抗肿瘤单抗3H11对应抗原cDNA片段的克隆

单克隆抗体３Ｈ１１能与多种肿瘤细胞特异结合，克隆其对应抗原无疑具重要意义．用胃癌细胞ＭＧＣ８０３构建ｃＤＮＡ表达文库，通过抗体３Ｈ１１对其进行原核表达筛选，获得一株能与３Ｈ１１特异反应的阳性克隆．其ｃＤＮＡ插入片段为５５４ｂｐ．ＧｅｎＢａｎｋ不含其同源序列．将此ｃＤＮＡ片段与谷胱甘肽转移酶表达质粒ｐＧＥＸ－４Ｔ重组，Ｗｅｓｔｅｒｎｂｌｏｔ和竞争抑制实验表明，表达产物依然保持同３Ｈ１１反应的特异性．可见它是３Ｈ１１对应抗原的ｃＤＮＡ．

Cloning of the cDNA Fragment of a Tumor Associated Antigen Recognized by Monoclonal Antibody 3H11

Monoclonal antibody (McAb) 3H11 can specifically bind to different tumor cells.Consequently cloning of the corresponding antigen is significant.The exprssion library,which was constructed with human gastric cancer cell line MGC 803,was screened with the McAb 3H11.One positive clone specifically recognized by McAb 3H11 was isolated.The cDNA fragment in the clone is 554 bp and there is no homology in GenBank.After recombination of this cDNA with Glutathione S transferase (GST) expression vector pGEX 4T,revealed by Western blot the GST fusion protein could react with McAb 3H11,but not with other antibodies.Moreover,the protein derived from the cDNA could competitively inhibit the binding between McAb 3H11 and MGC 803 cells.This work will be helpful to further research on the 3H11 tumor associated antigen.