Figure 3

Expression, purification, and antigen binding characteristics of SBU-CD55 × CD20. (a) Expression cassette for SBU-CD55 × CD20. Pink and white circles indicate a knob mutation (T366W) and hole mutations (T366S, L368A, and Y407), respectively. (b) Schematic illustration of the structure of SBU-CD55xCD20. (c) SDS-PAGE showing the purified SBU-CD55 × CD20, Lane 1: reduced SBU-CD55 × CD20; Lane 2: nonreduced SBU-CD55 × CD20. (d,e) ELISA to show the binding of SBU-CD55 × CD20 to CD55 (d) and CD20 (e). Antigen binding ELISA signals for SBU-CD20 were compared with those for monoclonal IgG antibodies (rituximab and 4-1H). Error bars indicate the standard error (SE) from duplicate runs of the same sample.