Purification and characterization of Ki antigen and detection of anti-Ki antibody by enzyme-linked immunosorbent assay in patients with systemic lupus erythematosus.
Ki antigen from rabbit thymus extract was purified by ammonium sulfate precipitation, anti-Ki affinity chromatography, and high pressure liquid chromatography gel filtration. The purified Ki antigen gave a single polypeptide with an MW of 32,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it specifically reacted with anti-Ki antibody by immunoblotting. The isoelectric point of the Ki antigen was found by isoelectric focusing to be 4.3. An enzyme-linked immunosorbent assay using the purified Ki antigen was established, and the clinical significance of the anti-Ki antibody in systemic lupus erythematosus (SLE) was studied. Thirty of 140 patients with SLE (21.4%) had anti-Ki antibody by enzyme-linked immunosorbent assay, whereas 11 (7.9%) were positive by double immunodiffusion. Analysis of clinical and serologic data on patients with SLE suggested a higher prevalence of central nervous system involvement in patients with anti-Ki antibody.
Sakamoto
M
M
Department of Internal Medicine, Juntendo University School of Medicine, Tokyo, Japan.
Takasaki
Y
Y
Yamanaka
K
K
Kodama
A
A
Hashimoto
H
H
Hirose
S
S
D000906:Antibodies / Q000032:analysis*; D003882:Dermatomyositis / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007525:Isoelectric Focusing; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D008947:Mixed Connective Tissue Disease / Q000276:immunology; D009220:Myositis / Q000276:immunology; D009687:Nuclear Proteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D010455:Peptides / Q000032:analysis
D000906:Antibodies; D009687:Nuclear Proteins; D010455:Peptides