C-Terminal Lysine Processing of Human Immunoglobulin G2 Heavy Chain In Vivo
C-Terminal Lysine Processing of Human Immunoglobulin G2 Heavy Chain In Vivo
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DOI：
10.1002/bit.22933
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发表时间：
2011-02-01
影响因子：
3.8
通讯作者：
Flynn, Gregory C.
中科院分区：
文献类型：
--
作者：
Cai, Bing;Pan, Hai;Flynn, Gregory C.
虽然人IgG重链基因编码c端赖氨酸，但从血清中分离的内源性抗体大多不存在该残基。一些低但可变水平的c端赖氨酸存在于哺乳动物细胞培养系统中表达的治疗性抗体中。在这里，我们监测了重组人IgG2抗体静脉注射到人体内后c端赖氨酸的加工。通过亲和纯化从血清样品中分离的治疗性抗体的肽图谱用于定量体内c端赖氨酸水平随时间的变化。发现c端赖氨酸残基在体内迅速丢失，半衰期约为1小时（62分钟）。体内c端赖氨酸加工可以在体外复制，但在人血清中孵育速度更快。预处理血清在灭活羧基肽酶U的条件下，产生的体外c端赖氨酸加工率与体内更接近。从人血中分离的内源性IgG含有非常低水平的c -末端赖氨酸（约0.02%），与预期抗体循环半衰期和计算的c -末端赖氨酸加工速率一致。因此，低残留IgG2 c端赖氨酸在体内被快速加工，这种加工可能发生在循环中的内源性抗体上。Biotechnol。Bioeng。2011;108: 404 - 412。(C) 2010 Wiley期刊公司
Although human IgG heavy chain genes encode a C-terminal lysine, this residue is mostly absent from the endogenous antibodies isolated from serum. Some low but variable level of C-terminal lysine is present on therapeutic antibodies expressed in mammalian cell culture systems. Here, we monitored the C-terminal lysine processing of a recombinant human IgG2 antibody after intravenous injection into human subjects. Peptide mapping of the therapeutic antibody isolated from serum samples by affinity purification was used to quantify the C-terminal lysine levels over time in vivo. The C-terminal lysine residue was found to be rapidly lost in vivo with a half life of about an hour (62 min). In vivo C-terminal lysine processing could be reproduced in vitro, but at a faster rate, by incubating in human serum. Pretreated serum, under conditions used to inactivate carboxypeptidase U, generated in vitro C-terminal lysine processing rates that more closely matched those in vivo. Endogenous IgG, isolated from human blood, contained very low levels of C-terminal lysine (similar to 0.02%), consistent with the expected circulating half life of antibodies and the calculated C-terminal lysine processing rate. Thus, the low residual IgG2 C-terminal lysine is rapidly processed in vivo and such processing likely occurs on endogenous antibodies in circulation. Biotechnol. Bioeng. 2011;108: 404-412. (C) 2010 Wiley Periodicals, Inc.