Recombinant Plasmid for Persistent HBV Antigen Expression
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Solution Overview
Problem
Current animal models for hepatitis B virus (HBV) infection studies, such as HBV transgenic mice, fail to accurately replicate human HBV infection and immune response, limiting their usefulness for long-term monitoring and drug evaluation due to short-term acute liver inflammatory responses and immune system clearance.
Innovation Solution
A recombinant plasmid using an adeno-associated virus (AAV) vector and a replication-competent HBV genome fragment is delivered to immunocompetent mice to persistently express HBV antigens, mimicking the episomal form of natural HBV infection and allowing for extended HBV antigen production and replication, enabling chronic hepatitis studies and drug evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HBV transgenic mice are used to study HBV infection, then the model can be established with stable viral genome integration, but the immune response does not resemble human hepatitis and the model is not ideal for studying HBV tolerance and clearance
Solution Approach 1:
The patent divides the HBV genome into essential functional segments (surface antigen, core antigen, polymerase, precore) and inserts them into a transgenic construct that mimics natural HBV infection mechanisms, allowing selective expression that reproduces human-like immune responses while maintaining genetic stability
Solution Approach 2:
The patent uses a specially designed transgenic construct as an intermediary that bridges the gap between complete HBV genome integration and partial antigen expression, enabling the model to exhibit both stable viral persistence and human-resembling immune responses suitable for studying tolerance and clearance
2Reliability
If recombinant plasmid is injected to induce acute hepatitis model, then immune response resembling human hepatitis can be elicited, but the response is short-term and clears after 14 days limiting long-term monitoring
Solution Approach 1:
The patent incorporates HBV antigen genes into the mouse germline during transgenic construction, so that antigen expression is pre-programmed to begin at birth and continue throughout life, eliminating the need for repeated plasmid injections and ensuring long-term persistent expression
Solution Approach 2:
The patent changes the temporal expression parameter from acute/transient (14 days) to chronic/lifelong by using transgenic integration, while maintaining the quality of immune response resemblance to human hepatitis through carefully selected viral gene sequences
3Duration of action of stationary object
If whole-genome HBV transgenic mice are created with stable viral genome integration, then persistent antigen expression is achieved, but the model exhibits HBV antigen tolerance and does not show normal immune response
Solution Approach 1:
The patent applies local quality by selectively including only specific functional regions of the HBV genome (surface antigen, core antigen, polymerase, precore) rather than the entire genome, allowing persistent expression in liver tissue while maintaining the ability to elicit normal immune responses through controlled antigen presentation
Data Source
AI summary
Disclosed is a recombinant plasmid for expressing hepatitis B viral antigens in vivo, comprising an adeno-associated virus (AVV) vector and a replication-competent hepatitis B virus genome fragment. Mice hydrodynamically injected with the recombinant plasmid of the present invention show persistent expression of hepatitis B viral antigens for more than 6 months in the hepatocytes, thus a immuno-competent mouse model for persistent expression of hepatitis B antigens and also for human chronic hepatitis B virus infection is established, which can be applied in evaluation and elucidation of mechanism of chronic hepatitis and anti-viral drug discovery research.