Immunization of citBiP induced anti-citrullinated protein/peptide antibodies in mice. Immunized citBiP was prepared in the same way as the one shown in Figure 1B. A. Serum levels of anti-CCP antibodies in control, complete Freund's adjuvant (CFA)-immunized, BiP+CFA-immunized, and citBiP+CFA-immunized mice. B. Serum levels of anti-fibrinogen and anti-citrullinated fibrinogen antibodies in control and immunized mice. **: P < 0.01. C. Immunofluorescence assay of mouse serum to the rat esophageal horny layer (arrows). The horizontal lines indicate medians. P-values were calculated by Mann-Whitney U test.