Combination of a conditioning by cyclophosphamide and IL-2 allows suppressive T cells to rescue scurfy mice after disease onset
Transcriptomic analysis reveal a lasting restoration of Treg identity in FOXP3-transduced scurfy cells – even an inflammatory environment
Immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome is caused by mutations in FOXP3, which lead to the loss of function of regulatory T cells (Treg) and the development of autoimmune manifestations early in life. The selective induction of a Treg program in autologous CD4+ T cells by FOXP3 gene transfer is a promising approach for curing IPEX. We have established a novel in vivo assay of Treg functionality, based on adoptive transfer of these cells into scurfy mice (an animal model of IPEX) and a combination of cyclophosphamide conditioning and interleukin-2 treatment. This model highlighted the possibility of rescuing scurfy disease after the latter's onset. By using this in vivo model and an optimized lentiviral vector expressing human Foxp3 and as a reporter a truncated form of the 5 low-affinity nerve growth factor receptor (DLNGFR), we demonstrated that the adoptive transfer of FOXP3-transduced scurfy CD4+ T cells enabled the long-term rescue of scurfy autoimmune disease. The efficiency was similar to that seen with wild-type Treg. After in vivo expansion, the converted CD4FOXP3 cells recapitulated the transcriptomic core signature for Treg. These findings demonstrate that FOXP3 expression converts CD4+ T cells into functional Treg capable of controlling severe autoimmune disease.