CRIg-v27 shows improved efficacy in vivo. A, clinical scores for mice treated with CRIg-ECD-Fc (open circles), CRIg-v27-Fc (filled circles), or a negative control Fc fusion protein (triangles) 1 day prior to injection with K/BxN serum. Data represent mean ± S.E. of 7 mice/group. B, scatter plots of clinical scores for individual mice at day 6 following serum transfer. C, hematoxylin and eosin-stained sections of metacarpo-phalangeal joints. Insets in the left panels are magnified in the right panels to highlight mononuclear and neutrophilic inflammatory infiltrates in the joint. D, scatter plots of histological scores at day 6 following serum transfer. *, p < 0.05; **, p < 0.01; ***, p < 0.001. NS, not significant. Scale bars in C, 500 μm (left) or 100 μm (right).