How do biologics drive antibody-directed targeting?
Antibody-antigen interactions are dependent on a lock-and-key mechanism - and antibody binding regions are specifically configured to exhibit selective affinity to one antigen alone. This system is used by the immune system to mark both foreign pathogens and one’s own cells which have become infected or exhibit abnormalities. Antibody-directed targeting can be used to help direct cells into specific environmental niches and encourage certain cell-cell interactions. Antibodies can also be used as vectors, carrying drugs, other biologics, or tracers to cells of interest.
From a clinical perspective, antibody-directed targeting has applied in research of autoimmune diseases (using antibodies to decrease immune cell activity) and neurodegenerative diseases (targeting and marking β-amyloid for cell-mediated clearance). However, it features most prominently in cancer research. Immune evasion is a key factor in cancer cell survival, proliferation, and metastasis, and occurs because cancer cells downregulate the antigens normally detected by the immune system. To counter this, researchers are researching and developing customized antibodies targeting antigens which are selective to cancer cells and also ubiquitously expressed. Immune cells can then home in on the antibody – which is recognized as foreign – and destroy the cancer cell.