Staub M, Spasokukotskaja T, Benczur M, Antoni F
First Institute of Biochemistry, Semmelweis University Medical School, Budapest, Hungary.
Acta Otolaryngol Suppl. 1988;454:118-24. doi: 10.3109/00016488809125014.
High (HD) and low (LD) density cells were separated on 25% BSA gradient from tonsils of 3-6 years old children. Early B lymphocyte markers and sIg-s were found on the surface of 59-82% of the LD cells. This cell population was 5-6 times more active in DNA synthesis (3H-thymidine incorporation, DNA polymerase activity) than the HD cells. The total uptake of 3H-deoxycytidine was about the same as that of 3H-thymidine. As long as practically all thymidine taken up by the cells was immediately incorporated into DNA (90-95%), only 10-15% of deoxycytidine was incorporated into DNA under the same conditions, indicating different pool sizes for the DNA precursors. The majority of deoxycytidine (70%) was converted and incorporated as dTMP. A considerable part of labeled deoxycytidine could be detected in the soluble pool in form of nucleotides (3-8%), and in an unknown form, called substance X (8-14%). Substance X was purified by TL chromatography and identified by HPLC as deoxycytidine containing liponucleotides, probable precursors for plasmamembranes. The preferential utilisation of deoxycytidine for DNA and membrane synthesis in immature B lymphocytes draws the attention to its function in early events of lymphocyte maturation.
从3至6岁儿童的扁桃体中，通过25%牛血清白蛋白梯度分离出高密度（HD）和低密度（LD）细胞。在59%至82%的LD细胞表面发现了早期B淋巴细胞标志物和表面免疫球蛋白（sIg-s）。该细胞群体在DNA合成（3H-胸腺嘧啶核苷掺入、DNA聚合酶活性）方面的活性比HD细胞高5至6倍。3H-脱氧胞苷的总摄取量与3H-胸腺嘧啶核苷的总摄取量大致相同。由于细胞摄取的几乎所有胸腺嘧啶核苷都立即掺入了DNA（90%至95%），在相同条件下，只有10%至15%的脱氧胞苷掺入了DNA，这表明DNA前体的库大小不同。大部分脱氧胞苷（70%）被转化并以脱氧胸苷一磷酸（dTMP）的形式掺入。相当一部分标记的脱氧胞苷可以以核苷酸的形式（3%至8%）在可溶性池中检测到，还有一部分以未知形式，即物质X（8%至14%）存在。物质X通过薄层层析法纯化，并通过高效液相色谱法鉴定为含脱氧胞苷的脂核苷酸，可能是质膜的前体。未成熟B淋巴细胞中脱氧胞苷优先用于DNA和膜合成，这引起了人们对其在淋巴细胞成熟早期事件中功能的关注。
