Dear Editor,
We are immensely grateful to Professor Zuzana Macek Jilkova and Professor Caroline Aspord for their insightful commentary that encapsulates the key findings of our publication in the same issue [
1,
2]. We are also appreciative of the opportunity to engage with their valuable insights and perspectives.
A growing body of evidence indicates that the inability to attain a functional cure for hepatitis B virus (HBV) signifies not only the exhaustion of virus-specific T cell responses but also the dysregulation of innate immunity, particularly involving natural killer (NK) cells [
3,
4]. As stated in the editorial, the T-cell receptor-like antibody specific for the HBV core 18-27 epitope (cTCRL-Ab) was initially developed by Antonio Bertoletti’s group for the purpose of visualizing peptide major histocompatibility complex (MHC) complexes and selectively delivering interferon-α (IFNα) to HBV-infected hepatocytes. Inspired by the HBV-specific targeting and Fc structure of cTCRL-Ab, we investigated whether it could enhance the antibody-dependent cellular cytotoxicity (ADCC) function of intrahepatic NK cells, thereby exerting antiviral effects. However, we found that the expression level of peptide-MHC complexes on HBV-infected hepatocytes was inadequate to effectively activate NK cells, thereby limiting its translational clinical potential. Consequently, we repurposed cTCRL-Ab as a tool to evaluate NK cell ADCC activity. We are appreciative of the editorial’s accurate recognition of the conceptual advancement enabled by this antibody, specifically its utility in probing antigen-specific, Fc-dependent NK cell function. We are grateful for the authors’ thoughtful synthesis of our findings and their clear articulation of how our work addresses a key gap in understanding NK cell biology in HBV.
A salient insight accentuated by the editorial is the substantiation and elaboration of the functional dichotomy of NK cells in chronic HBV. Our research indicates that, while degranulation capacity remains, IFN-γ production from NK cells in response to cTCRL-Ab engagement is significantly impaired. This finding is consistent with the established concept of impaired NK cell function in chronic viral infections [
5,
6]. As a fundamental component of immune-based therapeutic interventions for HBV, the effects of pegylated interferon-α (Peg-IFNα) on NK cells are increasingly recognized as multifaceted and context-dependent.7 Notably, our study also demonstrates that cTCRL-Ab-mediated NK cell responses were significantly impaired in patients with chronic hepatitis B (CHB) undergoing Peg-IFNα therapy. This effect has been associated with interferon-induced downregulation of CD16 expression. These findings are not consistent with the established role of IFNα in activating NK cells as traditionally understood. However, the editorial adroitly resolves this apparent paradox by emphasizing that IFNα acts as a precise reprogramming agent. The commentary judiciously reframes Peg-IFNα-induced CD16 downregulation not as a uniform suppression of NK activity, but rather as a selective remodeling of the CD16
hi NK cell compartment. This compelling interpretation underscores the importance of examining immune responses in functionally distinct subsets.
The conventional NK cell categorization has been demonstrated to be inadequate. Single-cell studies have revealed significant heterogeneity within the NK cell compartment during HBV infection [
8]. In accordance with this emerging concept, our single-cell RNA sequencing analysis revealed functionally distinct subsets within the CD16
hi NK population. Intriguingly, our research identified a cytotoxic CX3CR1
+KLRC2
-CD16
hi NK subset that was enriched in patients with favorable treatment responses and in individuals achieving hepatitis B surface antigen loss [
1]. This finding aligns with the core point that the editorial commends. The positioning of immune cells, guided by chemokines, has emerged as a critical determinant of antiviral immunity. The CX3CL1/CX3CR1 axis plays a crucial role in HBV clearance by recruiting cytotoxic immune cells to sites of HBV infection, thereby participating in and regulating the host’s antiviral immune response [
9,
10]. The identification of the CX3CR1
+KLRC2
-CD16
hi NK cell subset as a correlate of favorable treatment outcomes is thoughtfully contextualized in the editorial, particularly with regard to the CX3CL1/CX3CR1 axis and its potential role in immune cell trafficking and intercellular crosstalk within the hepatic microenvironment. We appreciate the authors’ perspective that it may reflect a specialized cytotoxic population relevant to antiviral immunity in HBV, which will contribute to refining the understanding of NK cell biology. We also thank the authors for recognizing the importance of extending our analyses beyond peripheral blood to intrahepatic NK cells. It is acknowledged that additional longitudinal and spatially resolved studies of intrahepatic immune cells are imperative to comprehensively elucidate the dynamics of NK cell regulation during therapy.
A mounting body of evidence has underscored the significance of the interregulation of cellular metabolism and the immune response. Indeed, the report by Xun and colleagues demonstrates that taurocholic acid can impede the response to Peg-IFNα therapy by compromising the functionality of NK cells in patients with hepatitis B e antigen positive CHB [
11]. This finding underscores the significance of metabolic factors in modulating Peg-IFNα responsiveness during CHB treatment. This also demonstrates the commentary’s profound insights into investigating cTCRL-Ab’s effects on NK cell function from the perspective of metabolic reprogramming. Finally, we concur with the editorial’s assertion that our findings have implications for the development and evaluation of next-generation HBV therapies. A comprehensive understanding of immune competence in chronic HBV can be achieved by incorporating considerations of antibody-mediated NK cell functions, natural cytotoxicity, and adaptive immune responses. Furthermore, tools such as cTCRL-Ab may have future utility not only for mechanistic studies, but also for monitoring immune restoration or for the preclinical assessment of Fc-engineered antibodies designed to enhance NK cell-mediated antiviral activity.
In conclusion, we are appreciative of this constructive and forward-looking commentary, which we believe enhances the interpretation of our work and situates it within the broader endeavor to achieve immune-based functional cures for HBV. It is our hope that the ongoing investigation into the heterogeneity of NK cells and the antibody-dependent effector mechanisms will contribute to the rational design of more effective therapeutic strategies.
FOOTNOTES
-
Authors’ contribution
LBT, YHW, ZHJ, SHZ, YYL are responsible for manuscript preparation, concept synthesis and finalization. All authors read and approved the final manuscript.
-
Acknowledgements
This work was supported by grants from the National Natural Science Foundation of China (82270647 and 82272314).
-
Conflicts of Interest
The authors have no conflicts to disclose.
Abbreviations
antibody-dependent cellular cytotoxicity
T-cell receptor-like antibody specific for HBV core 18-27 epitope
major histocompatibility complex
REFERENCES
- 1. Tang L, Wang Y, Jin Z, Gu Y, Zeng Z, Song L, et al. Dissecting antibody-mediated natural killer cell effects reveals a cytotoxic CX3CR1+KLRC2-CD16hi subset linked to hepatitis B virus outcomes. Clin Mol Hepatol 2026;32:683-705.
- 2. Macek Jilkova Z, Aspord C. New insights into antibody-mediated NK cell immunity in hepatitis B: Editorial on “Dissecting antibody-mediated NK cell effects reveals a cytotoxic CX3CR1⁺KLRC2⁻CD16hi subset linked to HBV outcomes”. Clin Mol Hepatol 2026;32:1448-1451.
- 3. Hui RW, Mak LY, Fung J, Seto WK, Yuen MF. Prospect of emerging treatments for hepatitis B virus functional cure. Clin Mol Hepatol 2025;31:S165-S181.
- 4. Ho KC, Hui RW, Seto WK, Yuen MF, Mak LY. Targeting the innate immune system in treating hepatitis B: prospects for functional cure. Clin Mol Hepatol 2026;32:184-199.
- 5. Björkström NK, Strunz B, Ljunggren HG. Natural killer cells in antiviral immunity. Nat Rev Immunol 2022;22:112-123.
- 6. Yu Y, Wang Z, Yang A, Wang Y, Bao C, Zhuoa L, et al. Chronic HBV infection impairs the glucose metabolism and effector function of NK cells via HBsAg/IL-15/mTOR axis. Cell Death Dis 2025;16:721.
- 7. Gill US, Peppa D, Micco L, Singh HD, Carey I, Foster GR, et al. Interferon alpha induces sustained changes in NK cell responsiveness to hepatitis B viral load suppression in vivo. PLoS Pathog 2016;12:e1005788.
- 8. Zhang C, Li J, Cheng Y, Meng F, Song JW, Fan X, et al. Single-cell RNA sequencing reveals intrahepatic and peripheral immune characteristics related to disease phases in HBV-infected patients. Gut 2023;72:153-167.
- 9. Jiang P, Jia H, Qian X, Tang T, Han Y, Zhang Z, et al. Single-cell RNA sequencing reveals the immunoregulatory roles of PegIFNa in patients with chronic hepatitis B. Hepatology 2024;79:167-182.
- 10. Kondo Y, Kimura O, Tanaka Y, Ninomiya M, Iwata T, Kogure T, et al. Differential expression of CX3CL1 in hepatitis B virus-replicating hepatoma cells can affect the migration activity of CX3CR1+ immune cells. J Virol 2015;89:7016-7027.
- 11. Xun Z, Lin J, Yu Q, Liu C, Huang J, Shang H, et al. Taurocholic acid inhibits the response to interferon-a therapy in patients with HBeAg-positive chronic hepatitis B by impairing CD8+ T and NK cell function. Cell Mol Immunol 2021;18:461-471.
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