Lindmo T, Boven E, Mitchell J B, Morstyn G, Bunn P A
Cancer Res. 1985 Oct;45(10):5080-7.
The anti-melanoma antibody 9.2.27 localizes to melanoma cells when administered i.v. to melanoma patients, but high doses of this antibody alone have no specific cytotoxic effect in vivo. To determine whether radiolabeled antibodies would exhibit specific antimelanoma cytotoxicity in vitro, cell survival curves were established for NCl-N892 human melanoma cells treated with 125I-labeled 9.2.27 monoclonal antibody. The binding capacity per cell was 5 X 10(5) molecules of 9.2.27 immunoglobulin G, and the association constant of binding was 10(10) M-1. Antibody preparations with specific radioactivities of 9-80 microCi/micrograms were used. Colony-forming ability after in vitro exposure to 125I-9.2.27 was determined by a 1-h antibody incubation at saturating concentrations, washing, and cell freezing for various exposure durations. Colony survival was dose dependent, varying with the radioactivity per cell and the exposure time. The survival curves demonstrated no shoulder effect and had a 37% incremental survival dose of 0.5-0.9 X 10(5) decays/cell. Selective killing of melanoma cells was demonstrated in experiments where NCl-N417 lung cancer cells were mixed with the melanoma cells prior to antibody treatment. The NCl-N417 cells did not express the melanoma-associated antigen, were more sensitive to conventional external irradiation than were the melanoma cells, and could easily be distinguished from them by different growth morphology. In spite of a growth advantage for the melanoma cells in the clonogenic assay, the antigen-negative lung cancer cells selectively survived the treatment and were the only surviving cells after 15 days of exposure.
抗黑色素瘤抗体9.2.27经静脉注射给予黑色素瘤患者时会定位于黑色素瘤细胞，但单独使用高剂量的该抗体在体内没有特异性细胞毒性作用。为了确定放射性标记抗体在体外是否会表现出特异性抗黑色素瘤细胞毒性，建立了用125I标记的9.2.27单克隆抗体处理的NCl-N892人黑色素瘤细胞的细胞存活曲线。每个细胞的结合能力为5×10(5)个9.2.27免疫球蛋白G分子，结合的缔合常数为10(10) M-1。使用比放射性为9-80微居里/微克的抗体制剂。通过在饱和浓度下孵育抗体1小时、洗涤并将细胞冷冻不同暴露时间来确定体外暴露于125I-9.2.27后的集落形成能力。集落存活呈剂量依赖性，随每个细胞的放射性和暴露时间而变化。存活曲线未显示出肩效应，37%的增加存活剂量为0.5-0.9×10(5)次衰变/细胞。在抗体处理前将NCl-N417肺癌细胞与黑色素瘤细胞混合的实验中证明了对黑色素瘤细胞的选择性杀伤。NCl-N417细胞不表达黑色素瘤相关抗原，比黑色素瘤细胞对传统外照射更敏感，并且可以通过不同的生长形态很容易地与它们区分开来。尽管在克隆形成试验中黑色素瘤细胞具有生长优势，但抗原阴性的肺癌细胞在处理后选择性存活，并且是暴露15天后唯一存活的细胞。
