Department of Applied Biochemistry, Tokai University, Kanagawa, Japan.
Biosci Trends. 2010 Dec;4(6):308-11.
Oncogenic antigens such as Tn-antigen (GalNAcα-Ser/Thr) are involved in metastatic processes and are associated with a poor prognosis, thus representing excellent targets for cancer intervention. Available anti-Tn antibodies which can be applied for therapeutics or diagnostics are severely limited mostly because the Tn-antigen epitope by itself is too small to be antigenic in addition to the fact that many carbohydrates are self-antigens. To characterize anti-Tn monoclonal antibodies as well as to perform panning and screening for isolation of anti-Tn single chain variable fragments from phage-display libraries, a large quantity of inexpensive Tn-antigens are needed. In this study, thus, glycophorin A which is a highly glycosylated sialoglycoprotein with approximately 12 O-glycans was sequentially treated with sialidase and β-galactosidase to remove sialic acid and galactose residues. The resulted product was shown to be an asialo-agalacto-glycophorin A which is reactive to an anti-Tn-antigen antibody. The simple preparation procedures described here would greatly help production and characterization of potentially valuable anti-Tn-antigen antibodies, which can be readily developed for cancer therapeutics and diagnostics.
癌基因抗原，如 Tn 抗原（GalNAcα-Ser/Thr），参与转移过程，并与预后不良相关，因此是癌症干预的极佳靶点。可用于治疗或诊断的现有抗 Tn 抗体受到严重限制，主要是因为 Tn 抗原表位本身太小，无法作为抗原，此外许多碳水化合物是自身抗原。为了鉴定抗 Tn 单克隆抗体，并从噬菌体展示文库中进行淘选和筛选分离抗 Tn 单链可变片段，需要大量廉价的 Tn 抗原。因此，在这项研究中，高度糖基化的唾液糖蛋白糖蛋白 A 首先用唾液酸酶和β-半乳糖苷酶处理，以去除唾液酸和半乳糖残基。所得产物为与抗 Tn 抗原抗体反应的无唾液酸、无半乳糖糖蛋白 A。此处描述的简单制备程序将极大地有助于潜在有价值的抗 Tn 抗原抗体的生产和鉴定，这些抗体可用于癌症治疗和诊断。
