Optimization of pH Elution Conditions in Immune Complexome Analysis for Comprehensive Identification of Immune Complex Antigens.

The identification of antigens incorporated into immune complexes (IC-antigens) is important for studying the pathophysiology of immunological diseases. Immune complexome analysis identifies IC-antigens by analyzing ICs collected from biological fluids by IC-capturing beads. In this study, we optimized the method to improve its comprehensiveness while maintaining selectivity for IC-antigens by comparing the number of identified peptides (model IC experiment) or proteins (human pooled serum) eluted from Protein G beads using different pH solutions (pH 2.0 - 11.0).