The EZ-Link® Sulfo-NHS-LC Biotin, No-Weigh™ Format kit (Cat#21327, Thermo Scientific, Waltham, MA) and Sulfo-TAG NHS Ester (Sulfo-TAG) kit (Cat# R91AN-2, MSD, Rockville, MD,) were used to label anti-IDs with biotin and Sulfo-tag, respectively. Briefly, the anti-ID proteins in 1X PBS, pH 7.8 without preservative were diluted to < 2 mg/mL followed by a buffer exchange with Amicon-Ultra Centrifugal Filtration column (MWCO 30k, Cat# UFC903008 Millipore Sigma, Burlington, MA). For labeling, biotin or Sulfo-TAG working solution was used at the desired challenge ratio of 1:20. After labeling, a buffer exchange with Amicon-Ultra Centrifugal Filtration column was carried out to remove unbound biotin and Sulfo-TAG. Labeled-protein concentrations were calculated with a Bradford assay.