HCV E2 Glycoprotein Constructs for Cell-Surface Antigen Expression
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Solution Overview
Problem
The development of an effective vaccine against Hepatitis C virus (HCV) has been hindered by the virus's genetic diversity, immune evasion tactics, and challenges in producing and scaling the full-length E1-E2 protein complex, which is a major target for neutralizing antibodies.
Innovation Solution
Development of nucleic acid constructs encoding for cell-surface expressible HCV E2 protein with specific mutations (D728A and R730A) to facilitate expression on the cell surface, combined with E1-E2 co-expression, leveraging modern vaccine technologies like mRNA delivery platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the full-length E1-E2 protein complex is used as vaccine antigen, then neutralizing antibody response is improved, but manufacturing complexity and scaling difficulty increase
Solution Approach 1:
The patent segments the full-length E1-E2 protein complex into separate E1 and E2 expression cassettes within the nucleic acid construct. This allows independent optimization of each protein's expression while maintaining their functional association, thereby reducing manufacturing complexity while preserving vaccine efficacy.
Solution Approach 2:
The patent introduces a self-cleaving peptide sequence (P2A or P2B) as an intermediary element between E1 and E2 coding sequences. This mediator enables autonomous cleavage of the polyprotein into functional E1 and E2 proteins during translation, simplifying production by eliminating the need for complex post-translational processing while maintaining protein functionality.
2Ease of manufacture
If conventional inactivated vaccine platform is used, then vaccine development is simplified, but virus titers achieved in cell culture are insufficient
Solution Approach 1:
The patent replaces the mechanical approach of virus inactivation and purification with a molecular biology approach using nucleic acid constructs. The construct encodes E1 and E2 proteins that are expressed and assembled into functional complexes directly in cultured cells, eliminating the need for high-titer virus production and inactivation steps while simplifying the manufacturing process.
3Ease of manufacture
If E1 and E2 are expressed as separate proteins, then manufacturing is simplified, but proper folding and stability of epitopes are compromised
Solution Approach 1:
The patent employs a nested structure where E1 and E2 coding sequences are embedded within a single nucleic acid construct with appropriate spacing and orientation. This nested arrangement ensures coordinated expression and proper stoichiometric ratios, enabling correct protein folding and stable epitope formation while maintaining manufacturing simplicity.
Solution Approach 2:
The self-cleaving peptide acts as an intermediary that facilitates the transition from polyprotein synthesis to individual functional proteins. This mediator ensures proper cleavage timing and location, allowing E1 and E2 to fold correctly into stable structures with intact epitopes while simplifying the manufacturing process compared to co-expression of fully separate proteins.
Data Source
AI summary
The present disclosure provides for novel nucleic acid constructs and methods for expressing HCV E2 protein on a cell surface as an active antigen. The present disclosure provides for a method for evaluation of protein expression. Vaccine formulations, constructs and expression vectors are all within the scope of this disclosure.