Screening The Specific Mimic Peptide With Higher Affinity To SMMC-7721 And Constructing Of Recombination Protein

As one of malignant tumors,Hepatocellular Carcinoma(HCC) is a common and fatal tumor.The present main therapy is removal by operation and chemotherapy,which can bring the remission of patients' condition and prolong of life,but the effect is not satisfactory.On the drug therapy aspect,some antibody drugs have carried out on clinical stage for antibody virtues of little side-effect,higher activity and long role time,et al.However, for themselives drawbacks and sources the drugs' usage is not widespread. A new prospect on diagnosis and therapy of tumor is developing because of genetic engineering antibody's production. For small molecular antibody, low immunity,easily penerating the targeted tissues, little side-effects,coupling with other effective molecules structuring new functional moleculars,such as bispecifics Ab and designing immunotoxin.The research has been developing through Single Chain Fv.single-domain antibody,indepentent variable region of heavy chain and minimal recognition unit.However,comparing with parental antibody,the genetic engineering antibody has the low affinity to antigen,so it is urgent to excerpt a suitable treatment plan and find a specific drug.Screening mimic peptide of antibody from polypeptides library is a wholly new thought of targeted therapy, which has shown an obvious technics superiority. We try to find a specific peptide, which has a high affinity to SMMC-7721 from 12-mer peptide library and circular 7-mer peptide library. The peptide can prove some useful help to therapy of HCC.First Screening the specific peptide: taking SMMC-7721 as the targeted molecules to biopan from peptide library in order to have phage rich,we can obtain the specific peptide.The negative control is normal hepatocyte.Getting positive clones and sequencing.Second Construction of Prokaryotic expression vector and protein purficiation.Wehave constructed a mutant of TSST-1 by protein engineering methods,which lost the ability to attach the MHC-II in order to reduce toxicity and ill effect,retainned the activity of stimulating cell factors of T cell.Through crosslinking the specific peptide and the gene of TSST-1,we got the recombination plasmid.After the purfication of targeted protein has been finished,we evaluated protein's activity by killing and wounding assay.Now we can firmly say that we have got the specific peptide which has high affinity to SMMC-7721,and obtained the protein of recombination.All prove many useful help to immune therapy of HCC.