Targeting stem cell-derived viral antigen-specific T lymphocytes for HBV immunotherapy

Abstract

Abstract Adoptive cell transfer (ACT) of hepatitis B virus (HBV)-specific CD8+ cytotoxic T lymphocytes (CTLs) is a promising treatment for chronic HBV infection. Naive or central memory T cell-derived effector CTLs known as “highly reactive” cells are optimal populations for cell-based therapies. However, such ACT is often not feasible due to difficulties in obtaining sufficient numbers of CTLs from patients. Pluripotent stem cells (PSCs) have the capacity to be reprogrammed into functional viral antigen (Ag)-specific CTLs, which have a potential to be used for ACT-based immunotherapy. However, the optimal approach to differentiate viral Ag -specific CTLs from PSCs remains unclear. In this study, we generated HBV-specific CTLs from induced PSCs (iPSCs), i.e., iPSC-CTLs, and utilized a mouse model of chronic HBV infection to test ACT of iPSC-CTLs for HBV immunotherapy. Murine iPSCs that genetically modified with HBV-specific T cell receptor (TCR) were co-cultured with OP9 cell line expressing Notch ligands Delta-like 1 and 4 (OP9-DL1/DL4 cell) for a week and adoptively transferred into recipient C67BL/6 mice for in vivo development. The combination of Notch signaling and incorporation of HBV-specific TCR genes in iPSCs drove the development of HBV-specific iPSC-CTLs. In addition, In a mouse model of chronic HBV infection in which the HBV viral genome is delivered into the mouse liver through hydrodynamic injection, HBV-specific iPSC-CTLs infiltrated into liver tissue, and inhibited HBV replication after ACT. These results confirm that ACT of viral Ag-specific iPSC-CTLs can substantially suppress HBV replication, and indicate that stem cell-derived highly reactive viral Ag-specific CTLs may be used for HBV immunotherapy.