Award details

Understanding how aggregation influences the immune response to recombinant protein therapeutic drugs

Reference	BB/L006391/1
Principal Investigator / Supervisor	Professor Jeremy Paul Derrick
Co-Investigators / Co-Supervisors	Dr Rebecca Dearman, Professor Ian Kimber
Institution	The University of Manchester
Department	School of Biological Sciences
Funding type	Research
Value (£)	461,399
Status	Completed
Type	Research Grant
Start date	30/06/2014
End date	31/07/2017
Duration	37 months

Abstract

The overall aim of the proposal is to study the quality and vigour of the immune response to selected model biotherapeutic proteins, and the aggregates generated from them. Our experimental approach will combine studies using a well characterised (BALB/c strain) mouse model of protein immunogenicity and allergenicity, cultured human and mouse dendritic cells (DCs) and human peripheral blood mononuclear cells (PBMC). The programme will comprise the following tasks: Task 1: Production and characterisation of recombinant mouse and human protein aggregates for use in immunological investigations. Task 2: To determine whether aggregation influences the stimulation of adaptive immune responses in vivo. A mouse (BALB/c) model will be used to monitor whether aggregation of recombinant mouse proteins impacts on: a) IgG isotype distribution b) IgE antibody production c) cytokine production (Interleukin [IL]-2, IL-4, IL-6, IL-10, IL-13, IL-17 and IL-22) d) the balance between antigen-driven CD4+ and CD8+ T lymphocyte responses e) the frequency of regulatory T cells (Tregs) f) the number and phenotype of CD11c+ dendritic cells (DC) in the spleen. Task 3: To determine whether aggregation influences the stimulation of primary immune responses in vitro. To address this question, the elicitation of human T and B cell responses in vitro by aggregated and non-aggregated human/humanised proteins will be characterised. Task 4: Characterisation of the mechanistic basis for differential effects of aggregated and non-aggregated proteins to cause immune stimulation. The investigation will determine whether aggregated and non-aggregated proteins display a differential potential to a) provoke cytokine production by peripheral blood mononuclear leukocytes (PBMC). b) drive the activation of mouse and human DC in vitro.

Summary

Many human diseases, such as multiple sclerosis and cancer, are now treated successfully with drugs which are proteins, rather than small molecules. Protein drugs have the advantage that they are highly specific for a particular target: antibodies are a good example. They can be developed to bind with high affinity to block a specific receptor on the surface of a cell, inhibiting the progress of disease. The use of this new kind of drug in the clinic has grown rapidly over the last two decades, because protein drugs offer the potential for therapeutic intervention which would be difficult or impossible to replicate with small molecule medicines. Although these protein drugs are generally well-tolerated and have opened up exciting new avenues for the treatment of disease, this approach has come with a specific problem. Biotherapeutic proteins (even proteins which are designed to 'look' human) can be recognised as being foreign by the immune system of the patient. This can lead to production of antibodies within the patient which bind to the protein drug and prevent it from functioning effectively. In some cases, the consequences have been more severe, leading to serious adverse health effects in patients undergoing treatment. The origin of this problem lies in the way in which the immune system recognises 'foreign' molecules: a classic question in immunology is, 'why does the immune system not attack its own host's cells?' We now know that there are sophisticated systems for eliminating or inactivating immune cells which would recognise 'self' antigens, to prevent this from happening. This phenomenon is called 'tolerance'. Many protein drugs, although apparently identical to those produced by the host, nevertheless manage somehow to breakdown tolerance and provoke an immune response. It is still unclear exactly how this happens. The aim of this proposal is to investigate this phenomenon and, ultimately, to use the information obtained to inform the design and development of more effective protein drugs in the future. We will focus on one particular aspect which impacts on the immune response to protein drugs- a behaviour known as aggregation. Anyone who has ever boiled an egg is familiar with this behaviour: the white of the egg, after boiling, is solidified. Heat treatment pulls the structure of the protein (albumin) in the egg white apart and the individual protein chains adhere into a dense mesh. This type of behaviour is a general property of proteins, and a version of it can occur in preparations of protein drugs. The presence of aggregates in the preparation is important, as we know that they are very effective at influencing the complex cellular and molecular processes that lead to an immune response. Our proposal will investigate the different immunological responses induced by aggregates from a selection of drug-like proteins. In particular, we seek to determine how these different responses are influenced and modulated by aggregate size, which is the main criterion used to characterise them.

Impact Summary

The proposed research will have beneficiaries from four distinct groupings: 1. Pharmaceutical companies developing biotherapeutic medicines and vaccines. The relevance of the proposed research to the biopharmaceutical sector is obvious and requires little elaboration, given that Lonza are joint applicants and contributing half of the cost of this programme. Specifically, the research will enable the design of more effective therapeutics through the identification and control of features leading to immune responses; this can be applied to both biotherapeutics, where the goal is to minimise immune responses, and vaccines, where stimulation of an effective immune response is important. Results will be disseminated through publications, conference presentations and also the informal contacts which the academic applicants (JPD/IK/RJD) have with industry (subject to agreement with the industrial partner, Lonza). Lonza will also use the results to improve its service offering for the design of therapeutics. Pharmaceutical companies will be able to innovate new biotherapeutics with greater confidence if they can identify and control features (such as aggregation size populations) which are less likely to provoke immune responses. 2. Training of staff employed on the grant The UK hosts a large and expanding bioprocessing community: there are around 15 members of the BBSRC, EPSRC and Industry-funded Bioprocessing Research Industry Club. Promoting the development of training in skills areas relating to bioprocessing products is a priority, and this proposal will contribute to that overall goal. In particular, the combination of protein biochemistry, immunology and animal experimentation will help to develop skills in the employed research staff which will promote their employability and benefit the sector as a whole. Furthermore, as is often the case, funding of a research proposal generates a 'core' of scientific expertise which acts as a nucleus for further industrial collaborations and teaching/training of Masters and PhD students. 3. Regulatory authorities Scientists working for regulatory authorities constitute the third group of more general beneficiaries for this proposal. Examples include the US Federal Drug Administration (FDA), and, in the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) and the National Institute for Biological Standards and Control (NIBSC; until recently part of the Health Protection Agency). Clearly, the problem of unwanted immunogenicity in biotherapeutics has a direct bearing on the regulation of new medicines. A substantial body of scientists work within these and similar regulatory authorities on medicine safety: research which helps to improve guidelines and the monitoring of new drugs will obviously be of value to them. Representatives from regulatory bodies are regular attendees at national and international conferences, and so will be informed of our results through that route, as well as having access through our publications and personal contacts. 4. Patients who will be treated with biotherapeutic medicines Ultimately, the most important grouping to benefit from this proposal will be future patients. The global market for biological medicines in 2011 was $94bn (Thompson Reuters) and is continuing to grow. The numbers of people who will be treated with such drugs in the next 10 years is likely to be in the hundreds of thousands. Reduction or removal of those types of aggregates which would otherwise potentiate the immunogenicity of a drug will have obvious health benefits. An improved understanding of the immunological mechanisms underlying the response to biotherapeutics is therefore going to be an important part of the necessary scientific background which is taken into account when decisions are made about aggregate content in a biological medicine.

Committee	Research Committee A (Animal disease, health and welfare)
Research Topics	Immunology, Pharmaceuticals
Research Priority	X – Research Priority information not available
Research Initiative	LINK: Responsive Mode [2010-2015]
Funding Scheme	X – not Funded via a specific Funding Scheme

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