Takizawa Y, Suzuki A, Sawada T, Ohsaka M, Inoue T, Yamada R, Yamamoto K
Department of Allergy and Rheumatology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, 1138655 Japan.
Ann Rheum Dis. 2006 Aug;65(8):1013-20. doi: 10.1136/ard.2005.044743. Epub 2006 Jan 31.
Anti-citrullinated protein antibodies (ACPA) are specifically and frequently detected in sera of patients with rheumatoid arthritis (RA). Citrullinated fibrin or fibrinogen is a candidate autoantigen of such antibodies.
To investigate the presence of citrullinated fibrinogen (cFBG) in the plasma or synovial fluid of patients with RA and control patients, and to determine cFBG levels and their relationship with serum markers for RA if it is present.
A sandwich enzyme linked immunosorbent assay (ELISA) to measure cFBG was established using monoclonal antibodies cF16.1 and cF252.1, generated by immunising mice with R16Cit and R252Cit, the fibrinogen Aalpha chain derived sequences with citrulline at position 16 and 252, respectively, and the presence of cFBG was further investigated with immunoprecipitation-western blotting.
Positive signals were detected in 11/15 RA synovial fluids (RASFs), but not in osteoarthritis synovial fluids or RA plasma with sandwich ELISA for cFBG using cF16.1 and an anti-modified citrulline (AMC) antibody. The presence of cFBG in RASFs was confirmed by immunoprecipitation-western blotting. Furthermore, most RA sera strongly reacted against R16Cit. No relationship was seen between RASF cFBG levels and C reactive protein or anti-cyclic citrullinated peptide antibody levels of the paired sera.
cFBG is detected as a soluble citrullinated autoantigen in RASFs and may therefore be a genuine candidate antigen for ACPA in patients with RA.
抗瓜氨酸化蛋白抗体（ACPA）在类风湿关节炎（RA）患者血清中被特异性且频繁地检测到。瓜氨酸化的纤维蛋白或纤维蛋白原是这类抗体的候选自身抗原。
研究RA患者及对照患者血浆或滑液中瓜氨酸化纤维蛋白原（cFBG）的存在情况，若存在则测定cFBG水平及其与RA血清标志物的关系。
使用单克隆抗体cF16.1和cF252.1建立夹心酶联免疫吸附测定（ELISA）法来检测cFBG，这两种抗体是通过分别用R16Cit和R252Cit免疫小鼠产生的，R16Cit和R252Cit分别是纤维蛋白原Aα链在第16和252位带有瓜氨酸的序列，并用免疫沉淀-蛋白质印迹法进一步研究cFBG的存在情况。
使用cF16.1和抗瓜氨酸化修饰（AMC）抗体的夹心ELISA法在11/15例RA滑液（RASF）中检测到阳性信号，但在骨关节炎滑液或RA血浆中未检测到。通过免疫沉淀-蛋白质印迹法证实了RASF中存在cFBG。此外，大多数RA血清与R16Cit强烈反应。配对血清的RASF cFBG水平与C反应蛋白或抗环瓜氨酸肽抗体水平之间无相关性。
在RASF中检测到cFBG作为可溶性瓜氨酸化自身抗原，因此可能是RA患者中ACPA的真正候选抗原。
