HEK293 cells were lysed and citrullinated with human PAD4. Citrullinated cell lysates were subsequently immunoprecipitated with ACPA RhmAb2.101 or tACPA RhmAb2.102 coupled to Protein A Sepharose beads, or with Protein A Sepharose beads only. Beads were washed, and bound proteins were eluted and subjected to SDS-PAGE (15%), followed by protein staining using Coomassie Brilliant Blue.
