Nepom J T, Hellström I, Hellström K E
Proc Natl Acad Sci U S A. 1977 Oct;74(10):4605-9. doi: 10.1073/pnas.74.10.4605.
Serum from mice with growing tumors can prevent ("block") the destruction of tumor cells by immune lymphocytes, as measured in a microcytotoxicity assay. Factors responsible for this blocking activity were purified by binding to immune adsorbents that had been prepared from antibodies obtained by immunizing BALB/c mice to the homologous tumors. Two transplantable BALB/c sarcoma lines with individually different tumor-specific transplantation antigens were studied in parallel. The original tumor-specific blocking activity was recovered by elution of the immune adsorbents; that is, (i) eluates blocked the reduction of surviving tumor cell targets by immune lymphocytes only if the tumor specificity, and (ii) immune adsorbent columns prepared from tumor-immune sera recognized the purified blocking fractions in a tumor-specific fashion, indicating that a portion of the humoral response in the immune mice was directed against a factor that was individually distinct for each tumor. Absorption of eluates with the homologous tumor cells removed their blocking activity, indicating that the blocking factors have antigen-binding properties. Blocking activity in the purified fractions resided in molecules presumptively identified as glycoproteins by affinity chromatography on concanavalin A-Sepharose.
在微量细胞毒性试验中检测发现，患有正在生长肿瘤的小鼠血清可阻止（“阻断”）免疫淋巴细胞对肿瘤细胞的破坏。通过与免疫吸附剂结合来纯化负责这种阻断活性的因子，该免疫吸附剂由用同源肿瘤免疫BALB/c小鼠获得的抗体制备而成。同时研究了两种具有各自不同肿瘤特异性移植抗原的可移植BALB/c肉瘤细胞系。通过洗脱免疫吸附剂可恢复原始的肿瘤特异性阻断活性；也就是说，（i）只有当肿瘤具有特异性时，洗脱液才会阻断免疫淋巴细胞对存活肿瘤细胞靶标的杀伤作用，并且（ii）由肿瘤免疫血清制备的免疫吸附柱以肿瘤特异性方式识别纯化的阻断组分，这表明免疫小鼠中的一部分体液反应针对的是每个肿瘤各自不同的一种因子。用同源肿瘤细胞吸收洗脱液可去除其阻断活性，这表明阻断因子具有抗原结合特性。纯化组分中的阻断活性存在于通过伴刀豆球蛋白A-琼脂糖亲和层析推测鉴定为糖蛋白的分子中。
