Methods and compositions for insertion of antibody coding sequences into a safe harbor locus

A method for inserting an antibody coding sequence into the first intron of an albumin locus in one or more liver cells in a subject that is a human or non-human primate, comprising introducing into the one or more liver cells in subject:

• (a) a nuclease agent that targets a target site in the first intron of the albumin locus or one or more nucleic acids encoding the nuclease agent;
• and (b) an exogenous donor nucleic acid comprising the antibody coding sequence,
• wherein the nuclease agent cleaves the target site and the antibody coding sequence is inserted into the first intron of the albumin locus to produce a modified albumin locus,
• wherein the antibody is not a single-chain antibody,
• wherein the antibody comprises a heavy chain and a separate light chain,
• wherein a heavy chain coding sequence is upstream of a light chain coding sequence in the antibody coding sequence,
• wherein the heavy chain coding sequence comprises VH, DH, and JH segments, and the light chain coding sequence comprises VL and JL gene segments,
• wherein the heavy chain and the light chain are linked by a 2A peptide,
• wherein the 2A peptide is a T2A peptide,
• wherein a nucleic acid encoding a furin cleavage site is included between the heavy chain coding sequence and the light chain coding sequence, and wherein the furin cleavage site is included upstream of the 2A peptide,
• wherein the heavy chain coding sequence is operably linked to an endogenous albumin secretion signal sequence in the modified albumin locus, and the antibody coding sequence comprises an exogenous secretion signal sequence upstream of the light chain coding sequence,
• wherein the inserted antibody coding sequence is operably linked to an endogenous albumin promoter in the modified albumin locus, and
• wherein the antibody targets a disease-associated antigen.