The downregulation of Tapasin in dendritic cell regulates CD8+ T cell autophagy to hamper hepatitis B viral clearance in the induced pluripotent stem cell‐derived hepatocyte organoid

Abstract Tapasin, a crucial molecular chaperone involved viral antigen processing and presentation, plays an important role in antivirus immunity. However, its impact on T cell differentiation in the context of virus clearance remains unclear. In this study, we employed induced pluripotent stem cells to differentiate into hepatocyte‐like cell, which were subsequently inserted to the inverted colloidal crystal scaffolds, thus establishing a hepatocyte organoid (HO). By inoculating hepatitis B virus (HBV) particles in the system, we successfully engineered a robust in vitro HBV infection model for at least 3 weeks. Furthermore, we aimed to explore the effects of lentivirus‐mediated short hairpin RNA (shRNA) targeting human Tapasin on the differentiation and antiviral function of CD8 + T cells. Specifically, we transfected dendritic cells (DCs) with Tapasin‐shRNA and cocultured with T cells. The results demonstrated that Tapasin‐shRNA transfected DCs effectively suppressed T cell proliferation and impeded HBV‐specific cytotoxic T lymphocyte responses. Our investigation also revealed the role of mTOR pathway activation in reducing autophagy activity within CD8 + T cells. Expressions of autophagy‐related proteins, beclin‐1, LC3II/LC3I were decreased and PI3K/AKT/mTOR activity was increased in Tapasin‐shRNA group. Collectively, our findings elucidate that shRNA targeting the Tapasin gene within DCs inhibits T cell differentiation by reducing autophagy activity to hamper viral clearance in the HBV‐infected HO.