Studies of antibody therapy for treatment of adult T-cell leukemia targeting surface carbohydrate molecules

利用DNA芯片技术综合分析人T细胞白血病病毒1型（HTLV-1）感染和未感染T细胞株的基因表达，发现CD70是一个在成人T细胞白血病（ATL）细胞表面高特异性表达的分子。通过实时荧光定量PCR对糖基转移酶基因表达的进一步分析和质谱对细胞表面糖链的高通量分析证实了ATL细胞特异性糖链的存在。此外，利用新开发的荧光连接化合物，成功地将ATL细胞表面糖链固定在芯片上。利用人单链病毒（scFv）噬菌体文库，成功分离出ATL细胞系特异性的单链病毒。scFv识别的抗原是HLA-DR1β，该抗原在ATL细胞表面也高表达。scFv以低浓度二聚体形式诱导ATL细胞株凋亡。为了获得与ATL细胞特异性表面糖抗原结合的scFv，通过在单框架抗体的互补决定区（CDR）上引入随机突变，构建了一个新的合成scFv文库。

Comprehensive analysis for the gene expression of human T-cell leukemia virus type 1 (HTLV-1)-infected and uninfected T cell lines by DNA microarray revealed that CD70 was a molecule highly and specifically expressed on the surface of adult T-cell leukemia (ATL) cells. Further analysis for the gene expression of glycosyltransferases by real-time PCR and high-throughput analysis of cell surface sugar chains by mass spectrometry demonstrated the existence of several ATL cell-specific sugar chains. In addition, with a newly developed fluorescent linker compound, the surface sugar chains of ATL cells were successfully immobilized on a chip. Using a human single chain Fv (scFv) phage library, a scFv specific to an ATL cell line was successfully isolated. The antigen recognized by the scFv was HLA-DR1β, which was also highly expressed on the surface of ATL cells. The scFv could induce the apoptosis of the ATL cell line at low concentrations in its dimer form. To obtain the scFv that binds to ATL cell-specific surface sugar antigens, a novel synthetic scFv library was constructed by introducing random mutations on the complementary determining regions (CDR) of a single frame antibody.