ICOS and death receptor 3 (DR3). The different constructs have been generated, Tregs have been transduced and the initial tests have been performed in vitro. Their function in vitro and then in vivo needs to be evaluated using suppression assays and humanised mouse models, respectively.