Chu J L, Gharavi A E, Elkon K B
Clin Exp Immunol. 1986 Mar;63(3):601-7.
The spectrotypes of IgA and IgM rheumatoid factors (RF) were analysed in whole serum as well as immunoglobulin fractions and purified RF from patients with one of three autoimmune disorders. As predicted from the pI ranges of normal human serum IgM and IgA in agarose, IgM RF had near neutral pIs, whereas IgA RF showed more acidic (lower) pI values. Serum IgA and IgM RF from patients with rheumatoid arthritis or the sicca syndrome showed considerable charge heterogeneity whereas IgM RF from mixed cryoglobulinaemia or rheumatoid vasculitis patients showed monoclonal and oligoclonal banding patterns respectively. Clonotypic analysis was best achieved with isolated light and heavy chains from highly purified RF. The IgA RF spectrotypes from unmodified paired serum and saliva IgA were clearly different whereas after desialation, similar pI values and, in one case, similar spectrotypes were observed. These observations are compatible with the hypothesis that serum and saliva IgA RF are derived from similar clonal precursors. The methods used in these studies may also be of use in the analysis of IgA and IgM antibody diversity in a number of other situations.
对三种自身免疫性疾病之一的患者的全血清、免疫球蛋白组分以及纯化的类风湿因子（RF）中的IgA和IgM类风湿因子的光谱类型进行了分析。正如从琼脂糖中正常人血清IgM和IgA的pI范围所预测的那样，IgM RF的pI接近中性，而IgA RF显示出更酸性（更低）的pI值。类风湿关节炎或干燥综合征患者的血清IgA和IgM RF表现出相当大的电荷异质性，而混合性冷球蛋白血症或类风湿性血管炎患者的IgM RF分别表现出单克隆和寡克隆条带模式。从高度纯化的RF中分离出的轻链和重链进行克隆型分析效果最佳。未修饰的配对血清和唾液IgA的IgA RF光谱类型明显不同，而去唾液酸化后，观察到相似的pI值，并且在一个病例中观察到相似的光谱类型。这些观察结果与血清和唾液IgA RF源自相似克隆前体的假设一致。这些研究中使用的方法也可能用于分析许多其他情况下的IgA和IgM抗体多样性。
