Antigen specificity and tumour targeting efficiency of a human carcinoembryonic antigen-specific scFv and affinity-matured derivatives
Antigen specificity and tumour targeting efficiency of a human carcinoembryonic antigen-specific scFv and affinity-matured derivatives
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DOI：
10.1038/bjc.1998.462
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发表时间：
1998-07-01
影响因子：
8.8
通讯作者：
Allen, D
中科院分区：
文献类型：
--
作者：
Jackson, H;Bacon, L;Allen, D
我们已经研究了CEA 6的生物学特性，CEA 6是通过噬菌体展示分离的人癌胚抗原（CEA）特异性单链抗体（scFv），以及通过亲和力成熟获得的5个相关克隆，并选择用于提高解离速率（K-off）。通过免疫细胞化学，所有克隆都与CEA阳性的人类谣言强烈特异性结合，并且与正常结肠显示出可忽略的交叉反应性。对人肝细胞上的单链抗体进行流式细胞术表明，突变导致精细表位特异性发生变化。所有单体scFv都已被放射性碘标记，有效地保留了全部结合活性。单次静脉注射到携带人结肠肿瘤异种移植物的裸鼠中证实了在所有情况下的肿瘤靶向。如在其他研究中所报道的，肾脏是在早期时间点消除scFv的主要途径。亲本抗体CEA 6的肿瘤结合在24小时时始终给出最高的肿瘤-血液比率（平均值16：1），相对于CEA 6具有七倍降低的K-off的克隆T06 D11在24小时时显示肿瘤摄取无差异，但在肿瘤部位持续的时间长于CEA 6。该研究表明，当在该模型中检查时，结合亲和力和肿瘤停留时间之间可能存在相关性。
We have examined the biological properties of CEA6, a human carcinoembryonic antigen (CEA)-specific single-chain Fv (scFv) isolated by phage display, and five related clones derived by affinity maturation and selected for improved off-rate (K-off). All clones bind strongly and specifically to CEA-positive human rumours by immunocytochemistry and show negligible cross-reactivity with normal colon. Flow cytometry of scFv on human liver cells indicates a shift in fine epitope specificity resulting from mutagenesis. All monomeric scFv have been radioiodinated, retaining effectively full binding activity. A single intravenous injection into nude mice bearing human colon tumour xenografts confirms tumour targeting in all cases. As reported in other studies, the kidney is the main route of elimination of scFv at early time points. Tumour binding of the parental antibody CEA6 consistently gives the highest rumour-blood ratios at 24 h (mean 16:1), Clone TO6D11, which has a sevenfold reduced K-off, relative to CEA6, showed no difference in tumour uptake at 24 h but persisted at the tumour site for longer than CEA6, This study demonstrates a possible correlation between binding affinity and tumour residence time when examined in this model.