Anti–PD-L1–IFN-α–adjuvanted HBsAg vaccine overcomes HBV immune tolerance through targeting both DCs and macrophages
Chao-Yang Meng, Yong Liang, Longxin Xu, Hongjia Li, Jingya Guo, Hairong Xu, Fan Wang, Yang-Xin Fu, Hua Peng
Chao-Yang Meng, Yong Liang, Longxin Xu, Hongjia Li, Jingya Guo, Hairong Xu, Fan Wang, Yang-Xin Fu, Hua Peng
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Research Article Hepatology Immunology Virology

Anti–PD-L1–IFN-α–adjuvanted HBsAg vaccine overcomes HBV immune tolerance through targeting both DCs and macrophages

Abstract

Recombinant hepatitis B surface antigen (rHBsAg) vaccine with various adjuvants fails to break T and B cell tolerance in hosts with chronic hepatitis B (CHB). This study aims to explore the mechanisms to break immune tolerance that allows the host to respond to rHBsAg, achieving a cure for CHB. We engineered an anti–PD-L1–IFN-α (aPD-L1–IFN-α) heterodimeric fusion protein to allow rHBsAg to rejuvenate T and B cell responses in hepatitis B virus–tolerant (HBV-tolerant) mice. S.c. coimmunization with aPD-L1–IFN-α and rHBsAg significantly enhanced antigen uptake and maturation of both macrophage and dendritic cell (DC) subsets in draining lymph nodes. Macrophages drove early B cell activation, while cDC1s primed CD8+ T cells, breaking tolerance and leading to both B cell and cytotoxic T lymphocyte (CTL) differentiation. This strategy elicited not only anti-HBsAg neutralizing antibodies but also HBsAg-specific CD8+ T cell responses, achieving a functional cure without systemic toxicity. The efficacy of the aPD-L1–IFN-α adjuvant depended on both PD-L1 cis-targeting and IFN-α receptor signaling in antigen-presenting cells. These findings establish aPD-L1–IFN-α as a translatable adjuvant to break the strong tolerance induced by CHB, providing a dual-pathway strategy to induce HBV-specific T and B cell responses.

Authors

Chao-Yang Meng, Yong Liang, Longxin Xu, Hongjia Li, Jingya Guo, Hairong Xu, Fan Wang, Yang-Xin Fu, Hua Peng

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Figure 2

aPD-L1–IFN-α enhances the antigen uptake and maturation of APCs in dLNs.

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aPD-L1–IFN-α enhances the antigen uptake and maturation of APCs in dLNs....
(A–E) Schematic diagram of s.c. injection of HBsAg-FITC (1 μg/mouse) mix or without aPD-L1–IFN-α (2 μg/mouse) into HBV carrier mice. Six hours after injection, the uptake of HBsAg-FITC by DCs and macrophages in inguinal dLNs was analyzed using flow cytometry (A). The uptake of HBsAg-FTIC by CD103+ mDCs (B), CD11b+ mDCs (C), CD169+F4/80+ MΦ (D), and CD169–F4/80+ MΦ (E) is shown (n = 5/group). (F–J) Schematic diagram of a single-dose s.c. injection of IFN-α–Fc (0.78 μg/mouse) or aPD-L1–IFN-α (2 μg/mouse) (determined by equimolar of IFN-α subunit) into HBV carrier mice. After 24 hours, the expression of costimulatory molecules on DCs and macrophages in inguinal dLNs was analyzed by flow cytometry (F). The expression of CD86 on CD103+ mDCs (G), CD11b+ mDCs (H), CD169+F4/80+ MΦ (I), and CD169–F4/80+ MΦ (J) is shown (n = 5/group). Data are shown as the mean ± SEM and are representative of at least 2 independent experiments. One-way ANOVA followed by Tukey’s test was applied in B–E and G–J. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. FITC, fluorescein isothiocyanate; MΦ, macrophage; MFI, mean fluorescence intensity.