Homing in on the specificity of ACPA RhmAb2.101 (A, B), RhmAb2.102 (C, D) and RhmAb2.104 (E, F). ELISA of ACPA dilution series on various citrullinated and non-citrullinated histone proteins (A, C, E) and citrulline-containing histone-derived peptides (B, D, F). All ACPA react strongly with PAD2-deiminated human histone-2A (H2A/p2; A, C, E) and to a somewhat lesser extent with PAD2-deiminated human histone-4 (H4/p2; A, C, E). As with their specific citrulline-dependent reactivity towards various histone isoforms, ACPA showed selective reactivity towards citrulline-containing peptide -1*, -4, -6, and -7 (B, D, F). CFC1 was used as a positive, and CFC0 as a negative control in ELISA experiments.
Figure 7: Homing in on the anti-histone specificity of ACPA.