Design and evolution of deimmunized protein superglues to enhance modular cell therapy

The generation of novel therapeutics often depends on improved tools to bridge and combine biological building-blocks. We have developed a simple and efficient route to link peptides and proteins in living systems, a kind of protein superglue. This route depends on a surface protein originally derived from the bacterium Streptococcus pyogenes. This superglue technology has reached the clinic for vaccines and is moving towards the clinic for anti-cancer therapeutics. However, most of the world experiences mild infection by this bacterium and generates antibodies that recognise the bacterium's surface proteins. Such an immune response is a major obstacle to the success of this protein superglue for new therapies. Here we will develop variants of our protein superglue that are minimally recognised by the human immune system. We will then make use of our re-engineered superglue towards an important challenge for cell-based therapies. CAR-T cells have become a highly successful therapy for cancers of B cells. However, CAR-T cell therapy has not been successful against cancers of T cells. We will apply our protein superglue to address limiting factors for CAR-T cells against T cell cancers. We will establish control over the extent and time-course of CAR-T cell activation against T cell lymphoma cells, which is important to avoid sometimes fatal immune over-activation. Using the re-engineered superglue, we will also establish the efficient targeting of the CAR-T cells against cell-surface markers that are specific to the cancer and not all T cells, which is key for avoiding dangerous immunodeficiency.

Simple efficient reactions for connecting biological building-blocks open up many new therapeutic possibilities. We have designed SpyTag, a peptide which forms an unbreakable isopeptide bond upon encountering its protein partner SpyCatcher. SpyTag has enabled diverse applications, including rapid assembly of potent vaccine candidates, multiplexed functionalization of antibodies, and precision targeting of gene therapy. SpyTag/SpyCatcher is derived from Streptococcus pyogenes and we have shown that it is common for people to express antibodies that recognise this pair. Such an immune response will limit the efficacy of therapies containing SpyTag/SpyCatcher. Here we will employ library-based selection and computational design to reduce both pre-existing antibody responses and induction of novel immune responses against SpyTag/SpyCatcher. This deimmunized building block will provide a powerful tool for a range of diagnostic, prophylactic and therapeutic applications. We will focus on its application to enhance the modular decoration of programmable cell therapies. The success of CAR-T cell therapy against B cell tumours has established the enormous therapeutic power of synthetic cell signalling pathways. However, new approaches are urgently needed for CAR-T cells against T cell tumours, for the approach to become scalable and to avoid causing life-threatening immunodeficiency. We will address fundamental questions for the patient-specific reformatting of CAR-T cells against T cell lymphoma. This work will establish tuned kinetics of CAR-T activation, re-direction of CAR-T cells to different tumour-specific targets, and efficacy of deimmunized Tag/Catcher modules for enhanced specific killing of T cell lymphoma.