A comparison between different chemical fractionation methods for immunoglobulin preparation.

Area of Science:

• Biochemistry
• Immunology
• Protein Chemistry

Background:

• Antibody applications in therapeutics and diagnostics are expanding.
• Efficient immunoglobulin (Ig) preparation is crucial for reliable antibody-based assays.
• Optimizing Ig purification methods enhances diagnostic and therapeutic utility.

Purpose of the Study:

• To compare the efficacy of four different chemical preparation methods for immunoglobulin (Ig) purification.
• To determine the optimal method for yielding high-purity and high-recovery polyclonal antibodies against SARS-CoV-2 nucleocapsid (NP).

Main Methods:

• Polyclonal antibodies were generated in rabbits against recombinant SARS-CoV-2 NP.
• Four purification methods were employed: ammonium sulfate (AS), caprylic acid (CA), polyethylene glycol (PEG), and CA/AS.
• Purified Ig solutions were analyzed for purity, recovery, and albumin impurity using SDS-PAGE and ImageJ.
• Antibody binding capacity was assessed via Western blotting and ELISA.

Main Results:

• The CA/AS method resulted in the highest Ig purity and lowest albumin impurity.
• The PEG method yielded the highest Ig recovery rate.
• All methods produced antibodies with comparable NP-binding capabilities in Western blotting and ELISA.

Conclusions:

• The CA/AS method is optimal for achieving high Ig purity.
• The CA method also provides high Ig purity.
• The PEG method is superior for maximizing Ig recovery rates.