Mozo L, Rivas D, Zamorano J, Gutierrez C
Department of Immunology, Hospital Central de Asturias, Centro Universitario, Oviedo, Spain.
J Immunol. 1993 May 15;150(10):4261-9.
IL-4R have been described in unstimulated human T and B lymphocytes. However, a precise comparative study on the expression and regulation of IL-4R in isolated human T and B cell populations has not yet been fully assessed. We examined the mRNA levels and the cell membrane expression of IL-4R in freshly isolated T and B lymphocytes as well as in in vivo- and in vitro-stimulated cells. IL-4R protein expression and transcript levels were higher in tonsillar unstimulated B cells than in T cells. Splenic and peripheral blood B lymphocytes also expressed higher surface IL-4R in their membranes than T cells did. Large B lymphocytes from tonsils (in vivo-activated cells) obtained by Percoll gradient centrifugation displayed higher IL-4R levels than resting cells. On activation in vitro of T lymphocytes with IL-2 or PHA, slight increments on the IL-4R mRNA and protein levels were achieved. However, maximal levels of IL-4R expression were obtained on T cell incubation with IL-4 at a concentration of 100 U/ml. Similarly, the same concentration of this lymphokine up-regulated the surface IL-4R molecules and the IL-4R mRNA levels in purified B lymphocytes. Cross-linkage of surface Ig by insolubilized anti-IgM potentiated the effect of IL-4 in up-regulating IL-4R expression in B cells, probably by inducing outgrowth of IL-4R positive subpopulations. The B cell mitogen, Staphylococcus Aureus Cowan I, although inducing cell proliferation, was ineffective in promoting new receptor synthesis. Cell proliferation was not required for IL-4-dependent IL-4R up-regulation on both T and B lymphocytes.
白细胞介素-4受体（IL-4R）已在未受刺激的人T淋巴细胞和B淋巴细胞中被描述。然而，关于分离的人T细胞和B细胞群体中IL-4R表达和调控的精确比较研究尚未得到充分评估。我们检测了新鲜分离的T淋巴细胞和B淋巴细胞以及体内和体外刺激细胞中IL-4R的mRNA水平和细胞膜表达。扁桃体未受刺激的B细胞中IL-4R蛋白表达和转录水平高于T细胞。脾脏和外周血B淋巴细胞细胞膜上表面IL-4R的表达也高于T细胞。通过Percoll梯度离心获得的扁桃体大B淋巴细胞（体内活化细胞）显示出比静息细胞更高的IL-4R水平。用白细胞介素-2（IL-2）或植物血凝素（PHA）体外激活T淋巴细胞时，IL-4R的mRNA和蛋白水平略有增加。然而，当T细胞与浓度为100 U/ml的IL-4孵育时，可获得IL-4R表达的最高水平。同样，相同浓度的这种淋巴因子上调了纯化B淋巴细胞表面的IL-4R分子和IL-4R mRNA水平。不溶性抗IgM对表面免疫球蛋白（Ig）的交联增强了IL-4上调B细胞中IL-4R表达的作用，可能是通过诱导IL-4R阳性亚群的生长。B细胞促有丝分裂原金黄色葡萄球菌考恩I型（Staphylococcus Aureus Cowan I）虽然能诱导细胞增殖，但在促进新受体合成方面无效。T淋巴细胞和B淋巴细胞上IL-4依赖的IL-4R上调不需要细胞增殖。
