Singh I, Francis G E
J Clin Pathol. 1978 Oct;31(10):963-73. doi: 10.1136/jcp.31.10.963.
A simple routine method is described for the quantitation of antiglobulin (rheumatoid factor) in human serum irrespective of its immunoglobulin class. Papain Fc fragment of human IgG is labelled with fluorescein isothiocyanate and incubated with the serum. Bound Fc is separated from free Fc by precipitation with polyethylene glycol and measured by the fluorescence of the precipitate. Results are expressed as a percentage of the binding obtained with a normal pool serum. About 60% of seronegative rheumatoid sera and 96% of seropositive rheumatoid sera gave results more than 2SD above the mean value for normal sera. Only 17% of osteoarthritis sera gave positive results by the same criterion. A relationship is also deduced to show that if the test is carried out at a number of Fc concentrations a double reciprocal plot of bound Fc against free Fc enables both the total antiglobulin and the ratio of binding constants of antiglobulin for Fc and for IgG to be calculated. This ratio is approximately unity. Under the standard conditions the results correspond to a measurement of approximately 30% of the total antiglobulins present.
本文描述了一种简单的常规方法，用于定量检测人血清中的抗球蛋白（类风湿因子），而无需考虑其免疫球蛋白类别。人IgG的木瓜蛋白酶Fc片段用异硫氰酸荧光素标记，并与血清一起孵育。通过聚乙二醇沉淀将结合的Fc与游离的Fc分离，并通过沉淀物的荧光进行测量。结果以与正常混合血清结合所得结果的百分比表示。约60%的血清阴性类风湿血清和96%的血清阳性类风湿血清的结果比正常血清平均值高出2个标准差以上。按照相同标准，只有17%的骨关节炎血清给出阳性结果。还推导出一种关系，表明如果在多个Fc浓度下进行测试，结合Fc与游离Fc的双倒数图能够计算出总抗球蛋白以及抗球蛋白与Fc和IgG结合常数的比值。该比值约为1。在标准条件下，结果相当于对存在的总抗球蛋白的约30%进行测量。
