The Experimental Therapeutics Laboratory aims to improve chronic and acute health outcomes by exploring novel immunotherapeutic approaches to treat and prevent cancer, allergy and other diseases including chronic and acute infections and uncontrolled inflammation in sepsis.
1. Revolutionising Vaccine Development and Deployment
An ongoing collaboration between Melbourne-based Biotech Company Sementis Ltd. and the Experimental Therapeutics Laboratory, has resulted in the development of a novel vaccine vector platform, the Sementis Copenhagen Vaccine (SCV) system. This platform is a vaccinia virus-based live viral vector, and through genetic reformation, the virus has been re-created to be a safer and more efficient vaccine delivery system. In addition, we have engineered a manufacturing-friendly packaging cell line to complement this vector system for large scale commercial manufacturing. We are currently investigating the SCV vaccine for use in a range of immunotherapeutic applications, including allergies, cancer and infectious diseases (see A1-4 below).
Vaccine-based PhD and Honours projects: All research students involved in these projects will be provided with opportunities for advanced technical and analytical training in molecular biology, virology and immunology, and invaluable translational and commercial experience by working in close collaboration with our clinical and industry partners. Training will have a strong emphasis on commercial application, and as such, students will gain access to knowledge and experience that is not generally available in a pure academic context. Ultimately, this will improve their employment prospects by endowing them with expertise relevant to, and much sought-after in the biotechnology and biopharmaceutical sector in Australia and abroad.
Our current research projects
-
Multicomponent vaccines to prevent infectious diseases
We have successfully developed and tested single and combined SCV-based vaccines targeting chikungunya and Zika virus, and shown that they provide single shot and long-lived immunity in mouse models of disease. This includes prevention of arthritis after chikungunya challenge, and complete protection from Zika-mediated fetal abnormalities and damage to the male testis (Nat Commun. 2018; 9(1):1230 and Mol Ther. 2017; 25(10):2332). We have now progressed to non-human primate challenge studies, GLP-manufacture and quality control testing of this vaccine, pre-requisites for anticipated clinical trials in 2019. This is a major achievement and provides strong and independent validation of our innovative approach to rapid vaccine development, as well as a clear commercial manufacturing pathway.
This experience underpins the development of all subsequent SCV-based vaccines in this field, including the following specific vaccines which are all currently under development:
- Combined HepA/HepB vaccine, which will be benchmarked against Twinrix®, the current commercially available combination vaccine, thereby demonstrating superior (or at least equivalent) protection, but far more economical to manufacture.
- Revolutionary influenza vaccine that will provide robust cell-mediated cross-protection by targeting conserved matrix and nuclear proteins, and with seasonal humoral immune responses provided by co-expression of rationally-considered hemagglutinin sequences.
- Vaccines against; i) a range of emerging infectious diseases for which there is either no commercial vaccine available (MERS, SARS and Lassa fever), or; ii) remerging diseases with vaccine production issues due to rate-limiting manufacturing processes dependent on eggs (YF17D yellow fever vaccine), or chicken embryonic fibroblasts (the recently approved Bavarian Nordic IMVAMUNE® smallpox vaccine), which despite being much safer than the traditional vaccinia-based vaccines, cannot satisfy current biodefence stockpiling contracts.
- An economical multi-serotype Ebola vaccine encapsulated in a proprietary coldchain-independent dissolving microneedle delivery system, which will provide protection against the Zaire ebolavirus (most virulent Ebolavirus species to humans), Sudan (related to the Reston species), Reston (not virulent in humans), Tia Forest (formerly Ivory Coast or Cote d’Ivoire ebolavirus ICEBOV or CIEBOV), and the Bundibugyo strain (related to Tia Forest strain).
-
Re-educating the peanut allergic immune system using active vaccination
Allergic diseases are increasing in prevalence worldwide, with an estimated 70% increase by 2050. Food allergy, a potentially life-threatening condition, has emerged as a major public health concern in developed countries. In Australia, peanut allergy incidence has increased in the age group 0-5, with life-long persistence in 80% of the affected children. Currently, there are no licensed therapeutics and to date, most of the allergen-specific immunotherapy trials have been associated with varying degrees of desensitisation, long-treatment regimens leading to poor compliance, high rates of adverse events, and failure to achieve long-lasting, clinical tolerance to peanuts.
We are working towards an effective vaccine for use in peanut allergy that has the immunomodulatory potential to reprogram the immune response to peanut allergens from an allergic to a tolerant phenotype. We have used our SCV vaccine platform to develop peanut hypoallergenic vaccines (SCV-PHAV), which in mouse models of allergy can prevent allergen sensitisation by the induction of tolerant T cell and antibody responses. In parallel, co-cultures of human dendritic cells (DCs) and CD4 T cells from clinically confirmed peanut allergic individuals have demonstrated the capacity of vaccine-instructed DCs to facilitate a tolerant T cell response. Now we aim to progress the SCV-based peanut hypoallergenic vaccines from pre-clinical therapeutic validation, through to GLP grade manufacture of the vaccine and toxicology studies in preparation for Phase-I human clinical trials. We have three specific aims to advance experimental and commercial development in a timely fashion:
Aims:
1. Functional characterisation, safety assessment and in vivo therapeutic potential of four different SCV-based vaccine candidates in mouse models of allergy.
2. Immunogenicity studies in human allergic individuals, using ex vivo vaccination simulation assays employing the lead and alternate vaccine candidates identified in Aim 1.
3. Manufacture, quality control and toxicology studies to facilitate Phase-I clinical trials. -
Oral passive immunotherapeutics to prevent and treat oesophageal cancer
Oesophageal cancer (OC) kills more than fifty percent of patients in the first three years after diagnosis. In Australia, ~1400 new cases of OC are diagnosed each year, and 500,000 worldwide. Existing treatments for OC (surgery, chemotherapy and radiation) do not show high remission rates and cause severe side effects and physical sequelae that significantly decrease the quality of life for sufferers. Furthermore, there are no effective therapeutic agents to prevent OC or treat one of its main precursor conditions, Barrett oesophagus (BO). Together with ConCa Pty Ltd and Sementis Ltd, we aim to advance Lumenab®, a patent protected polyclonal antibody (pAb) formulation to locally target the human ephrinB receptor 4 (EPHB4) in the lumen of the oesophagus, to kill both OC and BO diseased cells. Lumenab® differentiates itself from current treatments, in that it brings therapy to pre-cancer stages in patients with Barrett’s oesophagus, thereby increasing the probability of positive outcomes. Together with Beston Global Food Company Ltd, we aim to produce Lumenab® in a cost-effective and commercially-scalable manufacturing process from bovine colostrum and chicken egg yolk, using the EPHB4 vaccine (SCV-EPHB4). We are establishing the prophylactic and therapeutic efficacy of the different Lumenab® preparations in in vitro and ex vivo models of BO and OC disease, and are assessing the potential off-target toxicity of Lumenab® treatment in a large preclinical animal model. Our hypothesis is that anti-EPHB4 pAbs from bovine colostrum and egg yolk will significantly decrease the viability of diseased cells in culture and tissue explants from BO and OC patients, without side effects on healthy cells and tissues. We are working towards achieving the following specific aims:
1. Generate pAb Lumenab® batches with maximum antibody potency from bovine colostrum and egg yolk from Sementis Ltd SCV-EPHB4-immunised dairy cows and layer chickens.
2. Determine the efficacy and dosage of Lumenab® prototype batches in vitro on Barrett’s oesophagus and oesophageal cancer cell lines, as well as on patients’ biopsy explant and organoid cultures, leading to final selection of IgG or IgY pAb for commercial progression.
3. Carry out off-target toxicity studies with the chosen form of Lumenab® in a large pre-clinical animal model (pigs), in preparation for subsequent Phase-I human clinical trials. -
Vaccination during pregnancy
Two vaccines are currently recommended for pregnant women: the influenza vaccine and a diphtheria-tetanus-acellular pertussis vaccine. It is likely that vaccination against respiratory syncytial virus and group B streptococcus will also become recommended, potentially resulting in 4 or more vaccinations administered during pregnancy. Many vaccines do not produce strong immune responses and require multiple doses for optimal protection. For pregnant women, ideally a vaccine should produce a strong immune response quickly and with one dose. This is particularly apparent for protection against emerging infectious diseases such as Zika virus.
This project will investigate whether an additive approach to vaccination results in best outcomes for the pregnancy and offspring, or whether our new SCV vaccine delivery platform can be utilised to combine antigens to generate equal or better immune responses with one vaccination. This would result in minimal intervention during pregnancy.
Non-specific effects of vaccination will also be investigated, as vaccination may potentially guard against pregnancy loss after pathogen challenge. Preclinical mouse studies will be performed to generate safety data for novel vaccine platforms, and investigate immune outputs in side-by-side comparisons of traditional vaccine protocols against next generation vaccines during pregnancy.
2. Controlling the inflammatory response
Inflammation is essential for the protection and regeneration of damaged cells and tissue; however lack of control or unwanted inflammation is often the root cause of many disease states. High mobility box group 1 (HMGB1) is an highly conserved ‘danger’ molecule involved in the perpetuation of inflammation in a diverse array of acute and chronic inflammatory conditions including but not limited to sepsis, trauma, neurological disorders, cancer, and autoimmune disease. Importantly, inhibiting HMGB1 in a range of preclinical models of disease have increased survival and disease control, strongly indicating that innovative therapeutics targeting HMGB1 have the potential to be ‘game changers’ in the treatment of many different ailments. Furthermore, knowledge of circulating HMGB1 levels will complement current diagnostic and prognostic markers of disease, increasing certainty for doctors and patients.
PhD and Honours projects: All research students involved in these projects will be provided with opportunities for advanced technical and analytical training in molecular biology and immunology, with strong emphasis on investigative experimental design and discovery of new knowledge.
Our current research projects
-
Therapeutic targeting of alarmin HMGB1 for the control of sepsis
Sepsis remains a significant health burden, with a major clinical need for therapeutics to control the dysregulated immune response that results in high levels of mortality and morbidity. Adult survivors are often left immunosuppressed, and surviving neonates are at increased risk of compromised neurodevelopmental outcomes.
The nuclear protein HMGB1 is highly conserved and a late immune mediator in sepsis with a wide therapeutic window. We have generated anti-HMGB1 antibodies and shown that therapeutic administration to adult and neonatal mice with sepsis improves survival. Furthermore, treated mice do not exhibit secondary morbidities such as immunosuppression of developmental abnormalities.
This project will determine the mechanism by which our antibody therapy improves outcomes. Using established models of disease, and genetically-modified mice, cells and tissues at specific times will be analysed by quantitative RT-PCR, flow cytometry and ex vivo assays to assess the interactions between HMGB1 and cell fate in sepsis and how administered antibodies inhibit this response. Together with assessment of HMGB1 in clinical samples, these findings will be used to support progression of our therapeutic antibodies into clinical trials.
-
Determining the role of HMGB1 in myositis
The ‘idiopathic inflammatory myopathies’ (IIMs) are systemic autoimmune disorders characterised by muscle inflammation leading to muscle weakness together with a myriad of extramuscular manifestations. The term encompasses polymyositis (PM), juvenile dermatomyositis (JDM), adult dermatomyositis (DM), sporadic inclusion body myositis (IBM) and necrotising autoimmune myopathy (NAM), also known as immune-mediated necrotising myopathy (IMNM). They have distinct pathological features, but the aetiopathogenesis of each subtype remains largely unknown. Recently, there has been increased interest in the complex role the innate immune system plays in initiating and perpetuating these conditions, and how this may differ between subtypes.
High mobility group box protein 1 has been implicated in a diverse number of immune-mediated conditions including rheumatoid arthritis, SLE and IIMs. Aberrant extra-nuclear expression of HMGB1 has been demonstrated in the invading inflammatory cells, myofibers and endothelial cells in patients with IIM and this down-regulates following immunotherapy. The diseased muscle fibers expressing HMGB1 are not necrotic and hence the aberrant HMGB1 expression likely arises from active nuclear transport in these conditions, rather than passive release from damaged cells. Aberrant HMGB1 expression in IIMs occurs even in muscle tissue of patients with short disease duration where inflammatory infiltrate is lacking. This highlights an early and critical role for HMGB1 in the disease initiation process.
In collaboration with Dr Vidya Limaye, we are continuing to investigate the role that HMGB1 plays in IIM, and whether assessment of HMGB1 isoforms can be used as a prognostic biomarker of disease.
3. Smart materials sciences
Bringing together people from different science disciplines to work toward a common goal can lead to creative and innovative outputs. Here we combine our biological training and commercial expertise with traditional surface chemists to push toward translatable solutions to common problems.
PhD and Honours projects: All research students involved in these projects will be provided with opportunities for advanced technical and analytical training within the applied chemistry field, with strong emphasis on translatable experimental design and discovery of new knowledge.
Our current research projects
-
Advanced materials for water solutions
As a vital resource it is important that everyone is afforded access to clean and safe water. Research currently underway is looking at solutions to maximize water use efficiency and availability to secure this resource into the future. Advanced materials aimed at detecting and removing water based toxins and pathogens are currently being developed in collaboration with Dr Sally Plush (UniSA), Dr Justin Chalker (Flinders University) and our Industry partner Puratap Pty Ltd. One of the current aims of this research is the remediation of water contaminated with perfluorinated compounds. It is envisaged that this research will deliver cost effective solutions for water purification and quality determination.
-
Manipulating the inflammatory response to biomaterial implants
New clinical applications for biomaterial implants are rapidly emerging, and novel approaches to their manufacture and the material from which they will be constructed from are warranted. This is because they need to be able to interact favourably with the body’s defence systems and this project aims to achieve this goal using nanotechnology. In a cross-disciplinary collaboration with Prof Krasimir Vasilev (UniSA), we aim to provide a mechanistic understanding of how surface nanotopography affects inflammatory responses. We have experimental evidence demonstrating that engineered surface nanotopography in combination with surface chemistry downregulates the expression of proinflammatory cytokines from primary macrophages. These exciting findings are important because they show that it may be possible to engineer the nanotopography of a biomedical device surface in a manner which leads to a desired and predictable level of inflammation and subsequent foreign body reaction (FBR) medical implants and tissue engineering constructs.
