Figure 2
From: Expression of interleukin-18 receptor in fibroblast-like synoviocytes
IL-18R western blotting and cross-linking experiments. The molecular weight of IL-18Rα in fibroblast-like synoviocytes (FLS) corresponds to ~55 and ~70 kDa (lane 1: positive result in FLS from patients with rheumatoid arthritis [RA]; lane 2: negative result in FLS from patients with osteoarthritis [OA]), and is consistent with a predominant ~100-kDa complex in cross-linking experiments (bound IL-18-GST ~44 kDa) (lane 3). Two smaller bands of linked FLS membrane proteins corresponded to 150–200 kDa and suggest additional, higher-molecular-weight protein complexes containing labeled IL-18, e.g. a complex of the two IL-18R chains. Less intense staining of all cross-linked complexes by competing with unlabeled IL-18 (lane 4) demonstrates the ligand specificity of bound FLS membrane proteins. IL-18R(α) = IL-18 receptor(α).