Decoupling Functional Pleiotropy of Interferon gamma with Protein Engineering

Interferon gamma (IFNg) plays a crucial role in the immune system by activating immune cells like macrophages and T cells, enhancing their ability to fight infections and tumours, and helping to control cancer progression by promoting immune responses against cancer cells. However, this cytokine has achieved minimal therapeutic utility due to its toxicity and pleiotropic activities.
The project aims to target IFNg to cells expressing PD-L1, an immunosuppressive molecule expressed on the cell surface of some cancer cells. To achieve targeted delivery, a single-chain fusion protein is to be created linking mutated IFNg monomers and a PD-L1 nanobody. Mutating several residues at the receptor binding interface prevents this cytokine from binding cells without first binding of the targeting nanobody therefore reducing systemic toxicity. We believe that these variants will decouple the immune stimulant from immunosuppressive IFN activities and will represent a more attractive agonist to translate this cytokine into an efficient and safe therapy.
The project also involves creating surrogate cytokines, novel molecules utilizing nanobodies against the IFNg receptors capable of dimerizing the receptors to induce IFNg signalling. This aims to help patients who generate antibodies against the IFNg cytokine which hinders their immune system causing recurring infection.