用随机6肽库筛选HGVE2抗原表位

Biopanning of HGV E2 Antigen Epitope from a Phage-displayed Random 6 Peptides Library *

利用抗 HGV E2区的 3株单克隆抗体 M6、M1 3、M30作为筛选配基 ,对随机 6肽库进行亲和筛选 . 3轮筛选的投入产出比逐轮升高至 3.5× 1 0 -3、假阳性率逐轮降低至 0 .4% ,提示具有良好的富集效果 .从第 3轮随机挑出 1 2个克隆进行功能鉴定 ,结果表明 8个克隆与 M6抗体有较强的特异性结合力并有较好的竞争抑制作用 ,测序发现它们的外源肽具有核心序列 :WA( W/Y) WXH,该序列与 HGV同源性低 ;用外源肽与核心序列相似的噬菌体克隆 P6GC9做竞争抑制试验 ,约 3×1 0 10个噬菌体即可较好地抑制 M6单抗与 HGV抗原结合 .该多肽可能是 HGV E2区识别 M6单抗并具有一定功能的模拟表位 .

Three mouse monoclonal antibodies(mAb) specific for the human hepatitis G virus E2 antigen were used to bio pan a random peptide library of 6 amino acid residues displayed as a fusion to protein Ⅲ of filamentous phage fd.In 3 rounds of screening,the gradual increase of the ratio of output to input and the gradual decrease of the false positive rate were 3.5×10 -3 and 0.4% respectively,which means that the enrichment is very effective.After the third round of screening,12 clones were selected and used in binding test and competetive inhibition test.Eight out of the 12 clones could specifically bind to mAb M6,while the inhibition rate of 8 clones was beyond 60%.Deduced from the foreign sequence inserted in the coat protein gene,all clones had the core sequence—WA(W/Y)WXH.P6GC9 whose foreign peptide shares WA(W/Y)WXH motif could competitively inhibit M6 binding to HGV E2.All this means that WA(W/Y)WXH has potent antigenicity.Peptide P6GC9 could be further explored for usage in anti viral vaccintion and diagnosis,and used as a clinical medicine.