Fukukawa T, Matsuzaki H, Haruta Y, Hara H, Seon B K
Exp Hematol. 1986 Oct;14(9):850-5.
We have generated and characterized three new monoclonal antibodies (mAbs), termed SN3, SN3a, and SN3b, which are directed to sialic acid of a glycoprotein(s) on human non-T leukemia cells. These mAbs were generated by immunizing mice with an antigen preparation isolated from cell-membrane glycoconjugates of NALM-1, a pre-B leukemia cell line. The initial characterization of the mAbs consisted of a sensitive cellular radioimmunoassay against various cultured human leukemia-lymphoma (HLL) and nonmalignant cell lines. They strongly reacted with all four (all three in the case of SN3a) non-T/non-B HLL cell lines tested and both pre-B HLL cell lines tested. However, they reacted with only one of three B HLL cell lines tested. In addition, these mAbs did not react with other cell lines, which include T- and myelomonocytic HLL cell lines and nonmalignant B-cell lines. Normal peripheral blood cells were also tested; the mAbs reacted with B cells and granulocytes but not with T cells, monocytes, erythrocytes, or platelets. In a test using SN3 and SN3b with uncultured cell specimens derived from various cancer patients, the mAbs primarily reacted with non-T/non-B and B HLL specimens, as well as with chronic myelocytic leukemia specimens. The biochemical nature of antigenic determinants defined by the three mAbs was studied by treating the non-T leukemia cells with sialidase and proteases. The results show that the antigenic determinants defined by these mAbs all contain a sialic acid residue(s) that is attached to the cells via a protein backbone(s). Competitive binding experiments show that binding of SN3 to the leukemia cells was blocked almost completely by SN3a and SN3b, as well as by BA-1. Both SN3 and SN3a are IgG1 antibodies, whereas SN3b is an IgM antibody; SN3b showed a strong complement-mediated cytotoxic activity against non-T leukemia cells.
我们制备并鉴定了三种新的单克隆抗体（mAb），分别命名为SN3、SN3a和SN3b，它们针对人非T白血病细胞上糖蛋白的唾液酸。这些单克隆抗体是通过用从pre - B白血病细胞系NALM - 1的细胞膜糖缀合物中分离出的抗原制剂免疫小鼠而产生的。单克隆抗体的初步鉴定包括针对各种培养的人白血病 - 淋巴瘤（HLL）和非恶性细胞系的灵敏细胞放射免疫分析。它们与所有四种（SN3a为三种）测试的非T/非B HLL细胞系以及两种测试的pre - B HLL细胞系强烈反应。然而，它们仅与三种测试的B HLL细胞系中的一种反应。此外，这些单克隆抗体不与其他细胞系反应，这些细胞系包括T和髓单核细胞HLL细胞系以及非恶性B细胞系。还测试了正常外周血细胞；单克隆抗体与B细胞和粒细胞反应，但不与T细胞、单核细胞、红细胞或血小板反应。在使用SN3和SN3b对来自各种癌症患者的未培养细胞标本进行的测试中，单克隆抗体主要与非T/非B和B HLL标本以及慢性粒细胞白血病标本反应。通过用唾液酸酶和蛋白酶处理非T白血病细胞，研究了由这三种单克隆抗体定义的抗原决定簇的生化性质。结果表明，这些单克隆抗体定义的抗原决定簇均含有通过蛋白质主链与细胞相连的唾液酸残基。竞争性结合实验表明，SN3a、SN3b以及BA - 1几乎完全阻断了SN3与白血病细胞的结合。SN3和SN3a都是IgG1抗体，而SN3b是IgM抗体；SN3b对非T白血病细胞表现出强烈的补体介导的细胞毒活性。
