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Expression of autocrine motility-like factor in rheumatoid synovial fluid
H Watanabe1, K Takeuchi, M Chigira
1Department of Orthopedic Surgery, Gunma University School of Medicine, Japan.
Objective:
To examine whether a cytokine, autocrine motility factor (AMF), plays a role in rheumatoid arthritis (RA).
Methods:
We investigated the chemokinetic activity of synovial fluids (SF) obtained from patients using a unique protein-free culture fibrosarcoma Gc-4 PF, the motility of which is specifically dependent on the cytokine.
Results:
Treatment of the cells with the SF stimulated their phagokinetic motility by 1.4, 1.8, and 2.1-fold at protein concentrations of 100, 250 and 500 micrograms/ml, respectively. This dose dependent response was observed in all 3 patients with classical or definite RA. In contrast with Gc-4 PF cells, the SF did not stimulate the motility of Gc-4 SD cells that have little response to AMF. The ability of this chemokinetic activity to block binding of the monoclonal antibody to the receptor for AMF was demonstrated on immunoblots.
Conclusion:
Based on these results, it is suggested that the motile activity may be AMF. The possible role of the cytokine in the pathogenesis of RA is discussed.