单克隆抗体 (ｍＡｂ)Ｖ区ｃＤＮＡ序列的克隆是构建单链抗体 (ＳｃＦｖ)的关键一步[1 ] 。通常是在抗体Ｖ区序列两头 5′和 3′端设计带简并碱基的引物 ,用普通ＰＣＲ法进行扩增[2 ] 。该法虽看似简单 ,但局限性很大 ,若遇到同源性差且复杂的序列 ,则难以获得。同时 ,因带有简 Cloning of V region cDNA of monoclonal antibody (mAb) is a key step in the construction of single chain antibody (ScFv) [1]. Primers with degenerate bases are usually designed on both the 5 ’and 3’ ends of the V region sequence of the antibody and amplified by the ordinary PCR method [2]. The law, though seemingly simple, has great limitations and is difficult to obtain if it encounters sequences with poor homology and complexity. At the same time, with Jane