Binding to native proteins by antipeptide monoclonal antibodies

Area of Science:

• Immunology
• Biochemistry
• Structural Biology

Background:

• Antipeptide monoclonal antibodies (mAbs) are crucial tools in biological research and therapeutics.
• Previous studies suggested these antibodies could bind both synthetic peptides and native antigens.
• Applications include vaccine development, structural characterization, and antigenic determinant identification.

Purpose of the Study:

• To investigate the binding characteristics of antipeptide mAbs to both immobilized and native forms of their target antigens.
• To determine if solid-phase assay results accurately reflect antibody binding to antigens in their native conformation.
• To assess the implications of observed binding discrepancies for interpreting antipeptide antibody data.

Main Methods:

• Solid-phase assays (ELISA) were used to test antibody binding to immobilized antigens.
• Solution-phase assays, including size exclusion High-Performance Liquid Chromatography (HPLC), were employed to assess binding to native antigens.
• Monoclonal antibodies targeting synthetic peptides from cholera toxin, myohemerythrin, and sickle hemoglobin were analyzed.

Main Results:

• All tested antipeptide mAbs bound to their respective immobilized antigens in ELISA.
• None of the antibodies recognized their target antigens in solution-phase assays, indicating a failure to bind the native form.
• A significant discrepancy was observed between solid-phase and solution-phase binding results.

Conclusions:

• Binding of antipeptide mAbs to immobilized antigens or peptides may not reflect binding to the native protein structure.
• Conformational changes or denaturation of antigens on solid-phase matrices can alter epitopes, leading to misleading binding data.
• Re-evaluation of antipeptide mAb binding data in the context of native protein structural characteristics is essential for accurate interpretation.