Abstract: Objectives　Humanize the Frame regions in Variable regions of the murine monoclonal antibody against Alzheimer's disease, to establish a basis for clinic application in the future. Methods　Based on the chimeric antibody constructed previously, we humanized the frame regions of the heavy chain and the light chain in variable regions using template-replacement method. Eukaryotic expression vectors were got by inserting humanized antibody genes of the heavy and light chains into vectors. Then the eukaryotic expression vectors were co-transfected into CHO cells using liposome fusion method. The tests of characters include the titer and expression amount using ELISA, as well as molecular weight using SDS-PAGE and Western Blot and biological activity tested by immunohistochemistry. Results　The heavy chain of the recombinant antibody was about 1500bp and the light chain was about 750bp, which was in accordance with our anticipation. The expression amount of the product was 1.11mg/L. The molecular weight of the humanized antibody was about 51ku(heavy chain) and 25ku(light chain). The expressed product can bind Aβ antigen specifically tested by ELISA(A value of the humanized antibody: 2.24), keeping the same as that of the chimeric antibody basically. The expressed product can only be recognized by goat-anti-human antibody rather than goat-anti-mouse antibody. The results also showed the expressed product can bind Aβ antigen specifically tested by immunohistochemistry. Conclusions The humanized antibody keeps the same as the chimeric antibody in biological activity basically, this provides a possibility for its clinic application for Alzheimer's disease in the future.

Key words: Alzheimer’s disease, humanized antibody, chimeric antibody, β amyloid peptide