CAR-Expressing Immune Cell Characterization via Single-Cell Barcoding
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Solution Overview
Problem
Current methods for characterizing chimeric antigen receptor (CAR) T-cell therapy are limited by the heterogeneity of cell types and functional states in infusion products, with flow cytometry offering incomplete resolution and bulk RNA-seq struggling to link measurements to individual cells and their functional states, particularly in identifying rare cell types.
Innovation Solution
A method involving the partitioning of a reaction mixture into discrete partitions, where immune cells expressing CARs are barcoded with specific sequences, allowing for the enrichment and sequencing of these cells to identify their origin, providing high sensitivity and resolution to characterize infusion products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow cytometry is used to phenotype CAR T-cell populations, then cell population resolution is achieved, but measurement precision is limited due to spectral overlap and operator variability
Solution Approach 1:
The patent replaces flow cytometry (a mechanical/optical sorting system requiring manual gating) with single-cell RNA sequencing combined with CAR-specific bait capture. This substitution eliminates spectral overlap issues and operator variability by using molecular barcoding and high-throughput sequencing instead of fluorescence-based detection and manual analysis.
Solution Approach 2:
The patent changes the detection parameter from fluorescence intensity (prone to spectral overlap) to nucleic acid sequence identity (highly specific). By targeting the unique CAR transgene sequence with complementary bait, the method achieves precise identification of CAR+ cells without the resolution limits of flow cytometry.
2Quantity of substance
If bulk RNA-seq is used to measure CAR T-cell construct presence, then quantification is achieved, but the ability to link measurements to individual cells and their functional states is lost
Solution Approach 1:
The patent segments the bulk RNA-seq approach into single-cell resolution by performing RNA sequencing on individual cells. Each cell's transcriptome is barcoded and sequenced separately, preserving the link between CAR construct presence and the specific cell's functional state while still enabling quantification of CAR abundance.
Solution Approach 2:
The patent introduces cell-specific barcodes as intermediaries between the CAR transcript and the sequencing data. These barcodes allow the measurement of CAR construct abundance while simultaneously tracking which specific cell (and thus which functional state) expresses the CAR, resolving the information loss in bulk analysis.
3Device complexity
If traditional flow cytometric analysis is used to assess immune cells, then the number of markers that can be assessed is limited, but manual gating subjectivity is introduced
Solution Approach 1:
The patent replaces manual flow cytometric gating with automated bioinformatic analysis of single-cell RNA sequencing data. This substitution eliminates operator subjectivity by using algorithm-based cluster identification and differential expression analysis, while simultaneously enabling assessment of thousands of transcriptomic markers beyond the limited panel size of flow cytometry.
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
This approach enables the characterization of CAR-expressing immune cells with a sensitivity threshold of 0.0249%, effectively resolving heterogeneity in infusion products and improving the detection and quantification of CAR incorporation within heterogeneous cell populations.
Implementation Method 1
A bait capable of hybridizing to the scFv encoding portion of the exogenous CAR sequence is used to provide an enriched subset of barcoded nucleic acid molecules
Data Source
AI summary
Provided herein are methods for identification chimeric antigen receptors in immune cells as well as method for identification and characterization of immune cells expressing those chimeric antigen receptors.