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 1

aPD-L1–IFN-α preferentially targets DCs and macrophages.

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aPD-L1–IFN-α preferentially targets DCs and macrophages. (A and B) Ingui...
(A and B) Inguinal LNs of naive or HBV carrier mice (n = 5/group) were collected. PD-L1 levels on mDCs (A) and CD169–F4/80+ MΦ (B) were assessed by flow cytometry. A representative graph is shown on the left, and the MFI is shown on the right. (C) The single cells from inguinal LNs of HBV carrier mice (n = 5/group) were collected, and the expression of PD-L1 was analyzed by flow cytometry. PD-L1 expression levels on CD4+ T cells (CD3+CD4+), CD8+ T cells (CD3+CD8+), B cells (B220+), macrophages (CD169+F4/80–, CD169–F4/80+, CD169+F4/80+), rDCs (CD11chiMHCII+), and mDCs (CD11c+MHCIIhi) are shown. (D) Schematic representation of the aPD-L1–IFN-α heterodimeric fusion protein adjuvant with LALA-PG mutants in the fragment crystallizable (Fc) domain. (E and F) The single cells from inguinal LNs of HBV carrier mice (n = 4) (E) or Pdl1–/– HBV carrier mice (n = 4) (F) 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. Data are shown as the mean ± SEM and are representative of at least 2 independent experiments. An unpaired 2-tailed Student’s t test was applied in A and B. One-way ANOVA followed by Tukey’s test was applied in C. ****P < 0.0001. Conc., concentrations; MΦ, macrophage; MFI, mean fluorescence intensity.