Abstract: Provided herein are anti-PD-1/LAG3 bispecific antibodies and antigen-binding fragments. Also provided here are methods and uses of these antibodies and antigen-binding fragments in the treatment of cancer or infectious disease.

Abstract: Provided herein are biparatopic antigen-binding constructs that specifically bind HER2. The biparatopic antigen-binding constructs comprise one antigen-binding moiety that binds to ECD2 of HER2, a second antigen-binding moiety that binds to ECD4 of HER2, and an Fc. At least one of the antigen-binding moieties is an scFv. The biparatopic antigen-binding constructs can be used in the treatment of cancer.

Abstract: Described herein are high affinity antigen binding constructs, e.g., antibodies, directed to the ECD2 domain of HER2. The antigen-binding constructs comprise at least one antigen-binding polypeptide construct that binds to ECD2 of HER2 (HER2 ECD2) with increased affinity compared to a wild-type 2C4 antibody. Such antigen-binding polypeptide constructs comprise one or more amino acid modifications in the framework region and/or CDRs compared to the amino acid sequence of a wild-type 2C4 antibody that increase affinity of the antigen-binding polypeptide construct for ECD2 by 2-fold or greater. The antigen-binding constructs can inhibit the growth of HER2-expressing breast cancer cells and gastric cancer cells. Antigen-binding constructs in biparatopic format are internalized in HER2-expressing cells.

Abstract: The provided scaffolds have heavy chains that are asymmetric in the various domains (e.g. CH2 and CH3) to accomplish selectivity between the various Fc receptors involved in modulating effector function, beyond those achievable with a natural homodimeric (symmetric) Fc molecule, and increased stability and purity of the resulting variant Fc heterodimers. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: Provided herein are biparatopic antigen-binding constructs that specifically bind HER2. The biparatopic antigen-binding constructs comprise one antigen-binding moiety that binds to ECD2 of HER2, a second antigen-binding moiety that binds to ECD4 of HER2, and an Fc. At least one of the antigen-binding moieties is an scFv. The biparatopic antigen-binding constructs can be used in the treatment of cancer.

Abstract: Provided herein are biparatopic antigen-binding constructs that specifically bind HER2. The biparatopic antigen-binding constructs comprise one antigen-binding moiety that binds to ECD2 of HER2, a second antigen-binding moiety that binds to ECD4 of HER2, and an Fc. At least one of the antigen-binding moieties is an scFv. The biparatopic antigen-binding constructs can be used in the treatment of cancer.

Abstract: Disclosed are the atomic coordinates of compositions comprising Fc heterodimer proteins in crystalline form derived from high resolution x-ray diffraction. Further disclosed are systems and methods for using all or a portion of these atomic coordinates to identify and design improved Fc heterodimer proteins. Further disclosed are compositions comprising a mixture of (i) a solubilized Fc heterodimer protein and (ii) a mother liquor solution. The mother liquor solution comprises between 2% and 10% (v/v) ethylene glycol, between 10% and 25% (w/v) polyethylene glycol having an average molecular weight of between 2000 Daltons and 10000 Daltons, and between 0.05 M and 0.40 M ammonium iodide. Further disclosed are systems and methods of identifying a mutation which promotes heterodimeric Fc chain pair formation in which structure based modeling is performed to identify a candidate mutation to an Fc chain using all or a portion of the disclosed three-dimensional atomic coordinates.

Abstract: Disclosed are the atomic coordinates of compositions comprising Fc heterodimer proteins in crystalline form derived from high resolution x-ray diffraction. Further disclosed are systems and methods for using all or a portion of these atomic coordinates to identify and design improved Fc heterodimer proteins. Further disclosed are compositions comprising a mixture of (i) a solubilized Fc heterodimer protein and (ii) a mother liquor solution. The mother liquor solution comprises between 2% and 10% (v/v) ethylene glycol, between 10% and 25% (w/v) polyethylene glycol having an average molecular weight of between 2000 Daltons and 10000 Daltons, and between 0.05 M and 0.40 M ammonium iodide. Further disclosed are systems and methods of identifying a mutation which promotes heterodimeric Fc chain pair formation in which structure based modeling is performed to identify a candidate mutation to an Fc chain using all or a portion of the disclosed three-dimensional atomic coordinates.

Abstract: The provided scaffolds have heavy chains that are asymmetric in the various domains (e.g. CH2 and CH3) to accomplish selectivity between the various Fc receptors involved in modulating effector function, beyond those achievable with a natural homodimeric (symmetric) Fc molecule, and increased stability and purity of the resulting variant Fc heterodimers. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: Disclosed are the atomic coordinates of compositions comprising Fc heterodimer proteins in crystalline form derived from high resolution x-ray diffraction. Further disclosed are systems and methods for using all or a portion of these atomic coordinates to identify and design improved Fc heterodimer proteins. Further disclosed are compositions comprising a mixture of (i) a solubilized Fc heterodimer protein and (ii) a mother liquor solution. The mother liquor solution comprises between 2% and 10% (v/v) ethylene glycol, between 10% and 25% (w/v) polyethylene glycol having an average molecular weight of between 2000 Daltons and 10000 Daltons, and between 0.05 M and 0.40 M ammonium iodide. Further disclosed are systems and methods of identifying a mutation which promotes heterodimeric Fc chain pair formation in which structure based modeling is performed to identify a candidate mutation to an Fc chain using all or a portion of the disclosed three-dimensional atomic coordinates.

Abstract: The provided scaffolds have heavy chains that are asymmetric in the various domains (e.g. CH2 and CH3) to accomplish selectivity between the various Fc receptors involved in modulating effector function, beyond those achievable with a natural homodimeric (symmetric) Fc molecule, and increased stability and purity of the resulting variant Fc heterodimers. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: The provided scaffolds have heavy chains that are asymmetric in the various domains (e.g. CH2 and CH3) to accomplish selectivity between the various Fc receptors involved in modulating effector function, beyond those achievable with a natural homodimeric (symmetric) Fc molecule, and increased stability and purity of the resulting variant Fc heterodimers. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: Provided herein are biparatopic antigen-binding constructs that specifically bind HER2. The biparatopic antigen-binding constructs comprise one antigen-binding moiety that binds to ECD2 of HER2, a second antigen-binding moiety that binds to ECD4 of HER2, and an Fc. At least one of the antigen-binding moieties is an scFv. The biparatopic antigen-binding constructs can be used in the treatment of cancer.

Abstract: Provided herein are isolated heteromultimers comprising: at least one single domain antigen-binding construct attached to at least one monomer of a heterodimer Fc region; wherein the heterodimer Fc region comprises a variant CH3 domain comprising amino acid mutations that promote the formation of said heterodimer with stability comparable to that of a native Fc homodimer; and wherein said isolated heteromultimer is devoid of immunoglobulin light chains and optionally devoid of immunoglobulin CH1 region. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: Rationally designed antibodies and polypeptides that comprise multiple Fc region amino acid substitutions that synergistically provide enhanced selectivity and binding affinity to a target Fc receptor are provided. The polypeptides are mutated at multiple positions to make them more effective when incorporated in antibody therapeutics than those having wild-type Fc components.

Abstract: Provided herein are heteromultimer constructs with reduced or silenced effector function. In an embodiment is provided a heteromultimer construct comprising an IgG Fc construct having a first and a second Fc polypeptide, each Fc polypeptide comprising a modified lower hinge region wherein: the modified lower hinge region of said first Fc polypeptide comprises at least one amino acid modification, the modified lower hinge region of said second Fc polypeptide comprises at least one amino acid modification which is different from at least one amino acid modification of said first Fc polypeptide, and the IgG Fc construct displays reduced binding to all Fc? receptors and to C1q protein as compared to a corresponding parent IgG Fc construct. Also provided are methods of producing such heteromultimer constructs, and methods of reducing ADCC for an antibody construct by reducing effector function.

Abstract: Rationally designed antibodies and polypeptides that comprise multiple Fc region amino acid substitutions that synergistically provide enhanced selectivity and binding affinity to a target Fc receptor are provided. The polypeptides are mutated at multiple positions to make them more effective when incorporated in antibody therapeutics than those having wild-type Fc components.

Abstract: Disclosed are the atomic coordinates of compositions comprising Fc heterodimer proteins in crystalline form derived from high resolution x-ray diffraction. Further disclosed are systems and methods for using all or a portion of these atomic coordinates to identify and design improved Fc heterodimer proteins. Further disclosed are compositions comprising a mixture of (i) a solubilized Fc heterodimer protein and (ii) a mother liquor solution. The mother liquor solution comprises between 2% and 10% (v/v) ethylene glycol, between 10% and 25% (w/v) polyethylene glycol having an average molecular weight of between 2000 Daltons and 10000 Daltons, and between 0.05 M and 0.40 M ammonium iodide. Further disclosed are systems and methods of identifying a mutation which promotes heterodimeric Fc chain pair formation in which structure based modeling is performed to identify a candidate mutation to an Fc chain using all or a portion of the disclosed three-dimensional atomic coordinates.

Abstract: Provided herein are isolated heteromultimers comprising: at least one single domain antigen-binding construct attached to at least one monomer of a heterodimer Fc region; wherein the heterodimer Fc region comprises a variant CH3 domain comprising amino acid mutations that promote the formation of said heterodimer with stability comparable to that of a native Fc homodimer; and wherein said isolated heteromultimer is devoid of immunoglobulin light chains and optionally devoid of immunoglobulin CH1 region. These novel molecules comprise complexes of heterogeneous components designed to alter the natural way antibodies behave and that find use in therapeutics.

Abstract: Rationally designed antibodies and polypeptides that comprise two Fc region amino acid substitutions that synergistically provide enhanced selectivity and binding affinity to a target Fc receptor are provided. The polypeptides comprise Fc region mutations at two positions that synergistically make the polypeptides more effective when incorporated in antibody therapeutics than those having wild-type Fc components.