Monoclonal Antibody 3D9 for Specific NET Detection
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Solution Overview
Problem
Current methods for detecting neutrophil extracellular traps (NETs) are unreliable and lack specificity, hindering research and diagnosis due to weak signals and non-specific markers, particularly in complex tissues and mixed samples.
Innovation Solution
Development of a monoclonal antibody 3D9 that specifically binds to the C-terminal fragment of cleaved histone H3 at site L48R49, enabling distinct detection and quantification of NETs by recognizing a novel histone cleavage site unique to NET formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If anti-histone antibodies are used to detect NETs, then strong staining signal is obtained, but nuclei of naïve neutrophils are also stained causing loss of specificity
Solution Approach 1:
The invention targets a specific local modification (cleavage at L48R49 site) rather than the entire histone molecule. The monoclonal antibody 3D9 is designed to recognize only the C-terminal fragment of cleaved histone H3, creating local specificity at the cleavage site while maintaining strong binding affinity, thus distinguishing NETs from naïve neutrophil nuclei.
Solution Approach 2:
The histone H3 molecule is segmented by proteolytic cleavage at the L48R49 site, separating the N-terminal and C-terminal fragments. The invention exploits this segmentation by developing an antibody that specifically binds to the C-terminal fragment, which is only present in cleaved histones within NETs, not in intact histones of naïve cells.
2Reliability
If anti-neutrophil elastase antibodies are used to detect NETs, then specific NET labeling is achieved, but the staining signal is significantly dimmer compared to granules of resting cells
Solution Approach 1:
The invention changes the detection parameter from targeting neutrophil elastase (which has variable concentration and weak signal in NETs) to targeting the C-terminal fragment of cleaved histone H3. This parameter change exploits a binary state (cleaved vs. intact) that produces strong, consistent staining signals while maintaining high specificity for NETs.
3Adaptability or versatility
If current NET detection methods using multiple antibodies are used, then comprehensive NET characterization is achieved, but results between different laboratories are difficult to compare due to complex sample preparation and image analysis
Solution Approach 1:
The monoclonal antibody 3D9 serves multiple functions: it specifically detects NETs, provides strong staining signals for clear visualization, and enables consistent quantification across different laboratories. By targeting a universal marker (cleaved histone H3 C-terminal fragment) that is consistently present in all NETs regardless of formation pathway, the antibody achieves both comprehensiveness and reproducibility.
Data Source
AI summary
The present invention relates to a monoclonal antibody 3D9 specifically binding a C-terminal fragment of cleaved histone H3 in NETs that can be used to specifically detect NETs distinguishing them from chromatin of different origin. The invention also provides a method for in vitro detection of neutrophil extracellular traps in isolated biological samples as well as a method for assessing a disease condition associated with NET formation. The present invention also relates to an isolated fragment of human histone H3 cleaved at site L48R49, and to the use of cleavage site L48R49 for specific detection of human neutrophil extracellular traps. The present invention also relates to recombinant nucleic acid sequences encoding said polypeptides, and host cells comprising the same.