Identification of a novel bovine serum protein which is involved in human T-cell leukemia virus type I (HTLV-I)-induced syncytium formation

作     者：Okuma, K Nakamura, M Nakano, S Tanaka, Y Niho, Y 

作者机构：Kyushu Univ Fac Med Dept Internal Med 1 Fukuoka 8128582 Japan Kitasato Univ Sch Sci Dept Biosci Sagamihara Kanagawa Japan 

出 版 物：《ARCHIVES OF VIROLOGY》 (病毒学文献)

年 卷 期：1999年第144卷第1期

页      面：1-18页

核心收录：

学科分类：0710[理学-生物学] 1007[医学-药学(可授医学、理学学位)] 100705[医学-微生物与生化药学] 07[理学] 071005[理学-微生物学] 10[医学] 

主　　题：氨基酸序列 抗体 单克隆 血蛋白质类/生理学 人类嗜T淋巴细胞病毒1型/生理学 白血病 T细胞/代谢 白血病 T细胞/病理学 白血病 T细胞/病毒学 分子序列数据 血小板因子4/遗传学 序列比对 序列同源性 氨基酸 肿瘤细胞 培养的 病毒复制 动物 牛 人类 大鼠 

摘      要：By immunizing rats with cocultured HTLV-I-positive ILT8M2 and HTLV-I-negative MOLT-4 cells, we isolated a monoclonal antibody (mAb), designated as mAb R21, which enhances the syncytium formation induced by coculturing ILT8M2 cells with MOLT-4 cells. The antigen recognized by mAb R21 was found on the surface of all T-cell, fibroblastoid, and epithelial cell lines, and a part of B-cell and myelomonocytoid cell lines. MAb R21 reacted with an approximately 17-kDa protein from ILT8M2 and MOLT-4 cell lysates in both nonreducing and reducing conditions by immunoblotting. Immunoprecipitation experiments using surface-labeled cells revealed that a 17-kDa protein is present on the surface of both ILT8M2 and MOLT-4 cells. Since the enhancing activity by mAb R21 of syncytium formation was observed only in the presence of a factor contained in fetal calf serum (FCS) which seems to bind to mAb R21, we purified this serum factor from FCS using a mAb R21- coupled Sepharose 4B column. The purified protein, designated as R21 protein, was revealed to be O-glycosylated but not N-glycosylated protein of approximately 17 kDa. The partial amino acid sequence of this protein indicates that R21 protein is a novel bovine serum protein which has approximately 90% amino acid homology with bovine platelet factor 4, a member of CXC chemokine family. These results indicate that the R21 protein on the surface of cells and/or in FCS may play an important role in the process of HTLV-I-induced syncytium formation by as yet unknown mechanism.