Serum samples of patients with rheumatoid arthritis contain a specific autoantibody to “denatured” aldolase A in the osteoblast-like cell line, MG-63
- Fumio Ukajia,b,
- Isao Kitajimaa,
- Toshikazu Kuboc,
- Choji Shimizuc,
- Toshihiro Nakajimad,
- Ikuro Maruyamaa
- aDepartment of Laboratory and Molecular Medicine, Kagoshima University, School of Medicine, Kagoshima, Japan, bTsukuba Research Laboratories, Tokuyama Corporation, Tsukuba, Japan, cDepartment of Orthopaedic Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan, dInstitute of Applied Biochemistry, University of Tsukuba, Tsukuba, Japan
- Dr I Kitajima, Department of Laboratory and Molecular Medicine, Faculty of Medicine, Kagoshima University, 8–35–1 Sakuragaoka, Kagoshima City, Kagoshima 890–8520, Japan.
- Accepted 23 December 1998
Abstract
OBJECTIVE To identify rheumatoid arthritis (RA) specific autoantibody and its antigen in the human osteoblast-like cell line, MG-63.
METHODS MG-63 cell extract was subjected to western blotting by using RA and normal serum samples as probes. The autoantigen was purified and its N-terminal sequence was determined by automated Edman degradation. The reactivity of denatured aldolase A was evaluated by immunoblotting. Screening by enzyme linked immunosorbent assay (ELISA) using the autoantibody was performed.
RESULTS 40 kDa protein was found only in the RA serum samples and it was identified as aldolase A. A polyclonal antibody for rabbit muscle aldolase A bound to the 40 kDa protein and reacted in preference with the denatured enzyme. Using ELISA for denatured rabbit aldolase A, the autoantibody was found in approximately 10% of RA patients, whereas it was not found in the other arthropathy and healthy adults.
CONCLUSION This 40 kDa anti-aldolase A autoantibody, which was identified only in serum samples of RA patients with severe bone erosion, could be related to a certain event that induces RA specific joint destructions.
