Restoration of CD3+CD56+ NKT-like cell function by TIGIT blockade in inactive carrier and immune tolerant patients of chronic hepatitis B virus infection.

Chronic hepatitis B (CHB) virus infection, which can be divided into immune-tolerant (IT), immune-active (IA), inactive carrier (IC) phases, and HBeAg-negative hepatitis (ENEG), can induce liver cirrhosis and eventually hepatocellular carcinoma (HCC). CD3+CD56+ NKT-like cells play an important role in antiviral immune response. However, the mechanism of NKT-like cells to mediate immune tolerance remains largely elusive. In this study, we observed circulating NKT-like cells from IC and IT CHB patients were phenotypically and functionally impaired, manifested by increased expression of inhibitory receptor TIGIT and decreased capacity of secreting antiviral cytokines. Besides, TIGIT+ NKT-like cells of IC and IT CHB patients expressed lower levels of cytotoxic cytokines than the TIGIT- subset. Furthermore, increased expression of CD155, the ligand of TIGIT, on plasmacytoid dendritic cells (pDCs) was detected in IC and IT CHB patients. Importantly, the co-culture of NKT-like cells and pDCs showed that NKT-like cells restored their antiviral ability after TIGIT blockade upon HBV peptide stimulation in IC and IT CHB patients. In conclusion, our findings suggest that the TIGIT pathway may mediate immune tolerance in IT CHB patients and lead to functional impairment in IC patients, indicating that TIGIT may be a potential therapeutic checkpoint for immunotherapy of CHB patients.

A single-cell atlas of the peripheral immune response in patients with influenza A virus infection.

Influenza A virus (IAV) remains a pressing global health concern, yet our understanding of the specific nature and functional roles of certain circulating cell subsets in relation to this viral infection remains unclear. We performed single-cell RNA sequencing (scRNA-seq) on single-cell whole-blood (scWB) isolated from various populations using the Singleron Matrix platform. Our investigation showed a significant upregulation of the IFN-stimulated gene, IFN-α-inducible protein 27 (IFI27), in patients affected by IAV infection and further found that the heightened expression of IFI27 was primarily concentrated in specific immune cell populations, including monocytes and conventional dendritic cells (cDCs). Notably, we identified a specific subset of neutrophils, neutrophil_ISG15, which implicates interferon (IFN) signaling in IAV infection. Our findings provide a comprehensive understanding of the cellular subtypes and molecular characteristics of scWB across different populations with IAV infection.