Peptide-antibody complexes, including fusions and conjugates, that target or accumulate in target cells, such as tumors and diseased cells, or enhance the immune system are disclosed. In some embodiments, such complexes function as platforms for attaching and targeting one or more therapeutic agents or detectable agents, including radioisotopes, detectable labels, and/or cytotoxic agents, to target cells in the central nervous system or across the blood brain barrier, cancerous cells, or target cells recognized by the antibody in such complexes. In some complexes, the peptide serves as the targeting mechanism, while other embodiments contemplate the antibody as the targeting mechanism. Peptides and/or antibodies can be engineered to deliver various effector functions in various embodiments. Peptide-antibody complexes that function as immunotherapies and enhance a body's immune system in detecting and/or destroying diseased cells or pathogens are also disclosed. Pharmaceutical compositions and uses of peptide-antibody complexes are further disclosed.
