Design, synthesis, and characterization of mononuclear antibody mimics

We designed mimics of rituximab, a monoclonal antibody (mAb) used to treat some lymphomas, for which CD20 antigen is well-known. For this purpose, selective aptamers of the CD20 antigen were selected by the SELEX (Systematic Evolution of Ligands by EXponential enrichment) method coupled with capillary electrophoresis (CE). After their characterization by isothermal titration calorimetric, the sequences were optimized in order to reduce their molecular weights. The most refined compounds were studied through biological experiments to validate the specificity of aptamer derivatives, from cells expressing or not the CD20 antigen. Two aptamers were selected, and dimeric constructions were performed by chemoselective ligations. These compounds should allow an increase in affinity towards the targeted cells.