Non-specific binding in solid phase immunoassays for autoantibodies correlates with inflammation markers

Area of Science:

• Immunology
• Biochemistry
• Medical Diagnostics

Background:

• Enzyme-linked immunosorbent assay (ELISA) is crucial for detecting human autoantibodies.
• ELISA specificity can be compromised by non-specific immunoglobulin binding to plastic surfaces.
• Understanding non-specific binding mechanisms is vital for accurate autoantibody detection.

Purpose of the Study:

• To investigate the mechanisms of non-specific immunoglobulin deposition in ELISA.
• To identify factors contributing to false positive autoantibody results.
• To propose strategies for reducing non-specific binding in diagnostic assays.

Main Methods:

• Analysis of non-specific binding in autoantigen-coated and non-coated ELISA wells.
• Quantification of immunoglobulin G (IgG) and inflammatory mediators in sera.
• Experimental induction of non-specific binding by altering IgG concentration and temperature.

Main Results:

• 4-32% of sera exhibited high non-specific binding, varying with assay conditions and serum properties.
• Sera with high non-specific binding showed increased IgG and inflammatory mediators.
• Non-specific binding was inducible by elevated IgG concentrations and incubation at 40°C.

Conclusions:

• Non-specific binding in ELISA is linked to increased IgG levels and inflammatory conditions.
• The phenomenon suggests that high immunoglobulin concentrations and elevated temperatures during inflammation can promote non-specific binding.
• Non-specific binding can serve as an indicator of elevated IgG and systemic inflammation.