Examples of histological evaluation of tumor necrosis factor-alpha transgenic (TTg) mice immunized with tumor necrosis factor kinoid (TNF-K) or phosphate-buffered saline (PBS). Histological sections (magnification × 40) of the knees of TNF-K- or PBS-treated mice were prepared (see Materials and methods) and colored with hematoxylin and eosin (a, b) to observe synovial inflammation or with safranin-O (c, d) to observe cartilage degradation. For the histological sections of TTg mice immunized with TNF-K, inflammation (a) and destruction (c) were scored at 0; for the control group, inflammation (b) and destruction (d) were scored at 2. Black arrows show thickness and inflammatory infiltration of synovial membrane in (b) and a normal appearance in (a). White arrows show depletion of proteoglycan (a marker for cartilage destruction) in (d) and a normal full-red staining in (c).