【摘要】 目的　鉴定能被BAC5单抗识别的定位于鼻咽癌细胞表面的抗原表位。方法　应用BAC5单抗作为靶抗体对噬菌体展示的随机 12肽文库进行 3轮生物淘洗 ,用抗体捕获和竞争试验的夹心ELISA方法选择和鉴定阳性噬菌体克隆 ,对阳性和阴性噬菌体的外源性DNA片段进行序列分析 ,推导和比较由这些噬菌体所展示的多肽的氨基酸序列。结果　通过 3轮生物淘洗能被抗体捕获的噬菌体克隆为 77% (35 / 45 )。用竞争试验从所捕获的克隆中测得 8个阳性克隆。来自这 8个克隆的噬菌体展示 3种外源多肽 ,即 H Q S H Y P Y P V V S L (4 / 8) , Q N Q A W F S Q P P V R M (3/ 8)和 T Q A Y K G F P V L P S (1/ 8) ,与来自阴性克隆的多肽序列 N H Q S T F W Q K W T A (6 / 6 )比较 ,前 3个序列在靠近肽的N端都具有相同的脯氨酸 (P)和缬氨酸 (V)结构 ( P V )。结论　BAC5单抗能识别近N端含有脯氨酸和缬氨酸结构的多肽。这些多肽可能模拟存在于鼻咽癌细胞表面 ,与BAC5单抗相关的抗原表位的构象更多还原

【Abstract】 Objective To determine the epitope relating to BAC5 McAb, a kind of monoclonal antibody located on the surface of nasopharyngeal carcinoma (NPC) cells. Methods Using BAC5 McAb as selected target 3 rounds of biopanning to a 12 mer random peptide library (RPL) displayed by M13 phages were carried out. The positive M13 phage clones were selected and identified by a sandwich ELISA. The exogenous DNA fragments in the positive/negative M13 phages were sequenced to deduce and compare the sequence of the amino acids of exogenous peptides during the phage clones. Results 77% (35/45) of the phages eluted from the 3rd round of biopanning was captured by BAC5 McAb. Three peptides were displayed by M13 phages from the 8 positive clones identified with competitive assay. The same character of “ P V ” structure existed near N terminus of the 3 different peptides, i.e. H Q S H Y P Y P V V S L (4/8), Q N Q A W F S Q P V R M (3/8) and T Q A Y K G F P V L P S (1/8) in comparison with the peptide“ N H Q S T F W Q K W T A ” displayed by M13 phages from the random selective negative clones (6/6). Conclusion BAC5 McAb recognized the three kinds of peptides with P V structure near N terminus. These peptides shared the structure with the epitope on the surface of NPC cells.更多还原