Identification and characterization of shark VNARs targeting the Helicobacter pylori adhesin HpaA
Yanchun Gao1,2, Ruihong Wang3, Lin Liu2
1College of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, P.R. China.
Insights
Novel shark-derived antibodies targeting Helicobacter pylori adhesin A (HpaA) show promise for new treatments and diagnostics. These variable domain of immunoglobulin new antigen receptor (VNAR) antibodies offer a stable alternative to current H. pylori therapies.
Area of Science:
- Immunology
- Microbiology
- Biotechnology
Background:
- Helicobacter pylori (H. pylori) infection causes gastrointestinal diseases, with antibiotic resistance limiting current treatments.
- H. pylori adhesin A (HpaA) is crucial for bacterial adhesion to the gastric mucosa.
- Antibodies targeting HpaA represent a potential therapeutic strategy.
Purpose of the Study:
- To isolate and characterize variable domain of immunoglobulin new antigen receptor (VNAR) antibodies against H. pylori HpaA.
- To develop enhanced bivalent VNAR constructs for improved binding affinity and stability.
- To establish a diagnostic assay for H. pylori HpaA detection.
Main Methods:
- Isolation of VNARs against HpaA using a shark VNAR phage display library.
- Characterization of VNAR binding to recombinant and native HpaA.
- Construction and evaluation of homodimeric bivalent VNARs (biNb-2A2, biNb-3D6).
- Assessment of VNAR stability under gastrointestinal pH conditions.
- Development of a sandwich ELISA assay for HpaA quantification.
Main Results:
- VNARs 2A2 and 3D6 demonstrated high binding affinity to HpaA, recognizing distinct epitopes.
- Bivalent VNARs (biNb-2A2, biNb-3D6) exhibited enhanced binding affinity and stability at low pH.
- A sandwich ELISA assay was successfully developed using biNb-2A2 and biNb-3D6 for HpaA detection.
Conclusions:
- Shark-derived VNARs are effective binders of H. pylori HpaA.
- Engineered bivalent VNARs offer improved affinity and stability for potential therapeutic and diagnostic applications.
- This study provides a foundation for novel H. pylori infection management strategies.
Abstract:
Helicobacter pylori (H. pylori) is recognized as a pathogen associated with several gastrointestinal diseases. The current treatments exhibit numerous drawbacks, including antibiotic resistance. H. pylori can adhere to and colonize the gastric mucosa through H. pylori adhesin A (HpaA), and antibodies against HpaA may be an effective therapeutic approach. The variable domain of immunoglobulin new antigen receptor (VNAR) is a novel type of single-domain antibody with a small size, good stability, and easy manufacturability. This study isolated VNARs against HpaA from an immune shark VNAR phage display library. The VNARs can bind both recombinant and native HpaA proteins. The VNARs, 2A2 and 3D6, showed high binding affinities to HpaA with different epitopes. Furthermore, homodimeric bivalent VNARs, biNb-2A2 and biNb-3D6, were constructed to enhance the binding affinity. The biNb-2A2 and biNb-3D6 had excellent stability at gastrointestinal pH conditions. Finally, a sandwich ELISA assay was developed to quantify the HpaA protein using BiNb-2A2 as the capture antibody and BiNb-3D6 as the detection antibody. This study provides a potential foundation for novel alternative approaches to treatment or diagnostics applications of H. pylori infection.
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