Recombinant Hansenula polymorpha Hepatitis B Vaccine
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Solution Overview
Problem
Current hepatitis B vaccines face challenges in effectively reversing immune tolerance and achieving complete elimination of the hepatitis B virus and its covalently closed circular DNA, leading to persistent infections and limited therapeutic success, especially due to low expression levels of HBsAg in recombinant Hansenula polymorpha cells and insufficient CTL epitopes.
Innovation Solution
A hepatitis B therapeutic vaccine is developed using inactivated whole recombinant Hansenula polymorpha cells expressing HBsAg with 19 specific CTL epitopes, achieving high-level expression and optimized heat inactivation to enhance immune response and safety, thereby maximizing the amount of HBsAg per cell dose and targeting HBV-infected hepatocytes effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recombinant Hansenula polymorpha cells are used to express HBsAg, then the vaccine can be produced through genetic engineering, but the expression level of HBsAg is low and the number of CTL epitopes is insufficient
Solution Approach 1:
The patent optimizes multiple parameters including: (1) modifying the signal peptide sequence to enhance secretion efficiency, (2) adjusting fermentation conditions (temperature, pH, dissolved oxygen) to maximize HBsAg expression, (3) selecting optimal induction time and methanol concentration, (4) optimizing cell concentration and culture volume. These parameter changes collectively increase HBsAg expression level and CTL epitope presentation while maintaining therapeutic efficacy
Solution Approach 2:
The patent implements dynamic control of the expression system through: (1) inducible promoter activation at optimal growth phase, (2) dynamic adjustment of methanol feeding rate to balance cell growth and protein expression, (3) real-time monitoring and adjustment of fermentation parameters. This dynamic approach maximizes HBsAg production while ensuring sufficient CTL epitope display for effective therapy
2Reliability
If the amount of HBsAg injected is increased to maximize immune response, then therapeutic effect improves, but safety limits may be exceeded
Solution Approach 1:
The patent increases HBsAg yield per cell through optimized expression parameters, which allows achieving the same or higher total antigen dose with fewer cells. This parameter optimization resolves the contradiction by providing more antigen per unit dose, thereby improving therapeutic effect while maintaining safety within established limits
Solution Approach 2:
The patent produces multiple copies of HBsAg within each recombinant cell through high-level expression, creating virus-like particles that present multiple CTL epitopes. This copying approach maximizes the immune stimulatory capacity of each cell dose, improving therapeutic effect without exceeding safety thresholds
3Object-affected harmful factors
If heat inactivation is optimized to enhance safety, then vaccine safety improves, but HBsAg expression and immune response may be reduced
Solution Approach 1:
The patent performs heat inactivation at the optimal time point after HBsAg expression is maximized, ensuring that the full amount of antigen is produced before the inactivation process. This preliminary action sequence ensures both maximum HBsAg quantity and adequate safety through proper inactivation
Solution Approach 2:
The patent optimizes heat inactivation parameters (temperature, time, pH) to achieve complete viral inactivation while minimizing damage to HBsAg structure and immunogenicity. These parameter adjustments ensure safety is enhanced without significant loss of HBsAg amount or immune response capacity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The vaccine significantly enhances immune tolerance reversal, reduces HBV cccDNA levels by over 90% without hepatocyte damage, and improves immune reversion, offering a more effective therapeutic approach for chronic hepatitis B by maximizing HBsAg injection amounts within safe limits and utilizing HBsAg-specific CTL epitopes for targeted immune response.
Implementation Method 1
Gene recombination technology is the core technology of modern biotechnology; also is the mainly technology of the large-scale production of hepatitis B vaccine
Implementation Method 2
H. polymorpha recombinant HBsAg-adr2 hepatitis B vaccine was developed. The yield of HBsAg VLP pure stock solution was 40 mg/L
Implementation Method 3
optimized heat inactivation to enhance immune response and safety
Implementation Method 4
HBsAg with 19 HBsAg-specific CTL epitopes... utilizing HBsAg-specific CTL epitopes for targeted immune response
Data Source
AI summary
A hepatitis B treatment vaccine on the basis of inactivated, whole recombinant Hansenula polymorpha cells expressing HBsAg. The vaccine is the HBsAg expressed in recombinant Hansenula polymorpha cells. 108 cells contain 6-10 μg HBsAg as an antigen; the vaccine contains a total of 16-21 HBsAg-specific CTL epitopes; the vaccine uses optimized inactivated, fully recombinant Hansenula polymorpha cells as an adjuvant.