Flow Cytometry PD-L1 Detection Quantification
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Solution Overview
Problem
Current methods for detecting programmed-death ligand 1 (PD-L1) expression in neoplastic cells are limited in accuracy and reliability, particularly in predicting the responsiveness of cancer to anti-PD-1/PD-L1 immunotherapy, as they often rely on subjective immunohistochemistry assays with variability in staining and semi-quantitative cutoffs.
Innovation Solution
The development of cytometric methods to quantify per cell PD-L1 expression in labeled cell suspensions using flow cytometry or cell cytometry, employing labeled specific binding members and microsphere standards for calibration, allowing for precise detection of cells expressing PD-L1 above a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If immunohistochemistry assays are used to detect PD-L1 expression, then the detection can be performed on tissue samples, but the accuracy and reliability are limited due to subjective staining variability and semi-quantitative cutoffs
Solution Approach 1:
The patent replaces the subjective visual assessment mechanism of immunohistochemistry with an automated flow cytometry system that uses fluorescently labeled antibodies and optical detection to objectively quantify PD-L1 expression on a per-cell basis, eliminating inter-observer variability and semi-quantitative cutoff limitations
Solution Approach 2:
The patent changes the measurement parameter from semi-quantitative staining intensity assessment to precise fluorescent signal quantification, allowing for accurate determination of PD-L1 expression levels including low expression levels that were previously difficult to detect reliably
2Reliability
If flow cytometry methods are used to quantify per cell PD-L1 expression, then the measurement precision and reliability are improved, but the device complexity and assay procedure become more complex
Solution Approach 1:
The patent incorporates preliminary calibration using fluorescent beads with known fluorescence intensities to establish reference standards before analyzing cell samples, ensuring consistent and reliable quantification across different instruments and experiments while simplifying the overall assay procedure through standardized protocols
Solution Approach 2:
The patent uses fluorescently labeled antibodies as intermediaries that specifically bind to PD-L1 on cell surfaces, translating the biological interaction into a measurable fluorescent signal that can be detected and quantified by flow cytometry instruments with high reliability
3Productivity
If semi-quantitative cutoffs are used in immunohistochemistry, then the assay procedure is simpler, but the ability to accurately predict immunotherapy responsiveness is reduced
Solution Approach 1:
The patent replaces the manual semi-quantitative scoring system with automated flow cytometry that provides precise numerical quantification of PD-L1 expression levels on individual cells, enabling accurate identification of cells expressing PD-L1 above clinically relevant thresholds without sacrificing assay throughput
Solution Approach 2:
The patent changes from categorical semi-quantitative scoring to continuous quantitative measurement of fluorescent intensity, allowing for precise determination of PD-L1 expression levels and their relationship to immunotherapy responsiveness while maintaining efficient high-throughput analysis capabilities
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 accurate and reproducible detection of PD-L1 expression, improving the prediction of cancer responsiveness to anti-PD-1/PD-L1 immunotherapy by quantifying PD-L1 levels on a per cell basis, reducing variability and subjectivity, and providing a more reliable assessment of tumor heterogeneity.
Implementation Method 1
contacting the cell with a labeled specific binding member
Implementation Method 2
cytometrically assaying a labeled cell suspension to quantify per cell PD-L1 expression
Data Source
AI summary
Methods are provided for detecting the per cell programmed-death ligand 1 (PD-L1) expression of neoplasia cells. Aspects of the methods include cytometrically assaying a labeled cell suspension to quantify per cell PD-L1 expression to detect whether a neoplastic cell that expresses PD-L1 above a predetermined threshold is present in the neoplasia sample. In addition, kits that find use in practicing the subject methods are also provided.