Figure 2.

Antibody–ODN labeling and purification. (A) Protein G (pG) was conjugated to a 20 nt 3′-maleimide-functionalized ODN. Human IgG1 (hIgG1) was incubated with varying molar equivalents of unpurified pG-ODN, and the labeling efficiency was analyzed and compared with purified pG-ODN under reducing SDS-PAGE conditions. Without pG-ODN purification, ∼20% of the heavy chains were coupled to pG instead of pG-ODN. (B) Reducing SDS-PAGE analysis of various IgG subclasses coupled to 10 equiv pG-ODN and a (C) hIgG1 antibody coupled to pG-ODN in the presence and absence of 0.07% (w/v) bovine serum albumin (BSA). (D) Excess of pG-ODN was removed using protein-L-functionalized magnetic beads covalently coupled to a scavenger antibody via a PEGylated bis(sulfosuccinimiyl)suberate linker (BS(PEG)₅). The average recovery (green) and contamination (red) of the magnetic beads (MBs) were compared to ultrafiltration (UF). Error bars represent SD (n = 3).