Abstract: Provided herein are antibodies, recombinant proteins, and methods of use thereof including, for example, immunoglobulin G (IgG) antibodies and recombinant proteins including a Fab region and an Fc region connected through a hinge region, where the hinge region is resistant to cleavage by a protease. Also, provided herein, inter alia, are immunoglobulin G (IgG) antibodies and recombinant proteins including a Fab region and an Fc region connected through a hinge region, and where the Fc region has higher affinity for a ligand compared to a wildtype Fc.

Abstract: In certain embodiments, described herein is a method of treating a subject infected with a pathogen encoding an Fc-binding protein comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising an Fc region of an immunoglobulin G antibody. Also described herein is a method for treating cancer in a subject undergoing oncolytic viral therapy comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising an Fc region of an immunoglobulin G antibody. Further described herein is a method of activating natural killer (NK) cells in a subject infected with a pathogen, comprising administering to the subject a pharmaceutical composition comprising an Fc region of an immunoglobulin G antibody.

Abstract: Disclosed herein are methods, reagents, and pharmaceutical compositions for modulating immune effector cell activation that does not require an antigen-specific antibody. The IgG Fc region is shown herein to contain both a domain that binds an Fc?R on immune effector cells and a non-overlapping region or domain that can bind Fc binding proteins on target cells, and that it is capable of bridging immune effector cells and target cells expressing Fc binding proteins without use of the antigen-binding region (Fab) of the antibody. Therefore, also disclosed are methods of enhancing or inhibiting passive ADCC in subjects.