Experimental Research Of Screening Biomarkers In The Sera Of Npc With Phage Random Peptide Library

Background and Objective: Nasopharyngeal Carcinoma(NPC) is a kind of polygenic inheritance disease . At present the diagnosis of NPC is mainly by biopsy, because of its early symptoms are not obvious, the 5-year survival rate of the patients is only 50%. However, tumor patient body can produce corresponding tumour marker has been confirmed. We can diagnose early NPC patients by examining these tumor marker. In order to provide new method for the diagnosis of earlier NPC, we can use molecular biology and immunological methods to find those sensitivity and specificity of relatively high tumour marker.Phage display technique(PDT) is a intensive biotechnology for selecting polypeptides or proteins of specific combination, Its the biggest advantage is directly associate presented phenotypes with their genotype together.The displayed exogenous protein keep their relatively independent spatial structure and biological activity,and we obtain the interested proteins or peptide by using its ligands specificity affinity,then the peptide can be sequenced to obtain the corresponding information,such as the structure and the function. So we use the technology to select the specific tumor antigen of NPC patients and expect to obtain new markers with the diagnosis and prognosis of NPC patients. Methods:1.We used the normal serum and NPC patients'serum to Coat the microporous plate separately. With the increasing intensity screening methods, through the preadsorption with the normal serum, the noncombination phage were adsorbed with the serum of NPC patients. Then the phage combined with the serum of NPC were proliferated.The positive clones were obtained through three rounds of biopanning. 2.The reactivity of each clone bound to the serum of NPC patients was examined by ELISA. The phages significantly were picked out and Tested again with expanding serum samples. Finally,we got the clones could bind to the serum of NPC patients;3. The DNA of positive phage clones are extracted , purified,and sequenceed with -96â…¢primers. Then,we obtained the peptides Sequences from DNA sequence deduction,Results:The eluted phages were enriched nearly to 100 fold through three rounds of biopanning. From the clones selected randomly after the third round biopanning we got 2 specific clones to NPC serum ;2. The two peptide sequence were conformed by sequencing;3.The identification of two phage cloning showed no significant difference between the serum of IgA(VCA)-negative and IgA(VCA)-positive by ELISA appraisal;4. The two phage cloning were respectively identified in the serum of NPC, liver, ovarian cancer by ELISA, which result showed that the two phage cloning had the specific binding in serum of NPC.Conclusion:The peptides from immunoscreening of phage random peptide library may provides candidate biomarkers for early diagnosis, united detection and immunization therapy of NPC.