We have pioneered a novel technology using heterobifunctional antibodies (SureTACs: surface removal targeting chimeras) for the degradation of membrane proteins. SureTACs induce proximity of a transmembrane E3 ligase and a cell surface target protein, resulting in the ubiquitination and internalisation and lysosomal degradation of the target. Advantages of SureTAC technology compared to conventional antagonising antibodies include reduced off-target toxicity, improved tissue specificity, and the possibility to target currently undruggable proteins.

Insulin receptor isoform A, uniquely expressed in tumours unlike the ubiquitously-expressed isoform B, is a compelling breast cancer target. Selective isoform engagement is challenged by homology and structural constraints resulting from epitope/membrane proximity. We leveraged our synthetic miniprotein platform—with efficient evolution of high-affinity, selective binding, robust developability, and a variety of topologies and paratope architectures to engage distinct epitopes—to engineer subnanomolar, isoform-selective binders.

We have developed nanobodies targeting a class of glutamate receptors, the mGlu receptors, a family of GPCRs that control synaptic transmission. We show that nanobodies acting as allosteric modulators of the mGlu2 receptor can limit glutamate release at the synapse. A nanobody rescues the behavioral deficits in preclinical models of schizophrenia. It penetrates the brain after systemic injection and has a long-lasting effect in the brain after one dose.

Generation of therapeutic antibodies to transmembrane protein targets in a properly folded and presented form can be very challenging. cDNA, soluble antigens (extracellular domains), as well as evolving platforms like Virus-Like Particles and nanodiscs all have advantages and disadvantages for antigen presentation. In this talk, I will explore various methods for the generation of complex transmembrane proteins with a focus on the application of different antigen platforms for antibody discovery.

Maintaining membrane protein targets in their native state is a crucial part of any drug discovery campaign. The relatively recent development of extraction systems that protect and preserve the membrane environment around membrane proteins has gone a long way to supporting the native state. In this talk I will show an extensive study of the SMA-based extraction system showing a novel high-throughput method that accelerates SMA selection. I hope the talk will leave you with:

• An appreciation of the opportunities offered by SMA solubilisation
• Insights into the method itself
• An understanding of the influence of polymer type on extraction

Membrane proteins remain a major challenge for antibody-based drugs. We have developed an antibody discovery and optimisation platform that pairs immune diversities with a highly-engineered yeast to robustly target membrane proteins. We demonstrate the power of this platform through the identification and subsequent optimisation of an agonistic anti-CCR5 IgG. Additionally, we report on the isolation of novel T cell engaging anti-CD3 HCAbs and their subsequent validation in a bispecific format. 

Venom derived cysteine-rich miniproteins (knottins) have potential as therapeutic agents to block ion channels but suffer from manufacturing difficulties, short half-lives and a lack of specificity.  Maxion have developed a novel molecular format wherein a peripheral CDR loop of an antibody has been replaced by a knottin. This format, termed a KnotBody, combines the benefits of both scaffolds with the antibody gaining the functionality of a scaffold pre-disposed to the blockade of ion channels and the knottin enjoying the extended half-life and the additional specificity conferred by the antibody molecule. This presentation illustrates the generation and optimisation of KnotBody inhibitors. 

Blocking the ATP-gated P2X7 ion channel ameliorates inflammatory diseases and cancer in animal models. We generated nanobodies that modify P2X7 gating. Cryo-EM analysis revealed the mechanism of action of these robust single immunoglobulin domains. A single injection of nanobody-encoding AAV vectors blocks P2X7 for weeks, ameliorating colon cancer. We further used these nanobodies as targeting ligands by insertion into the AAV capsid to target P2X7-expressing endothelial cells in kidney inflammation.

• Antigen: antigen design and format strategies for maximizing expression, immunogencity, and focusing antibody responses 
• Antibody: pros and cons of different approaches 
• Discovery: pros and cons of different approaches to efficiently identify diverse antibody panels
• Characterization: Strategies to efficiently select lead candidates​

Integral membrane proteins with complex multi-spanning topologies provide significant opportunities for development of therapeutic antibodies. Examples of these proteins include GPCRs, ion channels, transporters, adhesion molecules, and tumour-associated antigens. Whilst discovery of antibodies to these targets is regarded as challenging, strategies are emerging enabling antigen generation to drive discovery efforts. This presentation provides case studies highlighting discovery of antibodies to GPCRs, ion channels, and a tumour-associated antigen.

To enable the identification of novel antibodies targeting cell membrane proteins, we used a combination of whole-cell panning, next-generation sequencing, and bioinformatics. Antibody sequences encoding specificity for membrane proteins were identified using mathematical modeling-based prediction of antibody enrichment during panning. Using this approach, we identified a diverse pool of membrane protein-targeting antibodies for phenotypic, function-first discovery.