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目的用具交叉保护性的针对类脂 A的单抗 (1B6 )筛选噬菌体十五肽库 ,旨在研究类脂 A的模拟肽。方法对噬菌体十五肽库进行亲合筛选 ,用噬菌体 EL ISA法鉴定阳性克隆。结果经 3轮筛选后 ,随机挑选 14个噬菌体克隆 ,做夹心EL ISA试验 ,其中 5个克隆显示较强的阳性结果。将上述 5个阳性克隆 DNA测序 ,序列均为 ACTCATTGGCATCAGTGGAGGCATCATCAGTTTCCTGCTCCTACT,相应的氨基酸序列为 THSHQWRHHQFPAPT。竞争性噬菌体 EL ISA的结果显示大肠杆菌 L PS和伤寒杆菌 L PS均可特异性抑制阳性噬菌体克隆与类脂 A抗体的结合。结论该噬菌体克隆展示肽具有 L PS表位的抗原性 ,且模拟了 L PS的共同部分类脂 A。
OBJECTIVE: To screen a phage-pentadeptide library using a cross-protective monoclonal antibody directed against lipid A (1B6) to study the lipid peptide analogs. Methods The phage 15 peptide library was screened by affinity, and the positive clones were identified by phage ELISA. Results After 3 rounds of screening, 14 phage clones were randomly selected for sandwich ELISA. Five of the clones showed strong positive results. The above 5 positive clones were sequenced. The sequences were all ACTCATTGGCATCAGTGGAGGCATCATCAGTTTCCTGCTCCTACT and the corresponding amino acid sequence was THSHQWRHHQFPAPT. The results of the competitive phage EL ISA showed that both E. coli L PS and S. typhimurium L PS specifically inhibited the binding of positive phage clones to the lipid A antibodies. Conclusion This phage cloned display peptide has the antigenicity of the L PS epitope and mimics the lipid A common to L PS.