Figure 2

Isolation of bispecific antibody by selective Protein A affinity chromatograpy.
(a) Chromatogram illustrating the separation of REGN2280 bispecific from the binding (FcFc) and non-binding (Fc*Fc*) homodimers, using a recombinant Protein A resin. The dotted trace shows pH and the solid trace shows the absorbance at 280 nm of load, wash and gradient elution steps. (b,c) Flow-cytometric analysis of CD20xCD3 bispecific antibodies REGN2280 and REGN1979 binding to CD20+/CD3− Raji (b) and CD3+/CD20− Jurkat (c) cells. Bound antibody is proportional to mean fluorescence intensity (MFI). A non-specific hIgG1 isotype control antibody showed no binding to either cell line.