Delineating monoclonal antibody specificity by mass spectrometry

Area of Science:

• Biochemistry
• Immunology
• Analytical Chemistry

Background:

• Generating monoclonal antibodies (mAbs) against complex biological samples is challenging due to difficulties in characterizing their specificity.
• Existing methods for antibody characterization often limit the analytical potential of newly generated mAbs.

Purpose of the Study:

• To develop a strategy for producing monoclonal antibodies (mAbs) from complex biological fluids.
• To establish and optimize immuno-affinity techniques coupled with mass spectrometry (immuno-MS) for robust mAb characterization.
• To demonstrate the utility of these protocols for identifying antigens, including low-abundance ones, and facilitating proteome analysis.

Main Methods:

• Mice were immunized with fractionated seminal plasma to produce mAbs.
• Four different immuno-MS protocols were established using various solid supports (microtiter plates, agarose beads, magnetic beads, pipette tips).
• A well-characterized anti-KLK3 (PSA) mAb was used to evaluate protocol robustness, reproducibility, and establish antigen characterization criteria.

Main Results:

• All tested immunoassay configurations proved capable of antibody characterization.
• The developed immuno-MS protocols successfully identified low-abundance antigens (e.g., ribonuclease T2) with the same efficiency as high-abundance antigens.
• The strategy allows for the production of mAbs from complex biological samples and their efficient characterization.

Conclusions:

• Complex biological fluids can be effectively used for monoclonal antibody production, aiding in the discovery of novel disease biomarkers.
• Established immuno-MS protocols provide reliable and reproducible methods for identifying antibody specificity.
• This approach facilitates ultra-sensitive analysis of biomolecules in their native form and enhances proteome analysis capabilities.