Screening Of MUC1 Mimotope In T7 Phage Library Of Lung Cancer

Background: Lung cancer is one of the most frequent malignant tumors, its morbidity and mortality rates remain number one among all cancers. Due to lack of early detection and advanced treatment methods, about 80% of lung cancer patients had been found in late stages, and missed the best timing of treatments. Their five-year survival rate is less than 15%. Tumor-specific vaccine has been becoming an emerging cancer treatment method in recent years. The peptide tumor vaccine composition is simple and easy to obtain. Mimotope peptide has low molecular weight that mimics of the natural antigen. Its conformation is highly similar to natural antigen and can induce specific humoral and cellular immunity as a natural antigen does. Phage display system is widely used in studies of screening mimotopes because of its large capacity, small volume, and amplifying. In this experiment, we biopanned a lung cancer T7 phage library using two monoclonal antibodies of MUC1 as molecular targets to identify the corresponding mimotopes. These mimotopes are then evaluated for their specificities and clinical values.Methods: 1. A lung cancer T7 phage library was biopanned using MUC1 monoclonal antibodies as molecular targets respectively, and then amplified to obtain positive clones; 2. The positive phage clones were acquired, plated and titered, then amplified; 3. Positive phage clones were sequenced and identify their amino acid sequences; 4. These positive phage clones were tested as dose-dependent affinity for lung cancer-specificity; 5. Results were analyzed and identities were determined.Results: 1. Phage library was successfully amplified and tittered. After amplification the titer was 7×1010pfu/m L and the capacity was 1.85×106pfu/m L. 2. After biopanning with the MUC1 monoclonal antibody as the target molecule, 20 positive phage clones were obtained. We got two amino acid sequence of AAPDFRP and SAPDDRP, which inhibition rates to the MUC1 monoclonal antibody were above 50%, moreover, these clones showed significantly higher serum binding specificity in lung cancer patients than that in healthy human(P<0.05). It is considered that these two protein sequences can be used to simulate the MUC1 epitopes for immunoreaction to a certain extent. 3. Simulated the tertiary structure of the two polypeptide sequences.Conclusions: Biopanning a T7 phage library of lung cancer successfully obtained two mimotopes polypeptide sequences which could simulate the biological function of the antigen MUC1. Mimotope of antigen MUC1 enriched the types of vaccine of lung cancer and provided a novel diagnostic method, and laid a foundation for the treatment of lung cancer.