Design of highly immunogenic immunogens for development of monoclonal antibodies to selfpeptides: a combined simulation and experimental study

Monoclonal antibody (mAb) therapy is an immunotherapy that uses highly specific antibodies to bind to particular cells or proteins, in order to stimulate the immune system to destroy those cells. It can therefore be used to target cancers. The process involves binding small components (peptides) derived from tumours to nanoparticles. Immunisation with these peptide-coated nanoparticles results in stimulation of spleen cells to produce a range of antibodies that have the potential to destroy growing tumours. Using hybridoma technology, individually isolated and cloned spleen cells that produce highly specific antibodies to only one target (mAbs) can be isolated and grown on an industrial scale for the development of mAb therapeutics. However, a lot of research is required to not only find the right peptides, but to then ensure they bind to the nanoparticle with the correct orientation so that the immune system subsequently identifies the "self-peptides" as targets.

We will initially use a model self-peptide (gonadotrophin releasing hormone, GnRH), that we have previously studied using simulation and experiment, where we investigated how best to conjugate GnRH to silica nanoparticles (SiNPs). We simulated the adsorption of GnRH(native) and a modified analogue that was cysteine-tagged (cys-GnRH) to silica, and found that the native peptide adsorbed via its arginine residue to leave its N (amino) and C (carboxyl) termini loosely bound and available for further interactions. In contrast, the adsorbed cys-GnRH exposed only its N-terminus to solution. We also simulated cys-GnRH covalently conjugated to BSA (following a carbodiimide chemical reaction to enable crosslinking), finding that this led to better GnRH epitope presentation to solution. A series of immunological studies was also conducted with the peptides adsorbed to SiNPs and with the BSA-peptide-SiNP systems. We found that the GnRH-SiNP induced a drug effect due to its availability of both terminal residues, whereas the cys-GnRH-SiNP did not. We also found that the BSA conjugate systems effectively induced antibody production. This range of immunological and hormonal response is explained by the simulation results and the presentation of the peptides to solution. Hence, this work paves the way for not only a molecular scale insight into therapeutic action, but more significantly, for a rational design of drug delivery and vaccine systems guided by molecular simulation; it is this new strategy that we will exploit in this project.

To demonstrate the utility of the technology, we will use a cancer application in the project. Modelling will be used to select the best candidates with modification to bind onto SiNPs and design conditions for optimum presentation. The designed materials will be deployed experimentally, and the subsequent antibodies and cytokines will be evaluated for tumour cell killing potential. The best candidate(s) will be taken forward into a mAb therapeutic(s).

The project will bring together a multi-disciplinary supervisory team from the University of Strathclyde and TAC. Supervision of the student will come from the Department of Chemical and Process Engineering, the Strathclyde Institute of Pharmacy and Biomedical Sciences, and the ARCHIE-WeSt supercomputer centre. We will also work in close collaboration with Glasgow Caledonian University and University of Glasgow who will supply clinical samples from patients and also provide access to patient information. The industrial supervisor will be Eric Wagner (TAC).

Milestone 1: Peptide Modification and Computational Modelling (Months 1-12; Drs Mulheran, Kubiak-Ossowska labs)
Milestone 2: Immunogen Preparation and Immune Enhancement Evaluation (Months 13-18; Dr Ferro labs, TAC)
Milestone 3: Cancer studies (Months 19-36; Drs Mulheran, Ferro in collaboration with Williams and Souter labs)
Milestone 4: Dissemination and Write-up (Months 43-48); including publications once IP has been protected.