Fig. 6

Conversion of mAlb-CTLA4Ig to mCTLA4Ig in the joints of mice that developed collagen-induced arthritis (CIA). A mAlb-CTLA4Ig was added to DMEM, CIA synovial fluid (CIA-SF) lavage, or normal synovial fluid (normal-SF) lavage. Conversion of mAlb-CTLA4Ig (~ 130 kDa under reducing condition) to mCTLA4Ig (red arrow, ~ 55 kDa under reducing condition) was detected by western blot using an anti-mouse CTLA4 antibody. B mAlb-CTLA4Ig was injected into CIA mice or normal mice for 24 h. Paws were harvested, homogenized, and analyzed by western blotting using an anti-mouse CTLA4 antibody. Positions of paws are indicated by capitalized letters R and L. Numbers in parentheses indicate the disease scores of the paws. C Synovium-infiltrating cells were isolated from CIA mice and analyzed for Gr-1 and CD80 expression by flow cytometry. Approximately 1/3 of the GR-1⁺ cells in the synovial fluid and ~ 1/5 of the GR-1⁺ cells in the synovial membranes expressed CD80, whereas blood GR-1⁺ cells did not express CD80. D Synovium-infiltrating cells were isolated from CIA mice and tested for mCTLA4Ig binding by flow cytometry. E Effect of in vitro mCTLA4Ig treatments on TNF-α secretion by joint-infiltrating cells stimulated with precoated collagen-antibody immunocomplexes