| Objective: This topic is to search for the squence of short active peptide with bindingto human CD59 and a short-peptide clamp which can bide with CD59 specificitily, Wewant to use this short-peptide clamp to block or trouble the express of CD59, it canprovide a base of immunotherapy of tumor.Methods: Taking the protein of cell disruption of Hela cells and the CHO cellsprotein by ion-exchange chromatography as target cells, a five-round affinity screeningwas done randomly through the Ph.D.-12 phage display library. Pick out random phagemonoclones for sequencing from peptide libraries screened, and analyze the monoclones'specific binding efficiency compare with the wild type phage VcsM13, The DNA ofphages were extracted, sequenced and translated to the sequences of amino acid andcompared with the international protein database. From the sequence results, find thepeptides having high consistency. Using this high homology sequence of amino acid tosynthesize short-peptide clamp and detecting.Results: After five rounds of binding-eluting-amplifying-rebinding's biopanning, thedisplayed peptide phages have high specificity and strong affinity for their cognate celltypes relative to wild type phage VcsM13 and different cell lines. The quantity of outputphages can reach 10~7～10~8 of the cell surface-bound phages. Through sequencing, weget one sequence of displayed peptides of Hela. The sequence is-ACHWPWCHGC-,Whereas, CHO has two: -ACHWWHAWTC-, -ACWWFHPHLC-. Comparing thesesequences we chose the higher homology sequence of Hela to synthesize the short-peptide clamp.Conclusions: We obtained the sequence of peptide with binding to CD59 throughrandom phage peptide library. These obtained targeted mimicry peptides maybe theepitopes in ligand proteins that be able to bind specially and tightly with some receptorson tumor cell's surface, The short-peptide clamp has the conspicuous seal effect onhuman CD59 by interaction with Hela cells.
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