Eisenberg R A, Craven S Y, Cohen P L
J Immunol. 1987 Aug 1;139(3):728-33.
Antibodies to the nuclear ribonucleoprotein Sm are found in 25% of MRL/Mp-lpr/lpr mice, which develop a syndrome similar to human systemic lupus erythematosus. We have previously described that these autoantibodies are relatively restricted to the IgG2a isotype. In the current study, we analyze the isotype distribution of anti-Sm antibodies in these mice over time. The most common pattern observed was an initial response of the IgG2a isotype, which progressed such that this isotype was the major one at the time of peak response. No IgM to IgG class switch was observed. Additional studies directed at the clonality of the anti-Sm response indicated that both kappa- and lambda-light chains could be involved, and that the isoelectric focusing pattern of the anti-Sm antibodies was in general characteristic of multiple spectrotypes. These results also support a special role for the IgG2a isotype in the anti-Sm response in MRL/Mp-lpr/lpr mice. Despite this heavy chain isotype restriction, the response usually evidences substantial diversity, which suggests either multiple B cell clones or somatic mutation of antibody variable region genes.
在25%的MRL/Mp-lpr/lpr小鼠中发现了针对核糖核蛋白Sm的抗体，这些小鼠会发展出一种类似于人类系统性红斑狼疮的综合征。我们之前曾描述过，这些自身抗体相对局限于IgG2a同种型。在当前研究中，我们分析了这些小鼠体内抗Sm抗体的同种型分布随时间的变化情况。观察到的最常见模式是IgG2a同种型的初始反应，这种反应会持续发展，以至于在反应高峰期该同种型成为主要的同种型。未观察到从IgM到IgG的类别转换。针对抗Sm反应的克隆性进行的进一步研究表明，κ链和λ链都可能参与其中，并且抗Sm抗体的等电聚焦模式总体上具有多种光谱型的特征。这些结果也支持了IgG2a同种型在MRL/Mp-lpr/lpr小鼠抗Sm反应中的特殊作用。尽管存在这种重链同种型限制，但该反应通常表现出显著的多样性，这表明可能存在多个B细胞克隆或抗体可变区基因的体细胞突变。
