A novel T-cell epitope in the transmembrane region of the hepatitis B virus envelope protein responds upon dendritic cell expansion

Hepatitis B virus: promising drug targets and therapeutic implications

Introduction: Current therapy for infection with hepatitis B virus (HBV) rarely clears the virus, and viremia commonly resurges following treatment withdrawal. To prevent serious complications of the infection, research has been aimed at identifying new viral and host targets that can be exploited to inactivate HBV replication.Areas covered: This paper reviews the use of these new molecular targets to advance anti-HBV therapy. Emphasis is on appraising data from pre-clinical and early clinical studies described in journal articles published during the past 10 years and available from PubMed.Expert opinion: The wide range of viral and host factors that can be targeted to disable HBV is impressive and improved insight into HBV molecular biology continues to provide the basis for new drug design. In addition to candidate therapies that have direct or indirect actions on HBV covalently closed circular DNA (cccDNA), compounds that inhibit HBsAg secretion, viral entry, destabilize viral RNA and effect enhanced immune responses to HBV show promise. Preclinical and clinical evaluation of drug candidates, as well as investigating use of treatment combinations, are encouraging. The field is poised at an interesting stage and indications are that reliably achieving functional cure from HBV infection is a tangible goal.

Transforming growth factor β as a possible independent factor in chronic hepatitis B

To investigate the association between immune-cell-related cytokines and the development of chronic hepatitis B (CHB), patients with chronic hepatitis B virus (HBV) infection in the immunotolerant (IT) phase (n = 30) or hepatitis B envelope antigen (HBeAg)-positive CHB (n = 250) were enrolled in this study. Serological indicators and plasma cytokine levels were measured at the time of enrollment. The results showed that there were significant differences in the median age of the patients (27 vs. 31 years), alanine aminotransferase levels (ALT, 29.85 vs. 234.70 U/L), alanine aminotransferase levels (AST, 23.40 vs. 114.90 U/L), HBsAg levels (4.79 vs. 3.88 log₁₀ IU/ml), HBeAg levels (1606.36 vs. 862.47 S/CO), and the HBV DNA load (8.17 vs. 6.71 log₁₀ IU/ml) between the IT and CHB groups (all P < 0.01). The median values of Fms-like tyrosine kinase 3 ligand (FLT3-L), interferon-gamma (IFN-γ), interleukin- 17A (IL-17A), and transforming growth factor beta (TGF-β1) were significantly higher in the IT group than in the CHB group (FLT3-L, 41.62 vs. 27.47 pg/ml; IFN-γ, 42.48 vs. 33.18 pg/ml; IL-17A, 15.66 vs. 8.90 pg/ml; TGF-β1, 4921.50 vs. 2234 pg/ml; all P < 0.01). The median IFN-α2, TGF-β3 and IL-10 levels in the IT group were significantly lower than those in the CHB group (IFN-α2, 15.24 vs. 35.78 pg/ml, P = 0.000; TGF-β3, 131.69 vs. 162.61 pg/ml, P = 0.025; IL-10, 5.02 vs. 7.9 pg/ml, P = 0.012). Multivariate logistic regression analysis indicated that TGF-β 1 (OR = 0.999, 95% CI 0.999-1.000, P < 0.001) and TGF-β2 levels (OR = 1.008, 95%CI 1.004-1.012, P < 0.001) were modestly but significantly associated with the incidence of CHB. The results suggest that TGF-β level might be an independent factor related to the occurrence of CHB.

In Silico Prediction of Human Leukocytes Antigen (HLA) Class II Binding Hepatitis B Virus (HBV) Peptides in Botswana

Hepatitis B virus (HBV) is the primary cause of liver-related malignancies worldwide, and there is no effective cure for chronic HBV infection (CHB) currently. Strong immunological responses induced by T cells are associated with HBV clearance during acute infection; however, the repertoire of epitopes (epi) presented by major histocompatibility complexes (MHCs) to elicit these responses in various African populations is not well understood. In silico approaches were used to map and investigate 15-mers HBV peptides restricted to 9 HLA class II alleles with high population coverage in Botswana. Sequences from 44 HBV genotype A and 48 genotype D surface genes (PreS/S) from Botswana were used. Of the 1819 epi bindings predicted, 20.2% were strong binders (SB), and none of the putative epi bind to all the 9 alleles suggesting that multi-epitope, genotype-based, population-based vaccines will be more effective against HBV infections as opposed to previously proposed broad potency epitope-vaccines which were assumed to work for all alleles. In total, there were 297 unique epi predicted from the 3 proteins and amongst, S regions had the highest number of epi (n = 186). Epitope-densities (D_epi) between genotypes A and D were similar. A number of mutations that hindered HLA-peptide binding were observed. We also identified antigenic and genotype-specific peptides with characteristics that are well suited for the development of sensitive diagnostic kits. This study identified candidate peptides that can be used for developing multi-epitope vaccines and highly sensitive diagnostic kits against HBV infection in an African population. Our results suggest that viral variability may hinder HBV peptide-MHC binding, required to initiate a cascade of immunological responses against infection.