Method for the selection and production of tailor-made, selective and multi-specific therapeutic molecules comprising at least two different targeting entities and uses thereof

Herein is reported a method for determining a combination of antigen binding sites comprising the steps of (i) determining the binding specificity and/or affinity and/or effector function and/or in vivo half-life of a multitude of bispecific antibodies prepared by combining each member of a first multitude of antibody Fab fragments or scFv antibody fragments with each member of a second multitude of antibody Fab fragments or scFv antibody fragments, and a linker comprising at one of its termini the second member of the first binding pair and at the respective other terminus the second member of the second binding pair, whereby the first multitude specifically binds to a first cell surface molecule and the second multitude specifically binds to a second cell surface molecule, and (ii) choosing the bispecific antibody with suitable binding specificity and/or affinity and/or effector function and/or in vivo half-life and thereby determining a combination of antigen binding sites.