Departments of Process and Product Development, Thousand Oaks, California 91320.
Therapeutic Discovery, Amgen Inc., Thousand Oaks, California 91320.
J Biol Chem. 2013 Jun 7;288(23):16371-16382. doi: 10.1074/jbc.M113.468397. Epub 2013 Apr 25.
During either production or storage, the LC214-HC220 disulfide in therapeutic antibodies can convert to a thioether bond. Here we report that a thioether forms at the same position on antibodies in vivo. An IgG1κ therapeutic antibody dosed in humans formed a thioether at this position at a rate of about 0.1%/day while circulating in blood. Thioether modifications were also found at this position in endogenous antibodies isolated from healthy human subjects, at levels consistent with this conversion rate. For both endogenous antibodies and recombinant antibodies studied in vivo, thioether conversion rates were faster for IgG1 antibodies containing λ light chains than those containing κ light chains. These light chain reaction rate differences were replicated in vitro. Additional mechanistic studies showed that base-catalyzed thioether formation through the light chain dehydrogenation was more preferred on antibodies with λ light chains, which may help explain the observed reaction rate differences.
在生产或储存过程中，治疗性抗体中的 LC214-HC220 二硫键可能会转化为硫醚键。在这里，我们报告说在体内抗体上相同位置形成了硫醚键。在人体中给药的 IgG1κ 治疗性抗体在循环血液中以约 0.1%/天的速度在此位置形成硫醚键。在从健康人类受试者中分离的内源性抗体中也发现了该位置的硫醚修饰，其水平与该转化率一致。对于体内研究的内源性抗体和重组抗体，含 λ 轻链的 IgG1 抗体的硫醚转化率均高于含 κ 轻链的抗体。体外实验也复制了这些轻链反应速率差异。进一步的机制研究表明，通过轻链脱氢作用的碱基催化硫醚形成更倾向于含 λ 轻链的抗体，这可能有助于解释观察到的反应速率差异。
