Unleashing Synergistic T Cell Power: Novel Insights into Cooperative Killing of Virus-Infected Hepatocytes by Conventional and Auto-Aggressive CD8 T Cells
ECEIZA A. 1, DUDEK M. 1, WOHLLEBER D. 1, KNOLLE P. 1
1 Institute of Molecular Immunology, School of Medicine, Technical University of Munich, Munich, Germany
Background and Aims: Hepatitis B virus (HBV) infections in the liver are typically cleared by the adaptive immune system. However, the limited presence of virus-specific CD8 T cells at the infection site poses challenges. Recently, auto-aggressive T cells, a novel form of metabolic T cell activation, were discovered in nonalcoholic steatohepatitis (NASH). However, their role in viral liver infections remains unknown. Therefore, the aim of this project is to investigate the relevance of auto-aggressive T cells in clearing virus-infected hepatocytes, providing insights into HBV clearance in the absence of high numbers of virus-specific T cells.
Methods: To assess the synergistic engagement of antigen-specific CD8 T cells with auto-aggressive CD8 T cells in killing virus-infected hepatocytes, we employed time-lapse cytotoxicity assays measuring cell impedance. Co-cultures of primary murine hepatocytes were established with conventional effector CD8 T cells and auto-aggressive CD8 T cells. By comparing antigen-specific killing with auto-aggressive killing of hepatocytes, we determined their respective contributions.
Results: As expected, antigen-specific CD8 T cells efficiently eliminated virus-infected hepatocytes. Additionally, auto-aggressive T cell mediated killing resulted in antigen-independent hepatocyte elimination at a high effector-to-target ratio (> 1:10). Notably, co-incubation of cytotoxic effector CD8 T cells and auto-aggressive CD8 T cells at ratios, that individually would not induce hepatocyte killing, led to efficient elimination of hepatocytes. Furthermore, we identified soluble factors secreted by conventional T cells that triggered auto-aggression in CD8 T cells.
Conclusion: Our findings demonstrate the synergistic effect of cytotoxic CD8 T cells and auto-aggressive CD8 T cells in effectively eliminating virus-infected hepatocytes. This discovery uncovers innovative modes of cooperation among T cells with effector functions. Future experiments will characterize how conventional CD8 T cells engage auto-aggressive CD8 T cells to elicit a synergistic T cell power to kill virus-infected hepatocytes.