The switch from IgM to IgG secretion in single mitogen-stimulated B-cell clones.
The switch from IgM to IgG secretion in single mitogen-stimulated B-cell clones.
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DOI：
10.1084/jem.147.6.1744
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发表时间：
1978-06-01
期刊：
影响因子：
--
通讯作者：
Melchers F
中科院分区：
文献类型：
--
作者：
Andersson J;Coutinho A;Melchers F
在培养条件下，通过限制稀释分析，在体外测定了丝裂原反应性B细胞产生Ig斑块形成细胞(PFC)反应的频率。培养条件允许每个生长诱导的B细胞生长和成熟为Ig分泌细胞的克隆。6-8周龄C3H/Tif和C57BL/67小鼠脾中分泌免疫球蛋白的细胞的脂多糖和脂蛋白反应前体的频率在30-40个B细胞中的1/30到1/40之间，因此只有分泌IgM克隆的十分之一。所有的免疫球蛋白分泌细胞都是通过换入以前含有免疫球蛋白M分泌细胞的克隆而发展起来的。这一点在两个实验中得到了证明，在这两个实验中，产生IgM分泌细胞克隆的有丝分裂原反应前体的总数有限，以至于所有响应的培养物中有82%或90%来自一个前体。因此，在第一次和第二次实验中的480种和720种培养中，有86种和98种培养呈阳性，在第5天产生了IgM分泌细胞。当同样的培养在第7天被检测时，有9种和10种培养呈阳性。所有19种含有免疫球蛋白分泌细胞的培养物此前都含有免疫球蛋白M分泌细胞。利用Fisher对独立性的精确检验，可以计算出由独立前体产生的免疫球蛋白分泌细胞和免疫球蛋白M分泌细胞的概率。对于这两个实验，这些概率分别为3.4×10(-7)和4.0×10(-9)。由于我们之前已经证明，在有丝分裂原刺激的、正在生长的B细胞克隆中，每个细胞都会分裂，每个分裂细胞都会分泌Ig，因此我们从这些实验中得出结论，在有丝分裂原刺激的B细胞克隆中，绝大多数--在我们的实验中在单个免疫球蛋白M分泌细胞克隆的生长过程中，免疫球蛋白分泌细胞早期或晚期发育。因此，在有丝分裂刺激后的克隆生长过程中，向免疫球蛋白分泌的转换并不是固定的。
The frequency of mitogen-reactive B cells yielding an IgG plaque- forming cell (PFC) response has been determined in vitro by limiting dilution analysis under culture conditions which allow every growth- induced B cell to grow and mature into a clone of Ig-secreting cells. The frequencies of lipopolysaccharide (LPS)-and lipoprotein-reactive precursors for IgG-secreting cells in the spleen of 6--8 wk old C3H/Tif and of C57BL/67 mice were found to be between 1 in 30 and 1 in 40 B cells and, therefore, only one tenth of the frequencies of mitogen- reactive precursors of clones secreting IgM. All IgG-secreting cells developed by switching in clones which previously contained IgM- secreting cells. This was shown in two experiments where the total number of mitogen-reactive precursor yielding IgM-secreting cell clones was limited such that 82 or 90% of all responding cultures originated from one precursor. Thus, of 480 cultures in the first and 720 cultures in the second experiment, 86 and 98 cultures were found positive, yielding IgM-secreting cells at day 5. When the same cultures were assayed at day 7 for IgG-secreting cells 9 and 10 cultures were found positive. All 19 cultures with IgG-secreting cells previously had contained IgM-secreting cells. The probability that IgG-secreting cells and IgM-secreting cells would have arisen from independent precursors can be calculated using Fisher's exact test of independence. For the two experiments those probabilities are 3.4 X 10(-7) and 4.0 X 10(-9). Since we have previously shown that each cell in a mitogen-stimulated, growing B-cell clone divides, and that each dividing cell secretes Ig, we conclude from these experiments that the large majority--in our experiments all--of the IgG-secreting cells in mitogen-stimulated B- cell clones develop by switch from IgM-secreting cells. IgG-secreting cells develop either early or late during growth of a single IgM- secreting cell clone. The switch to IgG secretion, therefore, is not fixed in the time of clonal growth after mitogenic stimulation.