Soluble Single-Chain MHC Dimers for Peptide-Free T Cell Detection
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Solution Overview
Problem
Existing methods for producing major histocompatibility complex (MHC) class I molecules require peptide presence for stabilization, limiting high-throughput production and peptide exchange processes, and often result in non-specific binding to un-cognate TCRs.
Innovation Solution
Development of cleavable single-chain trimers (cSCTs) that are stabilized through mutations, allowing peptide-free folding and subsequent peptide loading, enabling efficient production of soluble single-chain dimers (sSCDs) for specific T cell detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If peptide-free MHC constructs are used for high-throughput production, then production efficiency is improved, but reagent stability deteriorates
Solution Approach 1:
The patent applies preliminary action by introducing stabilizing mutations (Y84C and A139C) into the HLA protein before peptide loading. These mutations create disulfide bonds that pre-stabilize the MHC structure, allowing the molecule to remain stable in a peptide-free state during high-throughput production and storage, while still enabling subsequent peptide exchange when needed.
2Reliability
If traditional three component refolding is used, then MHC stability is improved, but production complexity increases
Solution Approach 1:
The patent merges the MHC heavy chain and beta-2 microglobulin into a single polypeptide chain through a peptide linker, creating a single-chain MHC construct. This merging eliminates the need for complex three-component refolding processes while maintaining MHC stability, as the single chain can be produced and purified as one unit without requiring assembly of multiple separate components.
3Productivity
If peptide exchange is performed via UV-mediated or temperature-induced methods, then peptide loading efficiency is improved, but non-specific binding increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the peptide linker through specific mutations (Y84C and A139C) that create disulfide bonds. This structural parameter change allows for more controlled and specific peptide exchange, reducing non-specific binding to un-cognate TCRs while maintaining efficient peptide loading capability.
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 cSCT and sSCD approach facilitates rapid, scalable, and cost-effective generation of stable pMHC tetramers with improved specificity for antigen-specific CD8+ T cells, reducing non-specific binding and enhancing TCR discovery.
Implementation Method 1
soluble single-chain dimer (sSCD) proteins produced by cleavage of the cSCT proteins at the unique protease cleavage site
Data Source
AI summary
The present disclosure describes, in part, soluble single-chain dimers (sSCDs) generated from cleavable single-chain trimers (cSCTs), compositions and methods for their production, as well as applications thereof related to characterization of antigen-specific CD8+ T cells and treatments