PD-1 blockade partially recovers dysfunctional virus–specific B cells in chronic hepatitis B infection
Loghman Salimzadeh, … , Patrick T.F. Kennedy, Antonio Bertoletti
Loghman Salimzadeh, … , Patrick T.F. Kennedy, Antonio Bertoletti
Published October 1, 2018; First published August 7, 2018
Citation Information: J Clin Invest. 2018;128(10):4573-4587. https://doi.org/10.1172/JCI121957.
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Research Article Hepatology Infectious disease

PD-1 blockade partially recovers dysfunctional virus–specific B cells in chronic hepatitis B infection

Abstract

Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual-staining method that utilizes hepatitis B virus (HBV) surface antigens (HBsAg) labeled with fluorochromes as “baits” for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function, and phenotype. We studied healthy vaccinated subjects (n = 18) and patients with resolved (n = 21), acute (n = 11), or chronic (n = 96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells were independent of HBV infection status. In contrast, the presence of serum HBsAg affected function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into Ab-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21lo) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells, but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of the cytokines IL-2 and IL-21 and CD40L-expressing feeder cells and was further boosted by the addition of anti–PD-1 Abs. In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell–maturing cytokines and PD-1 blockade.

Authors

Loghman Salimzadeh, Nina Le Bert, Charles-A. Dutertre, Upkar S. Gill, Evan W. Newell, Christian Frey, Magdeleine Hung, Nikolai Novikov, Simon Fletcher, Patrick T.F. Kennedy, Antonio Bertoletti

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Figure 1

Fluorescently labeled HBsAg baits bind specifically to HBsAg-specific B cells.

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Fluorescently labeled HBsAg baits bind specifically to HBsAg-specific B ...
(A) Schematic representation of fluorescently labeled HBsAg baits binding to the BCR on the surface of HBsAg-specific B cells. A healthy subject received an HBV booster vaccination. Serum and blood samples were analyzed from day 0 to day 60 after vaccination. (B) Anti-HBs titers in the serum from day 0 to day 60 after vaccination. (C) Frequency of total plasmablasts (CD19+CD10–CD21–/loCD27++CD38++) out of total B cells measured longitudinally. (D) Flow cytometry plots show the frequency of HBsAg double-binding MBCs (top panel) and their percentages displaying a plasmablast phenotype (bottom panel). The first plot at the left shows data of a healthy unvaccinated subject. The other plots show data of a healthy vaccinated subject at the indicated time points before and after the HBV booster vaccination. (E) Frequency of HBsAg double-binding MBCs over time. (F) MFI of HBsAg-D550 and HBsAg-D650 on HBsAg-specific B cells at different time points. (G) Equal numbers of HBsAg-D550+D650+ and HBsAg-D550–D650– MBCs were FACS sorted from PBMCs of day 60 after booster vaccination and triggered for Ab production by CpG and sCD40L polyclonal activation. Cells were cultured in 2 different steps with different cytokine mixtures. Subsequently, anti-HBs ELISA and anti-HBs ELISpot assays were performed on culture supernatants and on the cells, respectively.