Yamaguchi Y
Dept. of Medical Biology and Parasitology, Jichi Medical School, Tochigi, Japan.
Gan To Kagaku Ryoho. 1994 Jul;21(8):1287-93.
Interleukin-5 (IL-5) is a glycoprotein with molecular weight 40 to 50 kDa that consists of homodimer. The murine cDNA encodes 133 amino acids with a signal sequence of 18 amino acids. The human cD NA codes for a protein with 134 amino acids in which the first 19 are the predicted signal sequence. There is 70% homology at the amino acid level between murine and human IL-5. IL-5 R alpha chain cDNA encodes p 60 that binds IL-5 with low affinity. The beta subunit of IL-5, GM-CSF, and IL-3 receptor complexes is shared and these receptors show some functional cross-reactivity. Both alpha and beta chains of IL-5 R belong to a cytokine receptor superfamily. It is important to note that whilst murine IL-5 causes the activation of B cells and eosinophil differentiation, human IL-5 only causes eosinophil differentiation. IL-5 plays an important role in eosinophilopoiesis in vivo as well as in vitro.
白细胞介素-5（IL-5）是一种分子量为40至50 kDa的糖蛋白，由同型二聚体组成。小鼠cDNA编码133个氨基酸，带有18个氨基酸的信号序列。人cDNA编码一种含134个氨基酸的蛋白质，其中前19个为预测的信号序列。小鼠和人IL-5在氨基酸水平上有70%的同源性。IL-5Rα链cDNA编码与IL-5低亲和力结合的p60。IL-5、粒细胞-巨噬细胞集落刺激因子（GM-CSF）和IL-3受体复合物的β亚基是共用的，这些受体表现出一些功能交叉反应性。IL-5R的α链和β链均属于细胞因子受体超家族。需要注意的是，虽然小鼠IL-5可导致B细胞活化和嗜酸性粒细胞分化，但人IL-5仅导致嗜酸性粒细胞分化。IL-5在体内外的嗜酸性粒细胞生成中均起重要作用。
