C1s-Deficient CHO Cells for Uncleaved gp120 Production
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Solution Overview
Problem
Mammalian cell lines express pharmaceutically important polypeptides like gp120 are cleaved by proteases, reducing the yield of full-length, uncleaved product due to unknown protease activity, which affects the production of HIV vaccines.
Innovation Solution
Development of C1s protease-deficient cell lines with mutations in the C1s gene, such as CHO cells, to reduce protease activity and enhance the production of uncleaved exogenous polypeptides like gp120, using genetic modifications like deletions or substitutions in the C1s gene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mammalian cell lines are used to express pharmaceutically important polypeptides, then the polypeptides can be produced with proper folding and post-translational modifications, but the yield of full-length uncleaved product is reduced due to protease cleavage
Solution Approach 1:
The harmful C1s protease function is selectively removed from the mammalian cell line through genetic modification (CRISPR/Cas9-mediated knockout), while preserving the cell line's ability to perform proper protein folding and post-translational modifications. This extraction of the specific harmful function allows high-yield production of intact uncleaved polypeptides.
Solution Approach 2:
The protease activity parameter of the cell line is fundamentally changed from active to inactive through genetic modification. By altering the functional state of the C1s protease (from active cleavage function to knockout/null state), the cell line transitions from producing cleaved fragments to producing full-length uncleaved polypeptides with high yield.
2Productivity
If protease activity is reduced in cell lines, then the yield of uncleaved polypeptide increases, but the cell line requires genetic modification
Solution Approach 1:
Rather than adding complex protective systems to prevent cleavage, the solution extracts/removes the harmful C1s protease function through targeted gene knockout. This simplification approach (removing one specific function) achieves the desired outcome without significantly increasing overall system complexity.
Solution Approach 2:
The patent uses CRISPR/Cas9 technology to create a modified copy of the cell line with the C1s gene knocked out. This genetic copying approach allows propagation of the desired trait (lack of C1s protease activity) through stable inheritance in cell divisions, maintaining consistency across cell line generations.
3Reliability
If C1s protease is active in mammalian cells, then the protease can perform its natural function, but it cleaves exogenous polypeptides like gp120 reducing vaccine efficacy
Solution Approach 1:
The patent converts the harmful protease activity into a beneficial absence by knocking out the C1s gene. The cell line's protease deficiency, which would normally be considered a defect, is transformed into a valuable trait that preserves vaccine antigen integrity and enhances immunogenicity. The harmful cleavage function is eliminated while preserving all other cell line functionalities.
Solution Approach 2:
The harmful C1s protease function is selectively removed from the cell line through genetic modification, while preserving the cell line's ability to perform proper protein folding and post-translational modifications. This extraction of the specific harmful function allows high-yield production of intact uncleaved polypeptides.
Data Source
AI summary
The present disclosure reports that a calcium-dependent serine protease, complement component is (C1s) has been identified as a protease responsive for cleavage of exogenous polypeptides expressed in mammalian cell lines such as CHO cells. These CHO cell lines provide for increased yield of antigenically correct, uncleaved exogenous polypeptide as compared to unmodified CHO cells expressing the active C1s protease. C1s-deficient cell lines and methods for use of same for producing exogenous polypeptides, e.g., human immunodeficiency virus (HIV) envelope glycoprotein polypeptides, such as, gp120 or human Factor VIII are provided.