Disclosed herein are antibody fusion constructs and uses thereof. The antibody fusion construct may comprise an antibody fusion protein. The antibody fusion protein may comprise a non-antibody peptide inserted into an antibody portion of the antibody fusion protein. Alternatively, the antibody fusion construct may comprise a bispecific antibody. The bispecific antibody may comprise a second antibody or antibody fragment inserted into a first antibody or antibody fragment. Insertion of the non-antibody peptide (or second antibody or antibody fragment) into the antibody portion (or first antibody or antibody fragment) may comprise replacement of one or more amino acids in a constant domain of the antibody portion (or first antibody or antibody fragment). The antibody fusion constructs disclosed herein may be used to treat a disease, such as a cancer, an autoimmune disorder or an infection.
