Molecular evidence that SJL reticulum cell sarcomas are derived from pre-B cell. Clonal rearrangement of heavy chain but not of light chain immunoglobulin genes.
Molecular evidence that SJL reticulum cell sarcomas are derived from pre-B cell. Clonal rearrangement of heavy chain but not of light chain immunoglobulin genes.
复制标题
分子证据表明 SJL 网状细胞肉瘤源自前 B 细胞。
作者：
H. Nakauchi;H. Osada;H. Yagita;K. Okumura
为探讨SJL网状细胞肉瘤(RCS)的克隆起源，对其进行了双色细胞膜染色和分子生物学分析。流式细胞仪分析表明，SJL RCS中约有50%~60%的Thy-1阳性细胞和20%~30%的B220阳性细胞，其中大部分Thy-1阳性细胞为L3T4阳性，少数Lyt-2阳性。尽管细胞膜分析显示SJL RCS具有多形性，但当用免疫球蛋白重链J片段(JH)探测从肿瘤获得的DNA时，我们观察到该基因的克隆性重排。细胞分选实验结合使用JH基因探针的Southern杂交结果证实，这些克隆扩增的细胞是Ia和B220抗原阳性的。此外，所有来自给定小鼠的肿瘤都显示出相同的重排模式。然而，当用T细胞受体β链基因或免疫球蛋白kappa或lambda轻链基因探测DNA时，没有观察到克隆重排。根据这些数据，我们得出结论，SJL RCS是一种B细胞肿瘤，肿瘤发生在未成熟的B细胞阶段。
In order to investigate the clonal origin of SJL reticulum cell sarcoma (RCS), two-color cell membrane-staining and molecular biologic analyses were performed. Flow cytometric analysis revealed that the SJL RCS consists of about 50 to 60% Thy-1-positive and 20 to 30% B220-positive cells and that the majority of the Thy-1-positive cells are L3T4-positive, whereas a few are Lyt-2-positive. In spite of this pleomorphic nature of SJL RCS shown by cell membrane analysis, when the immunoglobulin heavy chain J segment (JH) was used to probe the DNA obtained from the tumor, we observed clonal rearrangements of the gene. Results of the cell-sorting experiment combined with Southern hybridization using the JH gene probe confirmed that those clonally expanding cells are Ia and B220 antigen-positive. Furthermore, all tumors derived from a given mouse showed the same rearrangement pattern. However, no clonal rearrangement was observed when the DNA was probed with the T cell receptor beta-chain gene or with immunoglobulin kappa- or lambda-light chain genes. From these data, we conclude that SJL RCS is a tumor of B cells and that the neoplastic event takes place at an immature B cell stage.