FIG. 3.

Histopathology in tibiotarsal joints of C57BL/6 and C3^−/− mice induced by infection with B. burgdorferi 5A4. (a and c) Less mononuclear cell inflammation was observed in C57BL/6 mice than in C3^−/− mice. The arrow is pointing to the reactive lining cells of a tendon sheath. T, tendon. (b and d) Mild periosteal remodeling and reactive changes (arrows) seen in C57BL/6 mice compared to C3^−/− mice, as well as new bone (B) and cartilage (C) formation in C3^−/− mice. The arrowhead is pointing to an osteoclast. Hematoxylin and eosin stain was used. Bar = 50 μm.