Department of Molecular Cell Biology, Institute of DNA Medicine, Research Center for Medical Sciences, Minato-ku, Tokyo 105-8461, Japan.
IEEE Trans Nanobioscience. 2011 Mar;10(1):30-5. doi: 10.1109/TNB.2011.2125800.
Among the immunoglobulins, IgM class-antibodies are now considered to be potent immunological reagents for anticancer remedies. However, only a few reports are available about the effective labeling of IgM with enzymes, fluorescence, or other bioreactive reagents. Here, we report an effective application of luminescent semiconductive nanoparticles, quantum dots (QDs), as a labeling material of the IgM antibody. The CdSe carboxyl QDs were reacted with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysulfo- succinimide in 2-(morpholino) ethanesulfonic acid. The reacted QDs were then coupled to JT95 IgM antibody, which recognizes thyroid carcinoma associated antigen. The specificity and activity of the conjugates were tested by immunoblot, immunoquantitive assay and immunohistological imaging. The QDs were firmly conjugated with JT95 IgM monoclonal antibody. In immunoblot assay, QD-JT95 conjugates directly detected the target molecules without obstructing the binding site. In immunoquantitive assay, the conjugates could quantify the antigen in the range of 1.56-100 μg/mL. Also, QDs-labeled antibody detected the antigen on plasma membrane. Our results demonstrate that labeling of JT95 and other IgM class antibodies with QDs is feasible. This approach may be an important method for the medical application of IgM in the diagnosis and treatment of cancers.
在免疫球蛋白中，IgM 类抗体现在被认为是癌症治疗的有效免疫试剂。然而，关于用酶、荧光或其他生物活性试剂有效标记 IgM 的报道很少。在这里，我们报告了将发光半导体纳米粒子，即量子点 (QD)，作为 IgM 抗体标记材料的有效应用。CdSe 羧基 QD 与盐酸 1-乙基-3-(3-二甲基氨基丙基)碳二亚胺和 N-羟基磺基琥珀酰亚胺在 2-(吗啉代)乙磺酸中反应。然后将反应的 QD 与 JT95 IgM 抗体偶联，该抗体识别甲状腺癌相关抗原。通过免疫印迹、免疫定量测定和免疫组织化学成像测试了缀合物的特异性和活性。QD 与 JT95 IgM 单克隆抗体牢固偶联。在免疫印迹分析中，QD-JT95 缀合物直接检测靶分子而不阻断结合位点。在免疫定量测定中，缀合物可以在 1.56-100 μg/mL 的范围内定量抗原。此外，QD 标记的抗体检测到质膜上的抗原。我们的结果表明，用 QD 标记 JT95 和其他 IgM 类抗体是可行的。这种方法可能是 IgM 在癌症诊断和治疗中的医学应用的重要方法。
