A unique B cell epitope-based particulate vaccine shows effective suppression of hepatitis B surface antigen in mice.

OBJECTIVE: This study aimed to develop a novel therapeutic vaccine based on a unique B cell epitope and investigate its therapeutic potential against chronic hepatitis B (CHB) in animal models. METHODS: A series of peptides and carrier proteins were evaluated in HBV-tolerant mice to obtain an optimised therapeutic molecule. The immunogenicity, therapeutic efficacy and mechanism of the candidate were investigated systematically. RESULTS: Among the HBsAg-aa119-125-containing peptides evaluated in this study, HBsAg-aa113-135 (SEQ13) exhibited the most striking therapeutic effects. A novel immunoenhanced virus-like particle carrier (CR-T3) derived from the roundleaf bat HBV core antigen (RBHBcAg) was created and used to display SEQ13, forming candidate molecule CR-T3-SEQ13. Multiple copies of SEQ13 displayed on the surface of this particulate antigen promote the induction of a potent anti-HBs antibody response in mice, rabbits and cynomolgus monkeys. Sera and purified polyclonal IgG from the immunised animals neutralised HBV infection in vitro and mediated efficient HBV/hepatitis B virus surface antigen (HBsAg) clearance in the mice. CR-T3-SEQ13-based vaccination induced long-term suppression of HBsAg and HBV DNA in HBV transgenic mice and eradicated the virus completely in hydrodynamic-based HBV carrier mice. The suppressive effects on HBsAg were strongly correlated with the anti-HBs level after vaccination, suggesting that the main mechanism of CR-T3-SEQ13 vaccination therapy was the induction of a SEQ13-specific antibody response that mediated HBV/HBsAg clearance. CONCLUSIONS: The novel particulate protein CR-T3-SEQ13 suppressed HBsAg effectively through induction of a humoural immune response in HBV-tolerant mice. This B cell epitope-based therapeutic vaccine may provide a novel immunotherapeutic agent against chronic HBV infection in humans.

Structural and functional analyses of hepatitis B virus X protein BH3-like domain and Bcl-xL interaction.

Hepatitis B virus (HBV) X protein, HBx, interacts with anti-apoptotic Bcl-2 and Bcl-xL proteins through its BH3-like motif to promote HBV replication and cytotoxicity. Here we report the crystal structure of HBx BH3-like motif in complex with Bcl-xL where the BH3-like motif adopts a short α-helix to snuggle into a hydrophobic pocket in Bcl-xL via its noncanonical Trp120 residue and conserved Leu123 residue. This binding pocket is ~2 Å away from the canonical BH3-only binding pocket in structures of Bcl-xL with proapoptotic BH3-only proteins. Mutations altering Trp120 and Leu123 in HBx impair its binding to Bcl-xL in vitro and HBV replication in vivo, confirming the importance of this motif to HBV. A HBx BH3-like peptide, HBx-aa113-135, restores HBV replication from a HBx-null HBV replicon, while a shorter peptide, HBx-aa118-127, inhibits HBV replication. These results provide crucial structural and functional insights into drug designs for inhibiting HBV replication and treating HBV patients.

[Outcome after surgery preserving pharynx and larynx for cervical esophageal cancer].

OBJECTIVE: To evaluate the long-term survival of multidisciplinary treatment based on thoracic surgery for cervical esophageal squamous cell carcinoma. METHODS: The clinical characters and follow-up data of forty-one cervical esophageal cancer patients who accepted multidisciplinary treatment based on surgery with preservation of pharynx and larynx were retrospectively reviewed, and the long-term survival was compared with 480 non-cervical esophageal cancers who accepted surgery in the same period done by the same surgical team. RESULTS: There were 28 males and 13 females with a mean age of 62 years old. In the cervical esophageal cancer group, 30 patients accepted neoadjuvant chemotherapy, 25 patients accepted adjuvant chemotherapy, and 21 patients accepted both. Six patients received postoperative radiation. Four patients underwent exploratory surgery alone, and 37 cases underwent radical surgery and cervical anastomosis. One case died during the perioperative period. The 1-, 3-, 5- and 8-year survival rates were 96.8%, 52.6%, 35.1%, and 35.1% in the 36 patients with cervical esophageal cancer who underwent radical surgery, and were 85.0%, 54.3%, 45.0%, and 36.7% respectively in the 457 non-cervical esophageal cancer patients. There was no significant difference between the cervical group and non-cervical group(P=0.91). CONCLUSION: Cervical esophageal cancer should be treated in a multidisciplinary approach to obtain satisfactory long-term outcomes.