Matsuzaki H, Haruta Y, Fukukawa T, Barcos M P, Seon B K
Cancer Res. 1987 Apr 15;47(8):2160-6.
In the present study we have generated four new monoclonal antibodies (mAbs), termed SN5, SN5a, SN5b, and SN5c, which are directed toward the human common acute lymphoblastic leukemia antigen (CALLA). SN5 and SN5c were generated separately by immunizing two mice with a leukemia antigen preparation isolated from uncultured non-T-/non-B-acute lymphoblastic leukemia cells whereas SN5a and SN5b were generated by immunizing a third mouse with intact KM-3 (a cultured non-T-/non-B-acute lymphoblastic leukemia cell line) cells. It was found that the binding activities of mAbs SN5 and SN5c generated by using an isolated leukemia antigen preparation were approximately twice as large as those of mAbs SN5a and SN5b generated by using intact leukemia cells. All four of the present mAbs induced antigenic modulation of CALLA on the leukemia cells in vitro; subclasses of mAbs appear to be an important factor which influences the kinetics of antigenic modulation. SN5, SN5a, and SN5c immunoprecipitated a distinct Mr 100,000 component from detergent-solubilized cell membrane antigens but SN5b failed to do so. These four mAbs together with J5, another anti-CALLA mAb, were individually tested in a solid phase radioimmunoassay for reactivity with the detergent extracts of various human tissues, i.e., kidney, lymph node, spleen, brain, liver, pancreas, lung, and heart. SN5, SN5a, SN5c, and J5 showed reaction only with kidney whereas SN5b did not show significant reaction with any tissues including kidney. However, SN5b as well as SN5 showed a significant reaction with kidney in an immunoperoxidase-staining test. These results indicate that the interaction of SN5b with a unique epitope on the CALLA moleucle is strongly disturbed by relatively mild detergents (deoxycholate, taurocholate, and Nonidet P-450). These detergents did not significantly disturb the reaction between other mAbs (SN5, SN5a, and SN5c) and the corresponding epitopes on the CALLA molecule. Competitive binding experiments show that the three epitopes recognized by SN5, SN5b, and SN5c are sufficiently close to each other to allow complete or nearly complete reciprocal inhibition of binding to CALLA present on leukemia cells. Peculiar inhibition patterns, however, were observed between SN5a and the other three mAbs. SN5, SN5b, and SN5c inhibited only partially the subsequent binding of SN5a to the leukemia cells. Conversely, SN5a inhibited nearly fully the subsequent bindings of SN5, SN5b, and SN5c. These results suggest another unique epitope defined by SN5a.(ABSTRACT TRUNCATED AT 400 WORDS)
在本研究中，我们制备了四种新的单克隆抗体（mAb），分别命名为SN5、SN5a、SN5b和SN5c，它们针对人类普通急性淋巴细胞白血病抗原（CALLA）。SN5和SN5c是通过用从未培养的非T/非B急性淋巴细胞白血病细胞中分离的白血病抗原制剂免疫两只小鼠分别制备的，而SN5a和SN5b是通过用完整的KM-3（一种培养的非T/非B急性淋巴细胞白血病细胞系）细胞免疫第三只小鼠制备的。结果发现，使用分离的白血病抗原制剂制备的mAb SN5和SN5c的结合活性大约是使用完整白血病细胞制备的mAb SN5a和SN5b的两倍。本研究中的所有四种mAb在体外均能诱导白血病细胞上CALLA的抗原调变；mAb的亚类似乎是影响抗原调变动力学的一个重要因素。SN5、SN5a和SN5c从去污剂溶解的细胞膜抗原中免疫沉淀出一条明显的分子量为100,000的条带，但SN5b未能做到。这四种mAb与另一种抗CALLA mAb J5一起，分别在固相放射免疫测定中检测与各种人体组织（即肾脏、淋巴结、脾脏、大脑、肝脏、胰腺、肺和心脏）去污剂提取物的反应性。SN5、SN5a、SN5c和J5仅与肾脏有反应，而SN5b与包括肾脏在内的任何组织均无明显反应。然而，在免疫过氧化物酶染色试验中，SN5b以及SN5与肾脏有明显反应。这些结果表明，相对温和的去污剂（脱氧胆酸盐、牛磺胆酸盐和Nonidet P-450）会强烈干扰SN5b与CALLA分子上独特表位的相互作用。这些去污剂并未显著干扰其他mAb（SN5、SN5a和SN5c）与CALLA分子上相应表位的反应。竞争性结合实验表明，SN5、SN5b和SN5c识别的三个表位彼此足够接近，以至于能完全或几乎完全相互抑制与白血病细胞上CALLA的结合。然而，在SN5a与其他三种mAb之间观察到了特殊的抑制模式。SN5、SN5b和SN5c仅部分抑制随后SN5a与白血病细胞的结合。相反，SN5a几乎完全抑制随后SN5、SN5b和SN5c与白血病细胞的结合。这些结果提示由SN5a定义的另一个独特表位。（摘要截断于400字）
