Bridging ELISA

Creative Diagnostics specializes in providing Bridging ELISA (Bridge Enzyme-Linked Immunosorbent Assay) solutions, offering reliable detection tools for quality control, pharmacokinetic studies, and immunological analysis in the biopharmaceutical field. Bridging ELISA is a highly specific sandwich immunoassay technique particularly suitable for detecting antigens with multiple identical binding sites. It plays a critical role in biopharmaceutical development, clinical trial support, and quality assessment.

Technical Principle

Bridging ELISA is an important subtype of sandwich ELISA, which utilizes the characteristic of an antigen forming a "bridging" complex with two antibodies for detection. The core mechanism is as follows: when an antigen molecule possesses two or more identical binding sites, a capture antibody binds to the antigen, while the same antigen can simultaneously bind to another detection antibody, thereby forming a stable ternary complex structure. This design leverages the specificity of antigen-antibody interactions, offering higher detection accuracy compared to other types of ELISA.

Figure 1. General scheme in a bridging ELISA for ADA detection
(Source: Suh K, et al. 2022)

A typical Bridging ELISA procedure includes the following key steps:

1. Solid Phase Coating: Immobilize specific capture antibodies onto a 96-well plate to create a solid-phase surface.
2. Sample Incubation: Add the sample containing the target antigen, allowing the antigen to bind to the immobilized capture antibodies.
3. Secondary Antibody Binding: Introduce an enzyme-labeled detection antibody to form a complete bridging complex.
4. Chromogenic Reaction: Add an enzyme substrate, which produces a measurable signal through enzymatic catalysis.
5. Result Interpretation: Measure the optical density (OD value) using a microplate reader and quantify the results by comparing them to a standard curve.

Application

• Therapeutic Antibody Detection
  The most common application of Bridging ELISA is detecting the serum concentration of therapeutic antibodies (Drug Antibodies, DA). In biopharmaceutical development, this technique enables the accurate measurement of concentration levels of monoclonal antibody-based therapeutics in patients, providing quantitative data support for pharmacokinetic studies, dose optimization, and efficacy evaluation.
• Anti-Drug Antibody Detection
  When the body mounts an immune response against exogenous antibody drugs, it may produce Anti-Drug Antibodies (ADA). Bridging ELISA can specifically detect these immune response-generated antibodies, which is crucial for assessing the immunogenicity of biopharmaceuticals. This detection is highly significant for understanding drug safety and clinical effectiveness.
• Bispecific Antibody Characterization
  For bispecific antibodies (BsAbs) capable of binding two different targets, Bridging ELISA can simultaneously verify the antibody's binding capability to both targets. This "dual-target bridging" technique is a key characterization tool in the development of bispecific antibody drugs, confirming whether the antibody possesses the intended dual-target recognition function.