Abstract: A method can include determining a donor-specific human leukocyte antigen of a tissue transplant recipient; determining a ratio of the tissue transplant recipient for a level of an immunoglobulin G subclass 4 antibody (G4) for the antigen with respect to a level of another immunoglobulin G subclass antibody for the antigen; and, based on the ratio, deciding to administer an amount of the G4 to the tissue transplant recipient.

Abstract: A method can include administering a donor-specific human leukocyte antigen antibody to a tissue transplant recipient where the antibody is an immunoglobulin G subclass 4 antibody (G4). Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.

Abstract: Vector compositions and methods are provided for transfecting donor cell populations and tissues for grafts, for reducing expression of mismatched proteins, thereby reducing immunogenicity of the grafted cells and tissues in a recipient subject.