Molly Stevens - Bionanoscience 'Engineered Organoid Co-Cultures to Advance Vaccine Delivery'
Despite significant advances in vaccine development, only a handful of vaccines have been approved for respiratory delivery. Although the mucosal barrier poses significant delivery challenges, it is hypothesised that intranasal or aerosolised vaccines could lead to better local protection and superior long-term protection compared with other delivery methods. While novel formulations can be tested in animal models and in vitro models, we still struggle to understand mechanistically the factors which make a respiratory mucosal vaccine successful. Work within the Stevens group has focussed on novel formulations for synthetic vaccines (LNP or polyplexes), as well as controlled drug delivery platforms such as pulsatile microparticles, capable of releasing therapeutics (i.e. small molecule, protein, nanoparticles) at pre-determined time points and polymer formulations which allow for long term, sustained drug release over 180 days. The Provine group has shown that lymphoid organoids derived from human tonsils can be used as an in vitro system to study vaccine responses, demonstrating the ability to model vaccine responses to adenoviral vector vaccines. In complementary systems, the Pollock group has demonstrated that human lymph node samples are technologically advanced models for the assessment of adaptive immune responses post vaccination. Meanwhile, the Lambe group has developed mucosal organoid systems which act as ideal models to assess the efficiency of vaccines delivered to respiratory sites like the nose and lung. These organoid systems are designed to mimic the complex physiological interactions between the lung, the primary site of infection for respiratory pathogens, and the lymphatic system, where the immune responses is initiated, however, in their current usage do so in isolation. In this project, we aim to develop and understand the interactions between lymphoid organoids and mucosal organoids as a semi-reductionist model of infection and immune response for vaccine development. We aim to use these models to assess how pulsatile or long-term exposure to a vaccine formulation influences the humoral response in lymphoid organoids, and how these two delivery mechanisms change uptake and or response in mucosal organoids.
We will synthesise pulsatile particles using two-photon 3D printing techniques within the Stevens group. The particles designed for long-term, sustained release will be synthesised using previously established microfluidic methodologies. Both drug delivery systems will then be loaded with the vaccine of interest (e.g. adenoviral vectors, LNPs, polyplexes). To enable the co-cultures, we will first utilise SLA 3D printing techniques in the Stevens group to design and print customised, permeable membrane inserts which fit into Transwell® inserts. These inserts will allow for separation of the lymphoid and mucosal organoids whilst facilitating interactions via diffusion of exogenous factors between the two organoids. In collaboration with the Provine, Pollock and Lambe groups, we will culture lymphoid organoids derived from human tonsils or lymph node cells and mucosal organoids in the custom co-culture setup. We will utilise multiplexed tissue molds in tandem with cryo-sectioning to perform high-throughput imaging (immunostaining and Raman imaging) of the organoid systems to characterise the tissue. Additionally, we will study cytokine production between the organoid systems. Once the co-culture systems are established, we will study how infection of the mucosal organoids with a model vaccine (e.g. adenoviral vectors, LNPs, polyplexes), leads to a humoral response in the lymphoid organoids or lymph node slices and vice versa. To monitor uptake and distribution, we will incorporate Raman vibrational tags synthesised within the Stevens group into the model vaccines, and use stimulated Raman spectroscopy (SRS) imaging, an orthogonal imaging technique to immunofluorescence imaging. We will use scRNAseq and other relevant methodologies on the co-culture systems to investigate the cells mediating immune interactions between the mucosal and lymphoid organoids, including cytokine interactions. Taken together, we believe that by studying the interactions between these tissues in semi-reductionist models we can gain better mechanistic insights into designing more efficient mucosal vaccines.
Brief description of training opportunities
The key benefits of this cross-disciplinary project are the broad range of techniques the prospective DPhil student will be exposed to. The DPhil student will work at the interface of bioengineering, advanced organoid culture and vaccine immunology, learning a broad range of techniques such as CAD design, 3D printing (two-photon, SLA), Raman imaging (spontaneous and stimulated), immunostaining, flow cytometry, scRNAseq, and primary organoid culture.
Primary supervisor
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Molly Stevens
John Black Professor of Bionanoscience
