Anti-HBc: a significant host predictor of spontaneous HBsAg seroclearance in chronic hepatitis B patients - a retrospective longitudinal study

BACKGROUND AND AIM

In chronic hepatitis B infection (CHB), seroclearance of hepatitis B surface antigen (HBsAg) is associated with favourable clinical outcomes compared to those with persistent HBsAg seropositivity, and thus considered as a desired treatment endpoint. This current study explores the possibility of serum antibody to hepatitis B core antigen (anti-HBc) as a potential predictive factor of HBsAg seroclearance.

METHODS

This is a retrospective study that analyzed the plasma samples of CHB patients using the LUMIPULSE® G1200 analyzer. The longitudinal anti-HBc level between patients who subsequently achieved HBsAg seroclearance (S-losers) and those with persistent HBsAg-positivity (controls) were compared at multiple time points before the event.

RESULTS

A total of 240 subjects (120 S-losers and 120 controls; age- and gender-matched) were included (mean age 56.42 ± 10.81, 65% male). Compared to controls, S-losers had significantly lower plasma anti-HBc levels prior to HBsAg seroclearance, with a significant trend of declining plasma anti-HBc 8-5 years prior to HBsAg seroclearance (p < 0.01), while such trend was not observed in controls. ROC curve analysis revealed that plasma anti-HBc at multiple time points before HBsAg seroclearance return AUC greater than 0.7. Plasma anti-HBc level at the cut-off value of 82.50 COI was 68.3% sensitive and 90% specific for HBsAg seroclearance within 1 year. Combining with quantitative HBsAg < 100 IU/mL, anti-HBc < 82.5 COI identified 88.2% patients who would develop HBsAg seroclearance within 1 year.

CONCLUSION

Plasma anti-HBc level began to decline 10 years prior to HBsAg seroclearance and can serve as a potential predictor for subsequent HBsAg seroclearance.

Immune response induced by recombinant pres2/S-protein and a pres2-S-protein fused with a core 18-27 antigen fragment of hepatitis B virus compared to conventional HBV vaccine

Although comprehensive vaccination is the cornerstone of public health programs to control hepatitis B virus (HBV) infections, 5% of people who receive the existing vaccine do not develop proper immunity against HBV. To overcome this challenge, researchers have tried using various protein fragments encoded by the virus genome to achieve better immunization rates. An important antigenic component of HBsAg called the preS2/S or M protein has also received much attention in this area. The gene sequences of preS2/S and Core18-27 peptide were extracted from the GenBank (NCBI). Final gene synthesis was conducted with pET28. Groups of BALB/c mice were immunized with 10 μg/ml of recombinant proteins and 1 μg/ml CPG7909 adjuvant. Serum levels of IF-γ, TNF-α, IL-2, IL-4, and IL-10 were measured by ELISA assay method on spleen cell cultures on day 45, and IgG1, IgG2a, and total IgG titers obtained from mice serum were quantified on days 14 and 45. Statistical analysis did not show any significant difference between the groups regarding IF-γ level. There were, however, significant differences in terms of IL-2 and IL-4 levels between the groups receiving preS2/S-C18-27 with and without adjuvant and the groups receiving both preS2/S and preS2/S-C18-27 (Plus Recomb-Plus Recomb: the group of mice that received both preS2/S and preS2/S-C18-27 simultaneously). The strongest total antibody production was induced by immunization with both recombinant proteins without CPG adjuvant. The groups that received both preS2/S and preS2/S-C18-27, whether with or without adjuvant, were significantly different from those that received the conventional vaccine considering most abundant interleukins. This difference suggested that higher levels of efficacy can be achieved by the use of multiple virus antigen fragments rather than using a single fragment.

Hepatitis B virus pre-genomic RNA and hepatitis B core-related antigen reductions at week 4 predict favourable hepatitis B surface antigen response upon long-term nucleos(t)ide analogue in chronic hepatitis B

BACKGROUND/AIMS

We investigated the dynamics of serum HBV pre-genomic RNA (pgRNA) and hepatitis B core-related antigen (HBcrAg) in patients receiving nucleos(t)ide analogues (NAs) and their predictability for favourable suppression of serum hepatitis B surface antigen (HBsAg).

METHODS

Serum viral biomarkers were measured at baseline, weeks 4, 12, 24, 36, and 48 of treatment. Patients were followed up thereafter and serum HBsAg level was measured at end of follow-up (EOFU). Favourable HBsAg response (FHR) was defined as ≤100 IU/mL or HBsAg seroclearance upon EOFU.

RESULTS

Twenty-eight hepatitis B e antigen (HBeAg)-positive and 36 HBeAg-negative patients (median, 38.2 years old; 71.9% male) were recruited with median follow-up duration of 17.1 years (interquartile range, 12.8-18.2). For the entire cohort, 22/64 (34.4%) achieved FHR. For HBeAg-positive patients, serum HBV pgRNA decline at week 4 was significantly greater for patients with FHR compared to non-FHR (5.49 vs. 4.32 log copies/mL, respectively; P=0.016). The area under the receiver-operating-characteristic curve (AUROC) for week 4 HBV pgRNA reduction to predict FHR in HBeAg-positive patients was 0.825 (95% confidence interval [CI], 0.661-0.989). For HBeAg-negative patients, instead of increase in serum HBcrAg in non-FHR patients, FHR patients had median reduction in HBcrAg at week 4 (increment of 1.75 vs. reduction of 2.98 log U/mL; P=0.023). The AUROC for week 4 change of HBcrAg to predict FHR in HBeAg-negative patients was 0.789 (95% CI, 0.596-0.982).

CONCLUSION

Early on-treatment changes of serum HBV pgRNA and HBcrAg at 4 weeks predict HBsAg seroclearance or ≤100 IU/mL in NA-treated CHB patients upon long-term FU.

Anti-HBc IgG Levels: A Predictor of HBsAg Seroclearance in Chronic Hepatitis B Patients with Nucleos(t)ide Analogue-Induced HBeAg Seroclearance

BACKGROUND/AIMS

We investigated the efficiency of the indirect ratio of anti-HBc IgG at predicting HBsAg seroclearance in patients with nucleos(t)ide analogue (NA)-induced HBeAg seroclearance.

METHODS

We performed a retrospective study that included 366 chronic hepatitis B patients (March 2007 to December 2016) at a single tertiary hospital. These patients were HBsAg seropositive, and experienced NA-induced HBeAg seroclearance. The indirect ratio of light absorbance of anti-HBc IgG levels were measured with chemiluminescent microparticle immunoassay using the Architect Anti-HBc assay (Abbott Laboratories, IL, USA) as a qualitative method prior to antiviral therapy. We calculated the cumulative incidences of HBsAg seroclearance based on the anti-HBc IgG levels.

RESULTS

After a 10-year follow-up, 48 patients experienced HBsAg seroclearance (13.1%). Thirty-three of 179 patients who had an indirect ratio of light absorbance of anti-HBc IgG < 11 RLU (relative light unit) showed HBsAg seroclearance (18.4%); 15 of 187 patients who had an indirect ratio of light absorbance of anti-HBc IgG ≥ 11 RLU showed HBsAg seroclerance (8.0%) (p = 0.003). In multivariate analysis, age, and ALT at the time of HBeAg seroclearance were predictors of HBsAg seroclearance. Especially, the relative risk of HBsAg seroclearance in patients with baseline anti-HBc IgG levels < 11 RLU was 2.213 (95% CI, 1.220-4.014), compared to that in patients with higher levels of anti-HBc IgG at baseline (p = 0.009).

CONCLUSION

Using an indirect method for anti-HBc IgG levels, baseline anti-HBc IgG levels (< 11RLU), age (≥ 50 years), and ALT (≥ 40 IU/L) might be associated with HBsAg seroclearance in patients with NA-induced HBeAg seroclearance.

Serum hepatitis B core-related antigen as a surrogate marker of hepatitis B e antigen seroconversion in chronic hepatitis B

BACKGROUND

Quantitative hepatitis B core-related antigen (qHBcrAg) has a better correlation with intrahepatic hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) than HBV DNA or hepatitis B e antigen (HBeAg), but data are still lacking for its clinical application.

AIM

The aim was to investigate serum qHBcrAg levels in patients with chronic hepatitis B and assess the correlation of serum qHBcrAg with pregenomic RNA (pgRNA), cccDNA, and HBeAg seroconversion.

METHODS

This study was a secondary analysis of patients who underwent percutaneous liver biopsy between July 2014 and June 2019 in two multicenter randomized controlled clinical trials of peginterferon vs nucleos(t)ide analog (NUC)-based therapy (NCT03509688 and NCT03546530). Serum qHBcrAg, pgRNA, HBV DNA, hepatitis B core antigen, HBeAg, liver cccDNA, and HBV DNA were measured. The correlations of serum qHBcrAg with other biomarkers were analyzed.

RESULTS

A total of 139 patients were included. The mean qHBcrAg levels were 5.32 ± 1.18 log₁₀ U/mL at baseline and decreased during treatment (all P < 0.0001). Serum qHBcrAg levels were positively correlated with pgRNA (r = 0.597, P < 0.0001) and cccDNA (r = 0.527, P < 0.0001) levels. The correlation of serum qHBcrAg level and intrahepatic HBV DNA levels at baseline was weak but significant (r = 0.399, P < 0.0001). HBcrAg predicted HBeAg seroconversion, with areas under the receiver operating characteristics curve of 0.788 at 24 wk and 0.825 at 48 wk. Log HBcrAg at wk 24 and 48 was independently associated with HBeAg seroconversion [odds ratio (OR) = 2.402, 95% confidence interval (CI): 1.314-4.391, P = 0.004; OR = 3.587, 95%CI: 1.315-9.784, P = 0.013].

CONCLUSION

Serum HBcrAg levels were correlated with HBV virological markers and could be used to predict HBeAg seroconversion.

[The Clinical Significance and Mechanism of the Effect for Hepatitis B Virus Protein on Host Immune]

The cytotoxic effect targeting hepatitis B virus (HBV) infected hepatocytes from virus-specific cytotoxic T cells and the neutralizing antibodies secreted by virus-specific B cells play an important role in the immune control and elimination of HBV. In patients with chronic hepatitis B, the liver immune microenvironment usually presents a suppression state, and virus-specific immune cells are mostly exhausted. Studies on the interaction between HBV and host immunity during infection, especially the influence of various viral proteins on immune cell function, will contribute to understanding the mechanism of the chronicity of HBV infection, disease progression, and optimization of immunotherapy against HBV. The review summarized the suppressive effects of HBV viral proteins on the host innate immunity and adaptive immune system, to help us understanding the mechanism(s) relevant to the observation that a CHB patient with HBeAg loss and lower HBsAg level is more likley achieving functionall cure. and expect to provide new sights for accelerate virus clearance and achieve functional cure of chronic hepatitis B, by removing the HBV viral proteins and consequently, liberting host immune from suppression state.

Hepatitis B core-specific memory B cell responses associate with clinical parameters in patients with chronic HBV

BACKGROUND & AIMS

Little is known about the frequency, phenotype and function of HBV-specific B cells during chronic infection. Here we study HBcAg and HBsAg-specific B cells in different clinical phases of a chronic HBV infection.

METHODS

We included 118 treatment naïve and 34 nucleos(t)ide analogue-treated patients with chronic HBV and 23 healthy HBsAg-vaccinated controls. Global and HBV-specific B lymphocytes were examined by FACS using fluorescently labeled HBsAg and HBcAg as baits. Functional HBV-specific B cell responses were quantified in B cell ELISPOT assays. Anti-HBs and anti-HBc antibodies were measured in serum and in ELISPOT supernatant by ELISA.

RESULTS

Higher HBcAg-directed B cell responses were found in HBV clinical phases with elevated vs. low serum alanine aminotransferase (ALT) levels, irrespective of the HBeAg-status. In contrast, HBsAg-directed responses were lower and did not significantly fluctuate. In individual patients a mean 17.8-fold more circulating B cells target HBcAg than HBsAg baits. These HBcAg-specific B cells present a classical memory B cell profile and have slightly higher CD69 expression levels compared to global memory B cells. Viral suppression and ALT normalization upon treatment led to a numeric and functional reduction of HBcAg-specific B cell responses, accompanied by progressive decreases in serum anti-HBc antibodies.

CONCLUSION

HBcAg-specific memory B cells present a classical memory B cell phenotype, vary in number and function throughout HBV's natural history and are significantly reduced during antiviral treatment.

LAY SUMMARY

In recent years, studies examining the role of B cells during chronic hepatitis B virus infection have regained interest. We show that circulating B cells more often target the hepatitis B core antigen than the hepatitis surface antigen. Moreover, these hepatitis B core-specific B cells associate with the natural history of chronic HBV, and their responses decline during effective antiviral treatment.

Outcomes after hepatectomy of patients with positive HBcAb Non-B Non-C hepatocellular carcinoma compared to overt hepatitis B virus hepatocellular carcinoma

PURPOSE

Hepatitis B core antibody (HBcAb) positivity is regarded as a sensitive marker for occult and prior hepatitis B virus (HBV) infection. However, the prognosis of patients with HBcAb-positive in non-B, non-C hepatocellular carcinoma (NBNC-HCC) remains unclear. The study aimed to compare the clinicopathological characteristics of patients with HBcAb-positive NBNC-HCC to those with overt HBV (hepatitis B surface antigen positive) HCC.

METHODS

306 HCC patients underwent hepatectomy were divided into two groups: an overt HBV-HCC group and HBcAb-positive NBNC-HCC group. Then patients were analyzed using propensity score matching (PSM) to reduce selection bias. Clinicopathological characteristics and survival outcomes were compared between the two groups. Univariate and multivariate analysis for risk factors were also evaluated.

RESULTS

HBcAb-positive NBNC-HCC group showed comparable survival outcomes to the overt HBV-HCC group (3-year overall survival rates 66% vs 62%, 69% vs 53%; 3-year recurrence-free survival rates 49% vs 40%, 47% vs 37%; P > 0.05) before and after PSM. Patients with HBcAb-positive NBNC-HCC were older, had more complications, higher proportions of vascular invasion, and larger tumor sizes but lower proportions of cirrhosis, elevated alanine aminotransferase and prothrombin time.

CONCLUSIONS

HBcAb-positive NBNC-HCC group had more advanced tumors, but their prognosis was relatively comparable to that of the other group. Therefore, we believe that screening is also necessary in HBcAb-positive patients for early detection of HCC, especially in the elderly.

[Hepatitis B core antigen promotes invasion of hepatocellular carcinoma cell line HepG2.2.15 via Toll-like receptor 4]

Objective: To investigate the effect of hepatitis B core antigen (HBcAg) in promoting the invasion of hepatitis B virus (HBV)-related hepatocellular carcinoma cell line HepG2.2.15 and the role of Toll-like receptor 4 (TLR4) in the mechanism. Methods: TLR4 mRNA and protein expression in HepG2 cells and HepG2.2.15 cells was measured by reverse transcription real-time PCR and Western blot analysis, respectively. HepG2.2.15 cells were transfected with TLR4 specific small interfering RNA (siRNA) to silence TLR4 expression, and stimulated by recombinant HBcAg in culture. The invasion of cells was measured by Transwell invasion assay. The expression of TLR4 signaling pathway-related proteins in the cultured cells and proinflammatory cytokines in the supernatant was also determined. The student's t-test, one-way ANOVA, and SNK-q test were used for statistical analysis. Results: TLR4 mRNA and protein expression in HepG2.2.15 cells was significantly higher than that in HepG2 cells. TLR4 siRNA transfection remarkably down-regulated TLR4 expression in HepG2.2.15 cells. Inhibiting TLR4 expression and/or HBcAg stimulation did not affect the proliferation of HepG2.2.15 cells. However, HBcAg stimulation significantly increased the invasion ability of HepG2.2.15 cells and the secretion of proinflammatory cytokines [including interferon (IFN)-γ, interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α]. Inhibiting TLR4 expression significantly reduced HBcAg-induced cellular invasion. Meanwhile, HBcAg stimulation elevated the expression of MyD88 and TRIF in HepG2.2.15 cells. TLR4 silencing inhibited HBcAg-induced increase in the expression of MyD88, while it showed no significant impact on TRIF expression. Conclusion: HBcAg can promote the invasion of HepG2.2.15 cells. The TLR4/MyD88 signaling pathway may be involved in this process by inducing the expression of proinflammatory cytokines.

Development of meningococcal polysaccharide conjugate vaccine that can elicit long-lasting and strong cellular immune response with hepatitis B core antigen virus-like particles as a novel carrier protein

Neisseria meningitidis caused meningitis is life-threatening acute infection with high fatality and high frequency of severe sequelae. Meningococcal capsular polysaccharides can be used to prevent meningococcal disease; while conjugating the polysaccharides to carrier protein was found necessary to improve the immunogenicity and induce memory responses in infants and young children. Nevertheless, repeated administration of glycoconjugate vaccines might lead to carrier-induced epitope suppression due to limited number of carrier proteins. Here in this study, full-length hepatitis B core antigen virus-like particles (HBc VLPs) was used as a novel potential carrier protein for conjugation of meningococcal group C polysaccharides (CPS) with heterobifunctional polyethylene glycol (PEG) of different length (2, 5 and 10 kDa) as linkers. The physiochemical properties of the CPS-PEG-HBc conjugate vaccines were fully characterized. The TEM, DLS, native agarose gel electrophoresis, and HPLC analyses all confirmed the successful conjugation. As compared to plain CPS and the physical mixture of CPS and HBc, the immunization with the conjugate vaccines can generate about 10 times increase in CPS specific IgG titers with a significant boosting effect. HBc conjugation induced a shift to a Th1 cellular immune type response, as assessed by the increased IgG2a subclass production. In addition, vaccination of the conjugate vaccines elicited much enhanced avidity functional antibody and long-lasting immunological memory. IgG titers elicited by CPS-P2k-HBc, CPS-P5k-HBc and CPS-P10k-HBc at week 18 maintained 38.1%, 17.9% and 33.3% of their peak values. All these results demonstrated that HBc VLPs can be used as potential carrier protein to develop polysaccharide conjugate vaccines effective in eliciting long-lasting and strong cellular immune response.

Evaluation of the Protection Provided by Hepatitis B Vaccination in India

OBJECTIVE

In India, Hepatitis B vaccination is recommended at 6 wk except for hospital-deliveries. The authors examined protection afforded by the birth dose.

METHODS

A case-control study was done. HBsAg and HBcAb were tested in 2671 children, 1 to 5 y and HBsAb was evaluated in a subset of 1413 children. Vaccination history was recorded. Cases were HBsAg carriers. In another analysis, children who got infected (HBsAg and/or HBcAb positive) were considered as cases. Exposed were the unvaccinated. In another analysis, exposed were those vaccinated without the birth dose.

RESULTS

The odds ratio (OR) for HBsAg positivity with birth vaccination was 0.35 (95% CI 0.19-0.66); while with vaccination at 6 wk was 0.29 (95%CI 0.14-0.61), both compared to unvaccinated. Birth vaccination has no added protection when compared to the unvaccinated. Unvaccinated children in index study had HBsAg positivity of 4.38%. The number needed to treat (NNT) to prevent one case of HBsAg positivity was 32.6 (95% CI, 20.9 to 73.6). The odds of getting HBV infection was 0.42 (CI 0.25-0.68) with birth dose and 0.49 (CI 0.30-0.82) without the birth dose compared to the unvaccinated. Protective antibody (HBsAb) was present in about 70% of the vaccinated. In the unimmunised, in the first 2 y HBsAb protection was present in 40%. The odds ratio (OR) for HBsAb in the fully vaccinated between 4 and 5 y was 1.4 (95%CI 0.9-2.18) compared to the unvaccinated.

CONCLUSIONS

The present study lends support to the pragmatic approach of the Government to vaccinate babies born at home starting at 6 wk.

Humoral Immune Response in Mice Elicited by Combined Yeast-Derived Hepatitis B Virus Core, Surface, and Mosaic Surface Antigens

BACKGROUND

Although successful, the second-generation hepatitis B vaccine programs around the world have a small group of immunized individuals that does not respond efficiently to the vaccination. Other issues of these vaccines are individuals that are low or nonresponders and/or have incomplete protection against heterologous hepatitis B virus (HBV) genotypes/subtypes and against HBV escape mutants. In addition, there are approximately 240 million people chronically infected with HBV worldwide and 620,000 deaths per year caused by the infection.

METHODS

In this study we developed three Hansenula polymorpha plasmids containing the following sequences: (a) HBsAg subtype ayw, (b) HBcAg sequence subtype adw2, and (c) chimeric HBsAg (adw4/ ayw) - preS1 (adw2) - 3 repetitions of preS2 (genotypes A, B, and C). The sequences were successfully expressed and the antigens purified. Using Balb/c mice the antigens were tested in different dosage combinations.

RESULTS

Three antigens were obtained at a high purity level and with high reproducibility. We also assessed their immunogenic properties, showing that the antigens, individually or in combination, generated anti-HBs, anti-preS1, anti-preS2, and anti-HBc antibodies efficiently in mice.

CONCLUSIONS

The formulation tests showed that a combination of 0.02 μg of HBs, 0.2 μg of preS1-preS2-HBs, and 0.02 μg of HBc was effective in eliciting specific antibodies in mice.

Hepatitis B Core Antibody Negativity in a Chronic Hepatitis B Infected Patient: Report of an Unusual Serological Pattern

Diagnosis of Hepatitis B Virus (HBV) infection is established by the presence of various hepatitis B serological and molecular markers. Expression of these serological markers may vary in natural course of HBV infection. We report a case of an unusual HBV serological pattern in a Chronic Hepatitis B (CHB) infected patient demonstrating absence of Hepatitis B core Antibody (Anti-HBc) in spite of presence of Hepatitis B surface Antigen (HBsAg) and HBV DNA. Since, anti-HBc represents a reliable serological marker for past exposure of HBV infection, therefore we emphasize on the presence of such unusual serological pattern which could lead to doubts in the interpretation of results.

Intrahepatic distribution of hepatitis B virus antigens in patients with and without hepatocellular carcinoma

AIM: To study the intrahepatic expression of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) in chronic hepatitis B patients with and without hepatocellular carcinoma.

METHODS: A total of 33 chronic hepatitis B patients (mean age of 40.3 ± 2.5 years), comprising of 14 HBeAg positive and 19 HBeAg negative patients; and 13 patients with hepatitis B virus related hepatocellular carcinoma (mean age of 49.6 ± 4.7 years), were included in our study. Immunohistochemical staining for HBcAg and HBsAg was done using standard streptavidin-biotin-immunoperoxidase technique on paraffin-embedded liver biopsies. The HBcAg and HBsAg staining distributions and patterns were described according to a modified classification system.

RESULTS: Compared to the HBeAg negative patients, the HBeAg positive patients were younger, had higher mean HBV DNA and alanine transaminases levels. All the HBeAg positive patients had intrahepatic HBcAg staining; predominantly with “diffuse” distribution (79%) and “mixed cytoplasmic/nuclear” pattern (79%). In comparison, only 5% of the HBeAg-negative patients had intrahepatic HBcAg staining. However, the intrahepatic HBsAg staining has wider distribution among the HBeAg negative patients, namely; majority of the HBeAg negative cases had “patchy” HBsAg distribution compared to “rare” distribution among the HBeAg positive cases. All but one patient with HCC were HBeAg negative with either undetectable HBV DNA or very low level of viremia. Intrahepatic HBcAg and HBsAg were seen in 13 (100%) and 10 (77%) of the HCC patients respectively. Interestingly, among the 9 HCC patients on anti-viral therapy with suppressed HBV DNA, HBcAg and HBsAg were detected in tumor tissues but not the adjacent liver in 4 (44%) and 1 (11%) patient respectively.

CONCLUSION: Isolated intrahepatic HBcAg and HBsAg can be present in tumors of patients with suppressed HBV DNA on antiviral therapy; that may predispose them to cancer development.

Lentiviral vector encoding ubiquitinated hepatitis B core antigen induces potent cellular immune responses and therapeutic immunity in HBV transgenic mice

Predominant T helper cell type 1 (Th1) immune responses accompanied by boosted HBV-specific cytotoxic T lymphocyte (CTL) activity are essential for the clearance of hepatitis B virus (HBV) in chronic hepatitis B (CHB) patients. Ubiquitin (Ub) serves as a signal for the target protein to be recognized and degraded through the ubiquitin-proteasome system (UPS). Ubiquitinated hepatitis B core antigen (Ub-HBcAg) has been proved to be efficiently degraded into the peptides, which can be presented by major histocompatibility complex (MHC) class I resulting in stimulating cell-mediated responses. In the present study, lentiviral vectors encoding Ub-HBcAg (LV-Ub-HBcAg) were designed and constructed as a therapeutic vaccine for immunotherapy. HBcAg-specific cellular immune responses and anti-viral effects induced by LV-Ub-HBcAg were evaluated in HBV transgenic mice. We demonstrated that immunization with LV-Ub-HBcAg promoted the secretion of cytokines interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), generated remarkably high percentages of IFN-γ-secreting CD8(+) T cells and CD4(+) T cells, and enhanced HBcAg-specific CTL activity in HBV transgenic mice. More importantly, vaccination with LV-Ub-HBcAg could efficiently decreased the levels of serum hepatitis B surface antigen (HBsAg), HBV DNA and the expression of HBsAg and HBcAg in liver tissues of HBV transgenic mice. In addition, LV-Ub-HBcAg could upregulate the expression of T cell-specific T-box transcription factor (T-bet) and downregulate the expression of GATA-binding protein 3 (GATA-3) in spleen T lymphocytes. The therapeutic vaccine LV-Ub-HBcAg could break immune tolerance, and induce potent HBcAg specific cellular immune responses and therapeutic effects in HBV transgenic mice.

Meeting report VLPNPV: Session 5: Plant based technology

The VLPNPV 2014 Conference that was convened at the Salk institute was the second conference of its kind to focus on advances in production, purification, and delivery of virus-like particles (VLPs) and nanoparticles. Many exciting developments were reported and discussed in this interdisciplinary arena, but here we report specifically on the contributions of plant-based platforms to VLP vaccine technology as reported in the section of the conference devoted to the topic as well in additional presentations throughout the meeting. The increasing popularity of plant production platforms is due to their lower cost, scalability, and lack of contaminating animal pathogens seen with other systems. Reports include production of complex VLPs consisting of 4 proteins expressed at finely-tuned expression levels, a prime-boost strategy for HIV vaccination using plant-made VLPs and a live viral vector, and the characterization and development of plant viral nanoparticles for use in cancer vaccines, drug delivery, and bioimaging.

Transbody against hepatitis B virus core protein inhibits hepatitis B virus replication in vitro

Hepatitis B virus (HBV) infection is one of the major causes of chronic liver diseases. The current therapeutics show limited efficacy. In the HBV life cycle, virus core antigen (HBcAg) plays important multiple roles. Blocking the pleiotropic functions of HBcAg may thus represent a promising strategy for anti-HBV replication. In this study, monoclonal antibody (MAb) against core antigen of human HBV was coupled with TAT protein transduction domain (TAT PTD) to form transbody, and the effect on virus replication was evaluated in vitro. The HBV transbody, HBcMAb-TAT PTD conjugate, recognized HBcAg and retained cell-penetrating activity in living cells. In HBV-transfected liver cell line HepG2.2.15, HBV transbody suppressed not only the extracellular HBsAg, HBeAg and HBV DNA, but also the intracellular HBsAg, HBeAg, HBcAg and HBV DNA in a dose-dependent manner. These results indicate that the transbody prepared possesses readily cell-penetrating ability and potent antiviral activity, providing a novel approach, a cell-permeable antibody against HBcAg, for the treatment of HBV infection.

Hepatitis B Core Antigen in Hepatocytes of Chronic Hepatitis B: Comparison between Indirect Immunofluorescence and Immunoperoxidase Method

Background

Hepatitis B virus (HBV) infection has many faces. Precore and core promoter mutants resemble inactive carrier status. The identification of hepatitis B core antigen (HBcAg) in hepatocytes may have variable clinical significance. The present study was undertaken to detect HBcAg in chronic hepatitis B (CHB) patients and to assess the efficacy of detection system by indirect immunofluorescence (IIF) and indirect immunoperoxidase (IIP).

Materials and methods

The study was done in 70 chronic HBV-infected patients. Out of 70 patients, eight (11.4%) were hepatitis B e antigen (HBeAg) positive and 62 (88.57%) were HBeAg negative. Hepatitis B core antigen was detected by indirect immunofluorescence (IIF) and indirect immunoperoxidase (IIP) methods in liver tissue.

Results

All HBeAg positive patients expressed HBcAg by both IIF and IIP methods. Out of 62 patients with HBeAg-negative CHB, HBcAg was detected by IIF in 55 (88.7%) patients and by IIP in 51 (82.26%) patients. A positive relation among viral load and HBcAg detection was also found. This was more evident in the case of HBeAg negative patients and showed a positive relation with HBV DNA levels.

Conclusion

Hepatitis B core antigen can be detected using the IIF from formalin fixed paraffin block preparation and also by IIP method. This seems to reflect the magnitudes of HBV replication in CHB.

How to cite this article

Raihan R, Tabassum S, Al-Mahtab M, Nessa A, Jahan M, Kabir CMS, Kamal M, Aguilar JC. Hepatitis B Core Antigen in Hepatocytes of Chronic Hepatitis B: Comparison between Indirect Immunofluorescence and Immunoperoxidase Method. Euroasian J Hepato-Gastroenterol 2015;5(1):7-10.

Ubiquitin-hepatitis B core antigen-cytoplasmic transduction peptide enhances HBV-specific humoral and CTL immune responses in vivo

Therapeutic strategies based on an enhanced hepatitis B virus (HBV)-specific cytotoxic T lymphocyte (CTL) activity may eradicate HBV. We previously verified that a fusion protein ubiquitin (Ub)-hepatitis B core antigen (HBcAg)-cytoplasmic transduction peptide (CTP) can enter the cytoplasm of dendritic cells and enhance T cell response to generate HBV-specific CTLs efficiently in vitro. Ub, a marker of protein degradation, may promote the generation of peptides appropriate for major histocompatibility complex class I presentation. In the present study, the specific immune responses of the fusion protein Ub-HBcAg-CTP in BALB/c mice were evaluated and the underlying mechanisms were investigated. Results showed that Ub-HBcAg-CTP increased the anti-HBcAg titer and produced the cytokines IFN-γ and IL-2. This fusion protein also induced higher percentages of IFN-γ(+)CD8(+) cells and specific CTL responses. Ub-HBcAg-CTP could also upregulate the expressions of Jak2, Tyk2, STAT1, and STAT4 in T lymphocytes. In conclusion, Ub-HBcAg-CTP enhanced cellular and humoral immune responses and induced robust HBV-specific CTL activities in BALB/c mice.

Hepatitis B core antigen expression in hepatocytes reflects viral response to entecavir in chronic hepatitis B patients

Background/Aims

Hepatitis B core antigen is known to be a major target for virus-specific T cells and also reflects the progression of liver dissease and viral replication. Hepatitis B core antigen expression in hepatocytes leads to altered histological activity, viral replication, and immune response. The purpose of this study is to evaluate whether the topographical distribution of hepatitis B core antigen expression can predict the viral response to entecavir in patients with chronic hepatitis B.

Methods

We enrolled 91 patients with treatment-naïve chronic hepatitis B. All the patients underwent liver biopsy, and the existence and pattern of hepatitis B core antigen evaluated by immunohistochemistry. All patients received 0.5 mg of entecavir daily following a liver biopsy. We checked the viral response at 3, 6, and 12 months during antiviral therapy.

Results

Of the 91 patients, 64 (70.3%) had hepatitis B core antigen expression. Of the subcellular patterns, the mixed type was dominant (n=48, 75%). The viral response was significantly higher in the hepatitis B core antigen-negative group than in the hepatitis B core antigen-positive group (88.9% and 54.7%, respectively; p=0.001) after 12 months of entecavir therapy.

Conclusions

Chronic hepatitis B patients who are hepatitis B core antigen-negative have a better response to entecavir therapy than do hepatitis B core antigen-positive patients.

Ubiquitin conjugation of hepatitis B virus core antigen DNA vaccine leads to enhanced cell-mediated immune response in BALB/c mice

BACKGROUND

Nearly 350 million persons worldwide are chronically infected with hepatitis B virus (HBV). Ubiquitin (Ub) is a highly conserved small regulatory protein, ubiquitous in eukaryotes, that usually serves as a signal for the target protein that is recognised and degraded in proteasomes . The Ub-mediated processing of antigens is rapid and efficient and stimulates cell-mediated immune responses. Accordingly, Ub-mediated processing of antigens has been widely used in chronic-infection and cancer studies to improve immune response.

OBJECTIVES

Many clinical trials have shown that DNA vaccine potency needs to be greatly enhanced. Here, we report a new strategy for designing an HBV DNA vaccine using the ubiquitin (Ub) sequence. The aim of this study was to investigate a novel DNA vaccination, based on the expression of HBV core antigen (HBcAg), fused to Ub to enhance DNA vaccine potency.

MATERIALS AND METHODS

Mouse ubiquitin fused to the HBcAg gene and cloned into the eukaryotic vector pcDNA3.1 (-). BALB/c mice were immunized with recombinant pUb-HBcAg or pHBcAg DNA vaccine. Lymphocyte proliferation assay, intracellular IFN-γ assay, CTL cytotoxicity assay, and antibody assay were performed to analyze the cellular and humoral immune responses to our DNA constructs.

RESULTS

HBcAg was expressed effectively in the COS-7 cells that were transiently transfected with pUb-HBcAg. Strong anti-HBc IgG responses were elicited in mice that were immunized with pUb-HBcAg. The endpoint titers of anti-HBc peaked at 1:656100 on the 42nd day after the third immunization. pUb-HBcAg stimulated greater lymphocyte proliferation and induced higher levels of IL-2 and IFN-γ and a greater percentage of HBcAg-specific CD8+ T cells in mice than pHBcAg. In the CTL assay, the specific lysis rate reached 56.5% at an effector:target ratio of 50:1 in mice that were immunized with pUb-HBcAg.

CONCLUSIONS

pUb-HBcAg elicits specific anti-HBc responses and induces HBc-specific CTL responses in immunized BALB/c mice. Our results imply that Ub can be used as a molecular adjuvant that enhances the potency of DNA vaccines.

Ubiquitin conjugation of hepatitis B virus core antigen DNA vaccine leads to enhanced cell-mediated immune response in BALB/c mice

BACKGROUND

Nearly 350 million persons worldwide are chronically infected with hepatitis B virus (HBV). Ubiquitin (Ub) is a highly conserved small regulatory protein, ubiquitous in eukaryotes, that usually serves as a signal for the target protein that is recognised and degraded in proteasomes . The Ub-mediated processing of antigens is rapid and efficient and stimulates cell-mediated immune responses. Accordingly, Ub-mediated processing of antigens has been widely used in chronic-infection and cancer studies to improve immune response.

OBJECTIVES

Many clinical trials have shown that DNA vaccine potency needs to be greatly enhanced. Here, we report a new strategy for designing an HBV DNA vaccine using the ubiquitin (Ub) sequence. The aim of this study was to investigate a novel DNA vaccination, based on the expression of HBV core antigen (HBcAg), fused to Ub to enhance DNA vaccine potency.

MATERIALS AND METHODS

Mouse ubiquitin fused to the HBcAg gene and cloned into the eukaryotic vector pcDNA3.1 (-). BALB/c mice were immunized with recombinant pUb-HBcAg or pHBcAg DNA vaccine. Lymphocyte proliferation assay, intracellular IFN-γ assay, CTL cytotoxicity assay, and antibody assay were performed to analyze the cellular and humoral immune responses to our DNA constructs.

RESULTS

HBcAg was expressed effectively in the COS-7 cells that were transiently transfected with pUb-HBcAg. Strong anti-HBc IgG responses were elicited in mice that were immunized with pUb-HBcAg. The endpoint titers of anti-HBc peaked at 1:656100 on the 42nd day after the third immunization. pUb-HBcAg stimulated greater lymphocyte proliferation and induced higher levels of IL-2 and IFN-γ and a greater percentage of HBcAg-specific CD8+ T cells in mice than pHBcAg. In the CTL assay, the specific lysis rate reached 56.5% at an effector:target ratio of 50:1 in mice that were immunized with pUb-HBcAg.

CONCLUSIONS

pUb-HBcAg elicits specific anti-HBc responses and induces HBc-specific CTL responses in immunized BALB/c mice. Our results imply that Ub can be used as a molecular adjuvant that enhances the potency of DNA vaccines.

Anti-HBc screening in Indian blood donors: Still an unresolved issue

AIM: To study the seroprevalence of antibody to hepatitis B core antigen (anti-HBc) in healthy blood donors negative for HBsAg and to evaluate whether anti-HBc detection could be adopted in India as a screening assay for HBV in addition to HBsAg.

METHODS: A total of 1700 serum samples collected from HBsAg-negative healthy blood donors were tested for the presence of anti-HBc antibody (IgM + IgG). All samples reactive for anti-HBc antibody were then investigated for presence of anti-HBs and for liver function tests (LFTs). One hundred serum samples reactive for anti-HBc were tested for HBV DNA by PCR method.

RESULTS: Out of 1700 samples tested, 142 (8.4%) blood samples were found to be reactive for anti-HBc. It was significantly lower in voluntary (6.9%) as compared to replacement donors (10.4%, P = 0.011). Seventy-two (50.7%) anti-HBc reactive samples were also reactive for anti-HBs with levels > 10 mIU/mL and 70 (49.3%) samples were non-reactive for anti-HBs, these units were labeled as anti-HBc-only. These 142 anti-HBc reactive units were also tested for liver function test. HBV DNA was detected in only 1 of 100 samples tested.

CONCLUSION: Keeping in view that 8%-18% of donor population in India is anti-HBc reactive, inclusion of anti-HBc testing will lead to high discard rate. Anti-HBs as proposed previously does not seem to predict clearance of the virus. Cost effectiveness of introducing universal anti-HBc screening and discarding large number of blood units versus considering ID NAT (Individual donor nuclic acid testing) needs to be assessed.

Screening of proteins binding to hepatitis B core antigen from human pancreas cDNA library by yeast two-hybrid system

AIM: To screen proteins in human pancreas cDNA library interacting with hepatitis B core antigen (HbcAg) by yeast two-hybrid system.

METHODS: After amplification, purification, and identification, the human pancreas cDNA library plasmid was transformed into yeast Y187. Thereafter, the reconstructed bait plasmid (pGBKT7-HBcAg) was transformed into yeast cells AH109. Then, the transformed AH109 was mated with Y187 that contained the library plasmid. The diploid yeast cells were plated on nutrient deficiency medium SD/-Trp/-Leu/-His/-Ade and SD/-Trp/-Leu/-His/-Ade containing X-α-gal for selecting. The plasmids in diploid yeast cells were extracted and electrotransformed into E.coli DH5α. The plasmids in DH5α were extracted, sequenced and analyzed by bioinformatic methods.

RESULTS: The human pancreas cDNA library was constructed successfully. The reconstructed bait plasmid (pGBKT7-HBcAg) was transformed into yeast cells AH109 successfully. Nine proteins interacting with HBcAg were screened, and their sequences were homologous with human pancreatic lipase (PNLIP), CEL, CTRC, trypsinogen, carboxypeptidase 1 (CPB1), human complete mitochondrial genome, human pancreatic elastinase 2A, human complement lipase (CLPS) and human ribosomal protein (RPL10A).

CONCLUSION: HBcAg protein may be related with the exocrine pancreatic function and metabolism of glucose or lipid. HBV infection probably leads to metabolic abnormality or metabolic diseases through interacting with pancreatic enzymes.