Effects of Hepatitis B Surface Antigen on Virus-Specific and Global T Cells in Patients With Chronic Hepatitis B Virus infection.

BACKGROUND & AIMS: Chronic hepatitis B virus (HBV) infection is characterized by the presence of defective viral envelope proteins (hepatitis B surface antigen [HBsAg]) and the duration of infection-most patients acquire the infection at birth or during the first years of life. We investigated the effects of these factors on patients' lymphocyte and HBV-specific T-cell populations. METHODS: We collected blood samples and clinical data from 243 patients with HBV infection (3-75 years old) in the United Kingdom and China. We measured levels of HBV DNA, HBsAg, hepatitis B e antigen, and alanine aminotransferase; analyzed HBV genotypes; and isolated peripheral blood mononuclear cells (PBMCs). In PBMCs from 48 patients with varying levels of serum HBsAg, we measured 40 markers on nature killer and T cells by mass cytometry. PBMCs from 189 patients with chronic infection and 38 patients with resolved infections were incubated with HBV peptide libraries, and HBV-specific T cells were identified by interferon gamma enzyme-linked immune absorbent spot (ELISpot) assays or flow cytometry. We used multivariate linear regression and performed variable selection using the Akaike information criterion to identify covariates associated with HBV-specific responses of T cells. RESULTS: Although T- and natural killer cell phenotypes and functions did not change with level of serum HBsAg, numbers of HBs-specific T cells correlated with serum levels of HBsAg (r = 0.3367; P < .00001). After we performed the variable selection, the multivariate linear regression model identified patient age as the only factor significantly associated with numbers of HBs-specific T cells (P = .000115). In patients younger than 30 years, HBs-specific T cells constituted 28.26% of the total HBV-specific T cells; this value decreased to 7.14% in patients older than 30 years. CONCLUSIONS: In an analysis of immune cells from patients with chronic HBV infection, we found that the duration of HBsAg exposure, rather than the quantity of HBsAg, was associated with the level of anti-HBV immune response. Although the presence of HBs-specific T cells might not be required for the clearance of HBV infection in all patients, strategies to restore anti-HBV immune responses should be considered in patients younger than 30 years.

CD163+ cytokine-producing cDC2 stimulate intratumoral type 1 T cell responses in HPV16-induced oropharyngeal cancer.

BACKGROUND: Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is a distinct clinical entity with a much better prognosis after (chemo)radiotherapy than HPV-negative OPSCC, especially in patients with a concomitant intratumoral HPV-specific and type-1 cytokine-oriented T cell response. However, knowledge on the type of myeloid cells and their coordination with intratumoral T cells and influence on patient outcome in OPSCC is lacking. METHODS: We analyzed the presence of intratumoral myeloid cells and their relationship to tumor-infiltrating T cells and patient outcome in a well-described cohort of HPV16+ patients with OPSCC using multispectral immunofluorescence, flow cytometry and functional analyses. RESULTS: We show that the tumor microenvironment of HPV16+ OPSCC tumors with such an ongoing HPV16-specific T cell response is highly infiltrated with a newly defined CD163+ cytokine-producing subset of conventional dendritic cell type 2 (cDC2), called DC3. These CD163+ cDC2 predominantly stimulated type 1 T cell polarization and produced high levels of interleukin-12 (IL-12) and IL-18, required for IFNγ and IL-22 production by T cells after cognate antigen stimulation. Tumor-infiltration with these CD163+ cDC2 positively correlated with the infiltration by Tbet+ and tumor-specific T cells, and with prolonged survival. CONCLUSIONS: These data suggest an important role for intratumoral CD163+ cDC2 in stimulating tumor-infiltrating T cells to exert their antitumor effects.

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

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.