Abstract: Bivalent antibody constructs comprising (a) a first polypeptide chain comprising a VL sequence, a CH3 sequence, a CH2 sequence, and a CH3 sequence, arranged from N- to C-terminus in a VL-CH3-CH2-CH3 orientation; (b) a second polypeptide chain comprising a VH sequence and a CH3 sequence, arranged from N- to C-terminus in a VH-CH3 orientation; (c) a third polypeptide chain comprising a VL sequence, a CL sequence, an antibody CH2 sequence, and a CH3 sequence, arranged from N- to C-terminus in a VL-CL-CH2-CH3 orientation; (d) a fourth polypeptide chain comprising a VH sequence and a CH1 sequence, arranged from N- to C-terminus in a VH-CH1 orientation; wherein the amino acid sequences of the C-terminal CH3 domains in the first and third polypeptide chains are different from one another and comprise complementary knob-in-hole mutations, and pharmaceutical compositions comprising the antibody constructs, and methods of use thereof are provided.

Abstract: Methods for screening libraries of polypeptides for biologically activity on cells. For example, polypeptides can be synthesized and encapsulated along with their coding sequences in microcapsules of an emulsion. Emulsion microcapsules can then be fused with microcapsules comprising test cells and biological activity on the cells is assessed to identify biologically active polypeptides and nucleic acid molecules encoding the same.

Abstract: Methods for screening libraries of polypeptides for biologically activity on cells. For example, polypeptides can be synthesized and encapsulated along with their coding sequences in microcapsules of an emulsion. Emulsion microcapsules can then be fused with microcapsules comprising test cells and biological activity on the cells is assessed to identify biologically active polypeptides and nucleic acid molecules encoding the same.