Objective       To construct a mouse-human chimeric anti-mucin1 (MUC1) IgG antibody with decreased immunogenicity of mouse anti-MUC1 monoclonal antibody (mAb)-6E3 in human

and to characterize the binding property of mammalian cell-produced mouse-human chimeric anti-MUC1 IgG antibody.       Methods       The variable region genes of mouse mAb-6E3 were amplified by PCR and were inserted into a human IgG mammalian expression vector through corresponding restriction enzyme sites. 293T mammalian cells were transiently transfected with the recomb

inant chimeric IgG expression plasmid

and the intracellular IgG antibody expression was confirmed by immunofluorescence test. The chimeric anti-MUC1 IgG antibody was purified from cell supernatants by affinity chromatography

and was characterized by SDS-PAGE electrophoresis. Its binding activity with denatured and natural MUC1 antigen was analyzed by Western blotting and flow cytometry

and the binding affinity was determined by surface plasmon resonance technology.       Results       A mouse-human chimeric anti-MUC1 IgG antibody was obtained by fusion of mouse monoclonal antibody variable region with human IgG constant region. The obtained chimeric IgG antibody could specifically bind to natural and denatured MUC1 on the surface of T47D tumor cells

with binding affinity of 2.8×10

-7

M.        Conclusion       A functional chimeric anti-MUC1 IgG is obtained successfully

and it can bind to tumor-associated MUC1 specifically.