Fig. 4

Incubation of aggrecan with synovium + joint capsule (SJC). Bovine aggrecan A1D1 fraction (purified from cartilage) was incubated for 1 h or 24 h with or without bovine SJC in the presence or absence of externally added tumor necrosis factor-α (TNF-α) (see Methods section of main text). After incubation, the SJC was removed and aggrecan samples were deglycosylated and run on 3–8% Tris-acetate SDS gels, and immunobands were visualized by Western blotting using FFGV (a), ARGS (b), and G3 (c) aggrecan antibodies. Bovine aggrecan fragments discussed in the text are shown on the left side in each panel with the molecular mass indicated in kilodaltons. Representative Western blot images from full-size blotted gels are shown. Sulfated glycosaminoglycan (sGAG) was loaded at 2–3 μg/lane. *Bands considered to be false-positive immunobands because they could not be blocked by their corresponding immunopeptides