Fig. 6.

CD45 and α-SMA double positive cells are found in the inflammatory infiltrate in CIA. Mice were immunized with either 100 µg CII or PBS in CFA at Day 0 and boosted on Day 21 with CII or PBS in IFA. Joints were collected from CIA animals with a clinical score >3. Haematoxylin and eosin (H & E) staining showing profound inflammatory infiltrate (asterisks) in the CII immunized mice (A, 200× magnification) and no obvious inflammation in control-immunized animals (C, 200× magnification). Immunohistochemistry of plastic embedded joints from CIA or control mice were stained with α-SMA-FITC (green) and CD45-phycoerythrin (red). (A and B) Double positive α-SMA/CD45⁺ fibrocytes from CIA mice [(A), magnification 200×, (B) magnification 400×; smooth muscle, open arrow and infiltrating leucocytes, asterisks] or control-immunized mice (C, magnification 400×) are shown. (D) Isotype control (magnification 200×).