Fig. 1

The increase of citrullinated proteins in arthritic joints and sera in peptide glucose-6-phosphate isomerase-induced arthritis (pGIA). a Joint sections day 0 and day 14 were immunohistochemically stained with anti-modified citrulline (AMC) antibodies in pGIA or control mice. Citrullinated proteins were detected at day 14 in pGIA mice (indicated by boxed area) but not in control mice. The bottom right image is a magnified view of the boxed area in the joint image at day 14 of pGIA. Original magnification × 100 and × 400 as marked. The experiments were performed on at least three different samples with similar results. b Sera from pGIA and control mice at day 14 subjected to Western blot analysis using AMC antibodies. Citrullinated proteins were detected as a common band at ~ 120 kDa in sera from pGIA mice but not from control mice. Lanes 1–5: control mice; lanes 6–10: pGIA mice. Representative blots are shown at left; data at right are mean ± SEM of band intensity (n = 9). **p < 0.01. c Sera from pGIA mice subjected to Western blot analysis. Citrullinated proteins appeared from day 7, increased at day 14, and decreased at day 28. Lanes 1–3: day 0; lanes 4–7: day 7, lanes 8–11: day 14, lanes 12–15: day 28. Representative blots are shown at left; data at right are mean ± SEM of band intensity (n = 4). *p < 0.05, **p < 0.01