Caged Hapten Proximity Assay for FFPE Tissue
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Solution Overview
Problem
Current methods for detecting protein-protein interactions in formalin-fixed, paraffin-embedded tissues are not reliable or cost-effective, particularly due to the high expense and limited compatibility with automated systems of existing proximity ligation assays using DNA ligases and Phi29 DNA polymerase.
Innovation Solution
A method involving caged haptens and their conjugates with specific antibodies, where an unmasking enzyme reacts with an enzyme substrate to reveal the hapten, allowing for detection of proximal targets using chromogenic or fluorescent substrates, enabling efficient and cost-effective detection of protein interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proximity ligation assay uses DNA ligases and Phi29 DNA polymerase, then protein-protein interactions can be detected in FFPE tissues, but the cost increases significantly and automation compatibility is limited
Solution Approach 1:
The patent replaces expensive, complex enzymes (DNA ligases and Phi29 DNA polymerase) with inexpensive, commercially available antibodies conjugated to caged haptens. The caged hapten system uses simple chemical substrates that can be detected by standard chromogenic or fluorescent methods, eliminating the need for costly proprietary enzyme systems while maintaining detection reliability in FFPE tissues.
Solution Approach 2:
The invention extracts and removes the expensive DNA-based enzymatic components from the proximity ligation assay, retaining only the essential function of detecting proximal protein targets. By using caged haptens that can be unmasked by proteolytic cleavage near the target protein, the system eliminates the need for DNA ligases and Phi29 polymerase, achieving cost reduction without sacrificing detection capability.
2Reliability
If proximity ligation assay uses DNA ligases and Phi29 DNA polymerase, then protein-protein interactions can be detected in FFPE tissues, but compatibility with automated systems is reduced
Solution Approach 1:
The patent replaces expensive, complex enzymes (DNA ligases and Phi29 DNA polymerase) with inexpensive, commercially available antibodies conjugated to caged haptens. The caged hapten system uses simple chemical substrates that can be detected by standard chromogenic or fluorescent methods, eliminating the need for costly proprietary enzyme systems while maintaining detection reliability in FFPE tissues.
Solution Approach 2:
The invention substitutes the complex biochemical machinery of DNA ligases and Phi29 DNA polymerase with a simpler antibody-based recognition system combined with caged hapten chemistry. This replacement uses standard immunohistochemistry principles that are already well-established in automated pathology systems, thereby improving compatibility with automated processing while maintaining the ability to detect protein-protein interactions.
3Ease of manufacture
If alternative technologies are used to probe molecular interactions on FFPE tissue, then cost is reduced, but reliability and effectiveness under practical use are not achieved
Solution Approach 1:
The patent segments the detection system into distinct functional components: (1) an antibody conjugated to a caged hapten that binds the first target protein, (2) a second antibody that binds the second target protein and brings it into proximity with the caged hapten, and (3) a detection system that recognizes the unmasked hapten. This segmentation allows each component to be optimized independently, ensuring both cost-effectiveness and reliability.
Solution Approach 2:
The caged hapten acts as an intermediary molecule that bridges the two target proteins. When the first antibody binds its target and the second antibody binds its target in proximity, the caged hapten on the first antibody is brought close to the second antibody, enabling detection through hapten-unmasking. This intermediary approach ensures reliable detection of protein-protein interactions while using cost-effective reagents.
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 allows for reliable and cost-effective detection of protein-protein interactions in formalin-fixed, paraffin-embedded tissues, enhancing diagnostic capabilities and reducing the need for expensive enzymes, thereby improving the efficiency and applicability of protein interaction analysis.
Implementation Method 1
an unmasking enzyme of the second antibody-conjugated protein binding entity is capable of reacting with an enzyme substrate portion of the caged hapten to unmask the hapten
Implementation Method 2
a first antibody-conjugated protein binding entity specific for a first target in a sample is provided, wherein the first antibody-conjugated protein binding entity comprises a caged hapten
Implementation Method 3
allowing for detection of proximal targets using chromogenic or fluorescent substrates
Implementation Method 4
allowing for detection of proximal targets using chromogenic or fluorescent substrates
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
Disclosed herein are caged haptens and caged hapten-antibody conjugates useful for enabling the detection of targets located proximally to each other in a sample.