Fig. 1

Histology of knee joint inflammation. H&E-stained knee joint sections of immmunized (a, b) and non-immunized (c, d) mice were analyzed 60–70 days after i.a. injection of mBSA (a, c) or PBS (b, d). Arrows indicate mononuclear cells infiltrating the synovial membrane and fibrosis, black bar 250 μm. e (left panel), the magnitude of joint inflammation was determined in a 3 parameter scoring system for synovial hyperplasia (1–3 points), infiltration of the synovial membrane by mononuclear cells (1–3 points), and fibrosis (1–3 points). e (right panel), the joint destruction score was determined by adding up pannus formation (1–3 points) and cartilage and bone erosion (1–3 points). Statistical analysis was performed using the Mann-Whitney U test to compare the scores between mBSA-injected knee joints of immunized (N = 11) and non-immunized (N = 9) animals (*P < 0.05); the Wilcoxon signed rank test was used to compare the scores between mBSA- (ipsilateral) and PBS-injected (contralateral) knee joints