JAK/STAT signaling is involved in IL-35-induced inhibition of hepatitis B virus antigen-specific cytotoxic T cell exhaustion in chronic hepatitis B

Abstract

AimsInterleukin-35 (IL-35) is a new member of the interleukin-12 family and is composed of the P35 and EB virus-inducible gene 3 subunits. The aims of this study were to examine the roles of IL-35 in the exhaustion of HBV-specific CTLs, as little as known on the subject. Main methodsThe relative levels of serum HBV markers were detected using automated biochemical techniques. The HBV DNA copies were measured by RT-qPCR. The expression of inhibitory receptors and the cell cytokines on the surface of CTLs were determined by flow cytometry. The pSTAT1-pSTAT4 protein levels expression was determined by flow cytometry, confocal microscopy and Western blot. Key findingsOur results showed that IL-35 can activate the Janus kinase 1 (JAK1)/tyrosine kinase 2 (TYK2)/signal transducer and activator of transcription 1 (STAT1)/STAT4 pathway in CTLs in vitro. Interferon-γ and tumor necrosis alpha-α expression increased in CTLs in the presence of a JAK/STAT-pathway blocker. In addition, we evaluated the expression of the exhaustion-associated molecules programmed death-1, cytotoxic T lymphocyte-associated protein-4, and lymphocyte activation gene-3 in CTLs after adding the JAK-STAT inhibitor The results showed that the expression of exhaustion-associated molecules on the CTL surface decreased after blocking the JAK-STAT pathway. IL-35 inhibited the function of HBV-specific CTLs through the JAK1/TYK2/STAT1/STAT4 pathway, and the function of CTLs was recovered after blocking the JAK/STAT pathway. SignificanceThese data provide a new experimental basis for immunotherapy for chronic hepatitis B.