CXCR4 is expressed in most of synovial T cells from arthritic mice. Mice were induced CIA and CXCR4 expression in the affected joints was analyzed by immunohistochemistry. Cryostat sections of the limb joints from arthritic mice or normal mice were generated and stained with anti-CD3 and anti-CXCR4 antibodies. (a) Representative data among sections from three normal mice and three arthritic mice are shown. Data are summarized in Figure 6c. (b) CXCR4 expression on T cells was analyzed with FACS. As described in Materials and methods, affected limbs from CIA-developed mice were treated with hyaluronidase and collagenase to obtain single-cell suspensions, and stained with anti-CD4 and anti-CXCR4 antibodies. Representative data among three similar experiments are shown.