Figure 1.

Schematic representation of a bispecific pH-responsive anti-CEACAM5 antibody that binds pH-independently CEACAM6. (A) Illustration of the bispecific SEEDbody as a recycling body in the periphery. The antibody together with its antigen is internalized by pinocytosis. In the acidic conditions of the endosome, the antibody releases CEACAM5 (blue) due to the pH-shift and gets recycled by the neonatal Fc receptor (orange). The antigen is degraded in the lysosome. (B) Depiction of the binding behavior of CEACAM5/CEACAM6 bispecific antibodies. The CEACAM5-specific heavy chain (CH1 and VH illustrated in blue) is binding to shed CEACAM5 (blue boxes). The CEACAM5-attached GPI anchor is depicted as a small box on the tumor cell surface in light blue. The CEACAM6-specific CH1-VH are depicted in red/orange and solely bind to the tumor surface attached CEACAM6 (depicted in violet, GPI-anchor in light violet).