Zuber C E, Galizzi J P, Vallé A, Harada N, Howard M, Banchereau J
UNICET, Laboratory for Immunological Research, Dardilly, France.
Eur J Immunol. 1990 Mar;20(3):551-5. doi: 10.1002/eji.1830200314.
Human interleukin 4 (IL 4) up-regulates the expression of CD23 on both resting and "in vivo" activated B cells but induces proliferation and/or differentiation only on "in vitro" activated B lymphocytes. Resting B cells express 360 high-affinity IL 4 receptors (R) per cell (Kd = 25-75 pM). Activation of resting B cells with anti-IgM antibody or Staphylococcus aureus Cowan I (SAC) results in a two-to-threefold increase of IL 4R number without alteration of IL 4R affinity for IL 4. Flow cytometric analysis of biotinylated IL 4 binding shows that IL 4R expression is up-regulated on virtually all anti-IgM-stimulated B cells, but only on a subpopulation of larger cells among SAC-activated B lymphocytes. Culturing cells for 40 h with optimal concentrations of IL 4 does not significantly affect IL 4R levels on resting and anti-IgM-preactivated B lymphocytes but triples IL 4R levels on SAC-preactivated B cells. Removal of IL 4 from cell cultures results in a two-to-fourfold increase of IL 4R levels 2 h later, suggesting an increase in IL 4R turnover. Resting and activated B cells degrade 125I-labeled IL 4 at 37 degrees C. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of IL 4 binding molecules on resting, "in vivo" activated and anti-IgM-activated B cells reveals the same three species of 130, 80-75, 70-65 kDa. Thus, IL 4 displays its different biological activities on resting and activated B cells through IL 4R of the same affinity, gross biochemical structure and ability to mediate IL 4 degradation.
人白细胞介素4（IL-4）可上调静止和“体内”活化B细胞上CD23的表达，但仅对“体外”活化的B淋巴细胞诱导增殖和/或分化。静止B细胞每个细胞表达360个高亲和力IL-4受体（R）（解离常数Kd = 25 - 75 pM）。用抗IgM抗体或金黄色葡萄球菌Cowan I（SAC）激活静止B细胞会导致IL-4R数量增加两到三倍，而IL-4R对IL-4的亲和力不变。对生物素化IL-4结合进行流式细胞术分析表明，IL-4R表达在几乎所有抗IgM刺激的B细胞上均上调，但仅在SAC活化的B淋巴细胞中较大细胞的亚群上上调。用最佳浓度的IL-4培养细胞40小时对静止和抗IgM预活化的B淋巴细胞上的IL-4R水平没有显著影响，但使SAC预活化的B细胞上的IL-4R水平增加两倍。从细胞培养物中去除IL-4会导致2小时后IL-4R水平增加两到四倍，表明IL-4R周转率增加。静止和活化的B细胞在37℃下降解125I标记的IL-4。对静止、“体内”活化和抗IgM活化的B细胞上IL-4结合分子进行十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳分析，发现有相同的三种分子量分别为130、80 - 75、70 - 65 kDa的分子。因此，IL-4通过具有相同亲和力、总体生化结构和介导IL-4降解能力的IL-4R在静止和活化的B细胞上表现出不同的生物学活性。
