Interleukin-35 modulates the balance between viral specific CD4+CD25+CD127dim/- regulatory T cells and T helper 17 cells in chronic hepatitis B virus infection

Abstract

Background Interleukin (IL)-35 regulates imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, leading to an important modulator in autoimmune disorder, cancer, and infectious diseases. Our previous study revealed an immunosuppressive activity of IL-35 in chronic hepatitis B virus (HBV) infection. Thus, the aim of the current study was to investigate the role of regulatory function of IL-35 to viral specific Tregs/Th17 cells balance in chronic HBV infection. Methods A total of 44 HLA-A2 restricted chronic HBV infected patients, including 21 of chronic hepatitis B (CHB) and 23 of asymptomatic HBV carriers (ASC) were enrolled. Purified CD4 + T cells or CD4 + CD25 + CD127 dim/− Tregs were stimulated with recombinant IL-35. HBV core antigen specific Tregs and Th17 cells were determined by flow cytometry. FoxP3 and RORγt mRNA was measured by real-time PCR. Cytokines production (IL-10 and IL-17) was investigated by ELISA. Results Peripheral viral specific Tregs was comparable between CHB and ASC. However, increased percentage of viral specific Th17 cells was found in CHB, leading to the reduction of Tregs/Th17 ratio in CHB patients. IL-35 stimulation elevated viral specific Tregs, but not Th17 cells frequency, in both CHB and ASC, resulting in the elevation of Tregs/Th17 ratio in both groups. This process was accompanied by increased expression of FoxP3 mRNA and IL-10 production, and decreased IL-17 secretion and STAT3 phosphorylation in purified CD4 + T cells. Moreover, IL-35 stimulation inhibited viral specific Th17-like phenotype differentiation from Tregs in CHB patients. Effective anti-HBV therapy did not affect viral specific Tregs/Th17 cells frequency or IL-35 expression in CHB patients, however, reduced responsiveness of CD4 + T cells or Tregs to IL-35 stimulation in vitro. Conclusion Our findings indicated that IL-35 regulation to viral specific Tregs/Th17 balance may contribute to viral persistence in chronic HBV infection.

The Role of IL-35 in the Pathophysiological Processes of Liver Disease

“…At the same time, studies found that Tregs and other cell types (including activated myeloid, endothelial cells, regulatory B cells) was capable to secret IL-35 ( Yang et al, 2020a ). Evidence showed that HBV could initiate CD4+ CD25+ Tregs to express IL-35 ( Schneider et al, 2018 ; Yang et al, 2019a ). The expression levels of EBI3, p35 and receptor of IL-35 were also highly expressed in CD4+ CD25+ Tregs of CHB patients.…”

“…The expression levels of EBI3, p35 and receptor of IL-35 were also highly expressed in CD4+ CD25+ Tregs of CHB patients. Notably, their expression levels were proved to be equal in activated and inactivated CD4+ CD25+ Tregs, which suggested that IL-35 could be secreted in activated and inactivated CD4+ CD25+ Tregs ( Yang et al, 2019a ). Additionally, the regulatory function of Tregs in EBI3−/− or p35 −/− mice was significantly inhibited compared to that of control group, implicating that IL-35 was vital for the activity of Treg’ functions.…”

“…HBV core antigen induced-CD45RA expression level was significantly decreased by IL-35 in total CD4+ T cells, showing that IL-35 has protective role in CD4+ T mediate adaptive immune in HBV attack. Additionally, the effect of IL-35 on innate immune response marked by CD11c (a DC marker) and CD86 (an activation marker of DC) were investigated ( Yang et al, 2019a ; Teng et al, 2019 ). IL-35 significantly decreased the proportion of CD11c+ cells in PBMCs, but the proportion of CD86 on CD11c+ cells increased slightly ( Dong et al, 2020 ).…”

“…Besides, IL-35 was recognized as an indispensable molecule in suppressing Th1/Th17 cells and weakening immune response to pathogen. IL-35 could partly attenuate chronic liver inflammation by inhibiting IL-17 production and Th17 differentiation from CD4+ T cells in vitro , and reducing the amount of Th17 cells of liver in vivo ( Zheng et al, 2018 ; Yang et al, 2019a ). Ye et al found that IL-17-prodocing cells increased in liver fibrosis ( Teng et al, 2019 ).…”

Intrahepatic TH17/TReg Cells in Homeostasis and Disease—It’s All About the Balance

“…An imbalance in T H 17/T Reg cells was thereby an independent predictive factor for decompensated liver cirrhosis ( Lan et al, 2019 ). In addition, Yang et al demonstrated that IL-35 is responsible to balance the T Reg and T H 17 balance in acute and chronic HBV infection by preferentially increasing virus-specific T Reg cells and the prevention of T H 17 cell differentiation ( Yang et al, 2019 ). In conclusion, T Reg and T H 17 cells contribute to the immune response during viral liver infection and the optimal balance is important for an effective antiviral immune response and prevention of complications ( Figure 4 ).…”