Single-cell atlas reveals characteristic changes in intrahepatic HBV-specific leukocytes

Abstract

ABSTRACT In the progression of liver disease, various metabolic disorders and inflammatory factors cause dysfunction of intrahepatic leukocytes, but there is no research to summarize the changes in the liver microenvironment driven by different pathological factors, especially HBV. Therefore, this study attempted to explore the inherent laws of disease-driven microenvironment changes in diseased livers. Using mass cytometry, flow cytometry, and immunofluorescence, we analyzed the changes in intrahepatic leukocytes from mouse liver diseases and patients with hepatocellular carcinoma (HCC) in this study. We noticed that (i) the inhibitory effect of hepatitis B virus (HBV) on intrahepatic leukocytes did not increase with the surface antigen titers compared with the low hepatitis B surface antigen concentration group, intrahepatic T cells from the high one showed higher expression of PD-1 and lower expression of TIM-3 and CTLA-4, so the proportion of exhausted T cells decreased in the high one, which contributed to the tolerance or adaptation of the liver to HBV; (ii) leukocytes in HBV-associated HCC were in a highly dysfunctional state with highest PD-1/TIM-3/CTLA-4/TOX; (iii) the detailed leukocyte ratio was appropriate to assess the prognosis of HCC, the ratio of cytotoxic/naive/effector/central memory CD8+ T cells to CD8+ T cells was positively correlated with the overall survival. In conclusion, our phenotype analysis deeply revealed the function differences in intrahepatic leukocytes caused by different liver disease factors, highlighting their unique changes in HBV related HCC, and helping to discover new HCC targeted immunotherapy strategies. IMPORTANCE Hepatitis B virus (HBV)-specific CD8+ T cells play a central role in the clearance of virus and HBV-related liver injury. Acute infection with HBV induces a vigorous, multifunctional CD8+ T cell response, whereas chronic one exhibits a weaker response. Our study elucidated HBV-specific T cell responses in terms of viral abundance rather than the timing of infection. We showed that in the premalignant stage, the degree of impaired T cell function was not synchronized with the viral surface antigen, which was attributed the liver’s tolerance to the virus. However, after the development of hepatocellular carcinoma, T cell exhaustion was inevitable, and it was marked by the exhaustion of the signature transcription factor TOX.

Keywords

• mass cytometry
• HBV
• intrahepatic leukocytes
• detailed leukocyte ratio