Asao H, Takeshita T, Nakamura M, Nagata K, Sugamura K
Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan.
Int Immunol. 1990;2(5):469-72. doi: 10.1093/intimm/2.5.469.
The biosynthesis of human interleukin 2 receptor (IL-2R)p75 was studied with TU27 monoclonal antibody (TU27 mAb) specific for the IL-2Rp75. TU27 mAb specifically immunoprecipitated not only p75 with a mol. wt of 70-82 kd and an isoelectric point (pl) of 4.4-4.7 but also p70 with a mol. wt of 70 kd and a pl of 4.7 from the cell lysate of MT-2, a human T cell line constitutively expressing IL-2R, labeled metabolically with [35S]cysteine. In contrast, only p75 was detected when the lysate of MT-2 cells surface-labeled with Na125I was immunoprecipitated with TU27 mAb. These results suggest that p75 is a mature form of IL-2Rp75 expressed on the cell surface. Pulse-chase experiments demonstrated that p70 could be converted into IL-2Rp75 by post-translational processing. Studies with monensin, endoglycosidase F, and neuraminidase showed that the mature IL-2Rp75 molecule is generated through N-linked glycosylation and sialylation of the p70 precursor.
使用针对人白细胞介素2受体（IL-2R）p75的TU27单克隆抗体（TU27 mAb）研究了人IL-2R p75的生物合成。TU27 mAb不仅能特异性免疫沉淀分子量为70 - 82 kd、等电点（pI）为4.4 - 4.7的p75，还能从用[35S]半胱氨酸进行代谢标记的人T细胞系MT-2（组成性表达IL-2R）的细胞裂解物中免疫沉淀分子量为70 kd、pI为4.7的p70。相比之下，当用Na125I对MT-2细胞进行表面标记后的裂解物用TU27 mAb进行免疫沉淀时，仅检测到p75。这些结果表明p75是在细胞表面表达的IL-2R p75的成熟形式。脉冲追踪实验表明，p70可通过翻译后加工转化为IL-2R p75。用莫能菌素、内切糖苷酶F和神经氨酸酶进行的研究表明，成熟的IL-2R p75分子是通过p70前体的N-连接糖基化和唾液酸化产生的。
