Technical Services

HBV Infection-Related Technical Services

I. Model Overview

The life cycle of the Hepatitis B Virus (HBV) is a highly coordinated molecular biological process, involving the following key stages and molecular events:

1. Viral Entry

2. Formation of Covalently Closed Circular DNA (cccDNA)

3. Viral Transcription

4. Nucleocapsid Assembly and Reverse Transcription

5. Virion Maturation and Secretion

6. Secondary Infection and Transmission

The complete life cycle of HBV is illustrated below:

HBV Infection Models: Types and Their Advantages/Limitations

1. Primary Hepatocyte Models (Gold Standard)

• Human Primary Hepatocytes (PHH) and Tupaia Hepatocytes:

• Exhibit natural HBV susceptibility with high infection efficiency.

• Crab-Eating Monkey Primary Hepatocytes + hNTCP:

• Support HBV infection.

• Porcine Primary Hepatocytes (PPH) + hNTCP:

• Enable efficient HBV infection (Mol Med Rep. 2019 Oct;20(4):3820-3828, with Dr. Ming Zhou (Liwo Bio) as the first author; Hepatology. 2017 Sep;66(3):703-716).

Advantages:

• Directly isolated from human or animal livers, retaining natural metabolic functions and viral receptor activity.

• Ideal for studying HBV replication, drug metabolism, and cccDNA clearance mechanisms.

Limitations:

• Short survival time (<14 days), limiting long-term observation of chronic infection.

• Complex protocols and high inter-donor variability.

2. Hepatoma Cell Line Models

Common Models:

• HepG2.2.15 and HepAD38: Primarily used for HBV virion production.

• Huh7D-hNTCP: Optimized for HBV infection studies and drug evaluation.

Key Features:

• Huh7D-hNTCP exhibits higher HBV infection efficiency compared to HepG2-hNTCP (Virol Sin. 2017 Dec;32(6):465-475, with Dr. Ming Zhou (LV Biotech) as the first author).

Advantages:

• Easy to culture and highly reproducible.

• Ideal for high-throughput drug screening and viral life cycle research.

Limitations:

• Lack normal hepatocyte polarity and a functional immune microenvironment.

• Cannot replicate host immune responses observed in natural HBV infections.

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3. Humanized Liver Mouse Models

Humanized liver mouse models are generated by transplanting human primary hepatocytes or liver progenitor cells into genetically modified immunodeficient mice (e.g., FRG, uPA strains), enabling the reconstitution of functional humanized livers. These models support HBV infection, drug metabolism studies, and liver disease mechanism research, and can mimic chronic hepatitis, fibrosis, and other pathological processes. They are widely used for antiviral drug screening and host-virus interaction studies.

Key Features

• Advantages:

• Recapitulate human liver physiology and support the full HBV infection cycle, including chronic hepatitis, fibrosis, and antiviral therapy evaluation.

• Overcome limitations of in vitro models by replicating human liver-specific microenvironments.

• Limitations:

• High cost and technical complexity in model generation.

• Lack of a functional immune system, restricting studies on immune-mediated pathogenesis.

4. 3D Spheroid/mini-liver Infection Model

The 3D spheroid/mini-liver model mimics the liver microenvironment, offering a highly biomimetic platform for studying HBV infection mechanisms and evaluating antiviral drugs. These spheroids are typically constructed by co-culturing primary human hepatocytes (PHH) with Kupffer cells and stellate cells, forming polarized structures and intercellular communication networks.

Key Advantages Over 2D Models

• Sustained NTCP expression: Maintains long-term, high-level expression of the HBV receptor NTCP, enabling the complete HBV life cycle (entry, replication, virion secretion).

• Stable cccDNA persistence: Supports prolonged stability of HBV covalently closed circular DNA (cccDNA), critical for modeling chronic infection.

• Extended culture duration: Viable for up to 2 months (or longer based on experimental conditions), as validated by our team.

Applications

• HBV infection dynamics: Study viral entry, replication, and immune evasion strategies.

• Antiviral drug screening: Evaluate drug efficacy and resistance in a physiologically relevant system.

• Chronic infection modeling: Investigate cccDNA maintenance and therapeutic clearance strategies.

Technical Strengths

• Biomimetic complexity: Recapitulates cell-cell interactions, metabolic zonation, and liver-specific functions.

• High reproducibility: Standardized protocols ensure consistent spheroid formation and functionality.

• Customizable co-culture: Incorporate immune cells or stromal components to study host-pathogen interactions.

Why Choose This Model?

Developed using proprietary 3D culture technology, this platform bridges the gap between simplistic 2D systems and costly animal models, delivering human-relevant data with high translational value

II. Service Credentials, Facilities, and Team

Certified Laboratory Infrastructure

• GMP-Compliant BSL-2 Lab: Operates in a Biosafety Level 2 (BSL-2) laboratory registered with the National Health Commission, authorized for handling pathogens including HBV, lentiviruses, and human/animal-derived samples.

• Regulatory Compliance: Adheres to strict biosafety protocols and quality management systems.

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Advanced Equipment and Facilities

• Cutting-Edge Instrumentation: Over RMB 20 million+ invested in state-of-the-art equipment, including:

• Confocal laser scanning microscope

• High-speed fluorescence-activated cell sorting (FACS) systems

• Ultracentrifuges

• Real-time quantitative PCR systems

• Automated cell culture platforms

• Dedicated Infrastructure: Climate-controlled workspaces, pathogen containment zones, and advanced imaging suites.

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Expert Team

• Leadership: Guided by globally recognized scientists, including:

• Fellow of the American Institute for Medical and Biological Engineering (AIMBE)

• Recipients of China’s National "Young Thousand Talents" Program and Shenzhen High-Level Talent Awards.

• Dr. Ming Zhou – Principal Scientist:

• Education: Ph.D. in Virology from the Wuhan Institute of Virology, Chinese Academy of Sciences.

• Experience: 14+ years of expertise in HBV pathogenesis and therapeutic development.

• Funding: Principal investigator for 7+ national and regional grants, including projects from the National Natural Science Foundation of China, Guangdong Provincial Department of Science and Technology, and Shenzhen Science and Technology Innovation Commission.

• Publications: 10+ first/corresponding-author papers in high-impact SCI journals.

Core Competencies

• End-to-End Solutions: From model development (e.g., 3D mini-livers, humanized mice) to preclinical data generation.

• Translational Expertise: Bridging basic research with clinical applications through physiologically relevant models.

• Collaborative Innovation: Partnering with academia and industry to accelerate HBV cure discovery.