Antibodies are an important class of biomolecules that have contributed immensely to several fields including, medicine, diagnostics, and as an important biomolecule required for a plethora of scientific procedures. However, methods to control antibody-antigen binding using exogenous stimuli such as light remain limited. The use of antibodies in a therapeutic setting has become a dominant biological platform in the pharmaceutical market and has been successfully employed for the treatment of numerous diseases including autoimmune disorders, cancers, infections, and cardiovascular diseases.
Cancer immunotherapeutics are often developed to target overexpressed antigens near tumour cells or on the surface of malignant cells. Often these disease targets are essential biological receptors that have developed mutations affecting expression levels or activity. Although highly expressed on targeted tumour cells, basal levels of targeted receptors can be present on healthy cells. Consequently, the reduced specificity of antigen targeting between healthy and diseased cells can cause severe side-effects of antibody therapeutics. By introducing methods to enable the spatiotemporal control of antibody-antigen binding affinities by light, an additional level of safety and improved targeting is achieved for these therapeutic molecules.
The research performed in this thesis aimed to explore strategies and available technologies for the site-specific incorporation of designer amino acids with unique chemistries that could facilitate the spatiotemporal control over antibody-antigen binding with the use of external stimuli. A simple and robust method was designed for the genetic incorporation of photocaged tyrosine (pcY) into the structure of an anti-EGFR antibody fragment, 7D12. Subsequent techniques developed to evaluate light-mediated binding of 7D12 mutants to its target on the surface of cancer cells demonstrated binding inhibition with the presence of pcY in two positions, Y32pcY and Y113pcY and upon irradiation with 365 nm light and de-caging of pcY, binding was restored
