CD155 Detection via D3G7H Antibody Epitope Specificity
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Solution Overview
Problem
There is a lack of reliable methods for unambiguous, semi-quantitative analysis of CD155 expression in tumor tissue samples, which is crucial for assessing the suitability of PVSRIPO oncolytic immunotherapy in glioblastoma and other cancers, due to the limited availability of suitable antibodies for immunohistochemistry.
Innovation Solution
A method using a primary antibody that specifically binds to an epitope on CD155, specifically residues 164-182, such as the rabbit monoclonal antibody D3G7H, is employed for assaying CD155 expression in tumor tissue samples, forming a robust antigen-antibody complex for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antibodies are used for CD155 detection, then broad CD155 upregulation in cancer histotypes can be observed, but the antibodies are not suitable for IHC in normal tissues and lack reliability
Solution Approach 1:
The patent changes the critical parameter of antibody selection by identifying and using a specific antibody (D3G7H) that recognizes a unique epitope (residues 164-182) on CD155. This parameter change from conventional antibodies to a specifically validated antibody resolves the contradiction by providing both reliability for detecting cancer-associated CD155 upregulation and precision for distinguishing it from normal tissue expression levels.
2Measurement precision
If IHC assays are performed without validated antibodies, then broad CD155 upregulation can be detected, but unambiguous semi-quantitative analysis cannot be achieved
Solution Approach 1:
The patent applies preliminary action by performing comprehensive validation of the D3G7H antibody across multiple normal human tissues before using it for cancer tissue analysis. This preliminary validation step establishes the antibody's specificity and enables subsequent semi-quantitative analysis, resolving the contradiction by investing complexity upfront to achieve precision later.
Solution Approach 2:
The patent uses the D3G7H antibody as an intermediary tool that bridges the gap between detecting CD155 expression and achieving semi-quantitative analysis. This specifically validated antibody serves as a reliable mediator that translates tissue staining patterns into quantifiable expression levels, enabling precision measurement without requiring complex alternative methodologies.
3Reliability
If CD155 expression is assessed in tumor samples, then suitability for PVSRIPO immunotherapy can be determined, but lack of reliable assays prevents accurate identification of CD155 levels
Solution Approach 1:
The patent extracts the critical element needed for reliable CD155 detection—the D3G7H antibody with its specifically validated epitope recognition (residues 164-182)—from the broader context of available antibodies. By isolating and focusing on this single validated reagent, the patent simplifies the assay implementation while ensuring accuracy, resolving the contradiction between reliability and ease of manufacture.
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 provides a reliable and specific method for detecting CD155 expression in tumor tissues, enabling pre-clinical assessments of PVSRIPO oncolytic immunotherapy suitability in various cancers by ensuring accurate identification of CD155 levels, which correlates with viral susceptibility and therapeutic effectiveness.
Implementation Method 1
A tumor tissue sample is contacted under conditions suitable for antibody-antigen binding with a primary antibody that specifically binds to an epitope on CD155. The epitope is in residues 164-182 of CD155.
Data Source
AI summary
A reliable assay to specifically detect CD155 in tissue sections has widespread use because CD155 is expressed widely among tumor types. Additionally, detected expression of CD 155 in glioblastoma cells is at levels commensurate with susceptibility to PVSRIPO (a poliovirus construct) infection and killing. An anti-CD155 antibody can achieve mono-specific detection of CD155 in immunoblots of tumor homogenates and immunohistochemistry of tumor formalin fixed, paraffin embedded sections. The assay can be used to determine appropriate use of PVSRIPO in oncolytic immunotherapy against cancers.