Identification of epitope recognized by mAb 15 A11 sepecific against cartilage oli-gomeric matrix protein / 中国免疫学杂志

ABSTRACT

Objective:To identify the epitope of mAb15A11 which is specific against RA associated autoantigen cartilage oligomeric matrix protein ( COMP ).Methods: A filamentous phage library displaying random linear dodecapeptides was used to mapping the epitope of mAb15A11.After three rounds of screenings,40 phage clones were selected at random and sequenced.The specificity of phages was confirmed by enzyme immunoassays.Homology search by ClustalW2 and structure analysis by PyMol to identified the epitope amino acid sequence.Western blot analysis of COMP and ELISA analysis of COMP-derived peptides were used to confirm epitope′s characterization.Results: After repeated screenings using bio-panning method, 2 clones were identified, which interacted specifically with mAb 15A11.Homology search did not find succession consensus sequence within COMP molecular,which indicated that the epitope was not linear.PyMol Structure analysis identified the rationality of conformational epitope.Western blot analysis and ELISA of EDTA-treated COMP further prove an conformational structure of the epitope recognized by mAb 15A11.ELISA analysis of COMP-derived peptides demonstrated both disulfide bonds between 229 C-243 C and 237 C-253 C and every epitope amino acid of 232 G,238 H,240 H,241 A,244 V,247 R and 251 R were essential to the binding of mAb 15A11 with COMP.Conclusion: In this study, the potential B cell antigentic epitopes of mAb 15A11 was identified by phage display library.The epitope amino acids sequence and char-acterization were also recognized.It may have important theoretical value for the study of reaction mechanism of COMP antibody and antigen and may also show application significance in the detection of rheumatoid arthritis.