Mariette X, Brouet J C, Danon F, Tsapis A, Lassoued K
Laboratory of Immunopathology, Hôpital Saint-Louis, Paris, France.
Arthritis Rheum. 1993 Sep;36(9):1315-24. doi: 10.1002/art.1780360916.
To gain insight into the genetic origin of human antilamin autoantibodies, we determined the nucleotide sequence of the light and heavy chain variable region (VL and VH) domains of 5 IgM antibodies directed to lamin B. These antibodies represent a distinct subset of antinuclear antibodies, and their presence is associated with a particular lupus-like syndrome.
We derived and cloned lymphoblastoid cell lines from peripheral blood B cells of 3 patients, selected anti-lamin B-producing subclones, and sequenced the messenger RNA coding for Ig heavy and light chains.
We isolated 2 subclones (1 IgM kappa, 1 IgM lambda) from one patient (FUR) and 2 subclones (both IgM lambda) from another (HER). In contrast, all 8 lines derived from B cells isolated from the third patient (BEN) synthesized identical anti-lamin B IgM kappa antibodies: All VL and VH domains from these 5 IgM were encoded by different VL or VH genes. DH regions were all different, and there was no restriction in the use of JL or JH segments. Analysis of the nucleotide sequence of the VL domains allowed the identification of the putative germinal gene in 3 instances (V kappa IV, Humkv325, and V lambda III.1); the overall ratios of replacement:silent mutations (R:S) were 6.5 and 1.2 in the complementarity-determining regions (CDRs) and framework regions (FRs), respectively. The 2 other lambda sequences belonged to the V lambda III family. With regard to VH domains, 3 of 5 derived from previously identified germline genes (VHIV 4.19, VHIV 4.22, and VHIII 9.1); the overall R:S ratio for these genes was 8 and 1.5 in CDRs and FRs, respectively.
Taken together, these data provide evidence that the repertoire of human antilamin autoantibodies is not restricted and that the antigen (or another kind of selective pressure) plays a role in the generation of autoantibodies to lamin B. This hypothesis is in accordance with the reactivity of these antibodies to discrete epitopes of lamin B.
为深入了解人类抗板层素自身抗体的遗传起源，我们测定了5种针对板层素B的IgM抗体轻链和重链可变区（VL和VH）结构域的核苷酸序列。这些抗体代表了抗核抗体的一个独特亚群，它们的存在与一种特定的狼疮样综合征相关。
我们从3名患者的外周血B细胞中获得并克隆了淋巴母细胞系，筛选出产生抗板层素B的亚克隆，并对编码Ig重链和轻链的信使RNA进行测序。
我们从一名患者（FUR）中分离出2个亚克隆（1个IgM κ，1个IgM λ），从另一名患者（HER）中分离出2个亚克隆（均为IgM λ）。相比之下，从第三名患者（BEN）分离的B细胞衍生的所有8个细胞系均合成相同的抗板层素B IgM κ抗体：这5种IgM的所有VL和VH结构域均由不同的VL或VH基因编码。DH区域各不相同，在使用JL或JH片段方面没有限制。对VL结构域核苷酸序列的分析使得在3个实例中鉴定出推定的胚系基因（VκIV、Humkv325和VλIII.1）；互补决定区（CDR）和框架区（FR）中置换：沉默突变（R:S）的总体比率分别为6.5和1.2。另外2个λ序列属于VλIII家族。关于VH结构域，5个中有3个源自先前鉴定的种系基因（VHIV 4.19、VHIV 4.22和VHIII 9.1）；这些基因在CDR和FR中的总体R:S比率分别为8和1.5。
综上所述，这些数据提供了证据，表明人类抗板层素自身抗体的库不受限制，并且抗原（或另一种选择性压力）在抗板层素B自身抗体的产生中起作用。这一假设与这些抗体对板层素B离散表位的反应性一致。
