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 5

aPD-L1–IFN-α overcomes immune tolerance by aPD-L1-mediated cis-targeting.

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aPD-L1–IFN-α overcomes immune tolerance by aPD-L1-mediated cis-targeting...
(A–D) HBV carrier mice or Pdl1–/– HBV carrier mice (n = 5/group) were injected s.c. with a single dose of aPD-L1–IFN-α (2 μg/mouse) or PBS. After 24 hours, the expression of CD80 on DCs and macrophages in inguinal dLNs was analyzed by flow cytometry. The expression of CD80 on CD103+ mDCs (A), CD11b+ mDCs (B), CD169+F4/80+ MΦ (C), and CD169–F4/80+ MΦ (D) is shown. (E and F) Inguinal LNs of DC Pdl1–/– HBV carrier mice (n = 6) were collected and analyzed by flow cytometry. PD-L1 expression levels on CD4+ T cells, CD8+ T cells, B cells, macrophages, rDCs, and mDCs are shown (E). Single cells from inguinal LNs of DC Pdl1–/– HBV carrier mice (n = 3) were collected and incubated with aPD-L1–IFN-α (human IgG1 Fc) at the indicated concentrations, followed by incubation with fluorescently labeled antibodies and anti–human IgG Fc (PE-Cy7 label) in vitro. The MFI of PE-Cy7 was detected by flow cytometry (F). (G–J) HBV carrier mice or DC Pdl1–/– HBV carrier mice (n = 5/group) were injected s.c. with a single dose of aPD-L1–IFN-α (2 μg/mouse) or PBS. After 24 hours, the expression of CD80 on DCs and macrophages in inguinal dLNs was analyzed by flow cytometry. The expression of CD80 on CD103+ mDCs (G), CD11b+ mDCs (H), CD169+F4/80+ MΦ (I) and CD169–F4/80+ MΦ (J) is shown. (K and L) HBV carrier mice or DC Pdl1–/– HBV carrier mice (n = 3/group) were treated as described in Figure 3A. Serum levels of ayw subtype–specific anti-HBsAg IgG (K) and HBsAg (L) were determined by ELISA. The detection limit in L is indicated by a dashed line. Data are shown as the mean ± SEM (A–J) or mean + SEM (K and L) and are representative of at least 2 independent experiments. One-way ANOVA followed by Tukey’s test was applied in A–E and G–J) **P < 0.01; ***P < 0.001; ****P < 0.0001. Conc., concentrations; MΦ, macrophage; MFI, mean fluorescence intensity; OD, optical density.