[Construction of 3D model of CD28 chimeric antibody with its antigen docked].

Aim: To construct a 3D model of the chimeric antibodies (AntiCD28: ch-2F5) with corresponding antigen molecule docked to theoretically verify the rationality of the binding of antibody with its antigen and to provide a method of 3D identification between antigen and antibody and spatial structure analysis.

Methods: We analyzed the sequence by submitting it to http://www.ncbi.nlm.nih.gov/ and made a comparison using integratly the 3 databases of GenBank, Protein data bank and GENO-3D. The 3D model was constructed by Swiss-model homology modeling server and molecular docking online was performed by GRAMM-X Protein Docking Web Server. Chimeric heavy chain, light chain, heavy-light chain complex, heavy-light chain and antigen complex were displayed and photographed by the Chimera Software. Meanwhile, the spatial structures of heavy, light chains, variable region, constant region, CDR and frame area were marked by different colours respectively to exhibit the 3D structure on every side.

Results: The 3D structure of the heavy-light chain and antigen complex we constructed was consistent well with the theory of antigen binding to antibody molecules.

Conclusion: The structure of the chimeric antibody we constructed with the bioinformatic method was in accordance with the general structure of antibody, and its antigen binding site was also consistent with the molecular theory. Thus, the model helps to analyze the 3D structure of antibody and antigen-antibody interaction.