Abstract: Methods and compositions to treat or prevent infections by respiratory virus, including SARS-CoV-2 (COVID-19). Included are chimeric antibodies comprising an immunoglobin region having an Fc domain that does not bind Fc?Rs and/or C1q, e.g. having substitutions L234S, L235T, G236R (STR), and an ACE2 domain having high affinity binding to a plurality of viral variants, e.g. having substitutions T27L or T27Y, H34V, N90E (LVE or YVE). The antibodies may have increased binding to FcRn, e.g. having substitutions M252Y, S254T, and T256E (YTE). The antibodies can be administered intranasally, by respiratory nebulization or systemically to treat or prevent respiratory viral infections.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, as well as methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation in viral infection, I are described. For example, polypeptides and other compounds can be used to inhibit immune complex formation in a subject who has been diagnosed as having or is suspected of having an Ebola virus infection, a subject who has been diagnosed as having or is suspected of having an influenza virus infection, or a subject who has been diagnosed as having or is suspected of having a hepatitis virus infection.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, Immune complexed IgG to IgG F?R binding, and immune complexed IgG mC1q (membrane C1q) or soluble C1q binding. Such compounds may have therapeutic use in treating amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, as well as methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation in viral infection, are described. For example, polypeptides and other compounds can be used to inhibit binding of DF-associated, immune-complexed IgG anti-DF viron(s) or DV viral antigens to F?R, ADE of DF/DHF/DSS infections by inhibition of DF viral antigen binding to immune complexed IgG, F?R and immune complexed IgG mC1q (membrane C1q) or soluble C1q binding.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, Immune complexed IgG to IgG F?R binding, and immune complexed IgG mC1q (membrane C1q) or soluble C1q binding. Such compounds may have therapeutic use in treating amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation in autoimmune/immune thrombocytopenia.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation in viral infection. For example, polypeptides and other compounds can be used to inhibit binding of DF-associated, immune-complexed IgG anti-DF viron(s) or DV viral antigens to F?R, ADE of DF/DHF/DSS infections by inhibition of DF viral antigen binding to immune complexed IgG, F?R and immune complexed IgG mC1q (membrane C1q) or soluble C1q binding.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, Immune complexed IgG to IgG F?R binding, and immune complexed IgG mC1q (membrane C1q) or soluble C1q binding. Such compounds may have therapeutic use in treating amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, immune complexed IgG binding to IgG F?R, and immune complexed IgG binding to mC1q (membrane C1q) or soluble C1q. The polypeptides and compounds provided herein can have therapeutic use in treating Alzheimer's disease (AD).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, immune complexed IgG binding to IgG F?R, and immune complexed IgG binding to mC1q (membrane C1q) or soluble C1q. The polypeptides and compounds provided herein can have therapeutic use in treating Parkinson's disease (PD).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, immune complexed IgG binding to IgG F?R, and immune complexed IgG binding to mC1q (membrane C1q) or soluble C1q. The polypeptides and compounds provided herein can have therapeutic use in treating amyotrophic lateral sclerosis (ALS).

Abstract: Polypeptides and other compounds that can bind specifically to the CH2-CH3 cleft of an immunoglobulin molecule, and methods for using such polypeptides and compounds to inhibit Fc-mediated immune complex formation, are described.