Type 1 diabetes is an autoimmune disorder caused by the destruction of insulin secreting ß cells in the pancreas. The aim of this project is to explore the potential of using solid-coated microneedles to target skin dendritic cells with an auto-antigen to induce tolerance for the treatment of type 1 diabetes. A novel coating formulation has been developed to accommodate peptides with different lipophilicities. The optimised coating formulation and electro-polishing of the microneedle surface were key factors which enhance the efficiency of peptide delivery. Optimised coating formulation did not show adverse effects on peptide bioactivity or trigger a pro-inflammatory response. The delivery route (microneedle vs. intradermal injection) was shown to be the main factor that influenced the clearance of peptide from murine skin in vivo. Other factors such as temperature, skin hydration state and peptide solubility were also shown to have effects on peptide clearance. Two autoantigens were used to induce tolerance in non-obese diabetic mice – a potent mimotope m31 and endogenous antigen WE14. The proliferation profile of transferred carboxyfluorescein succinimidyl ester labelled BDC2.5 T cells in pancreatic lymph nodes in non-obese diabetic mice was used as a readout for the development of immunological tolerance. The results herein provide the first demonstration that WE14-coated microneedles were able to induce tolerance in vivo, showing reduced proliferation of BDC2.5 T cells. Additionally, this project examined the potential of short-term topical application of betamethasone to enhance peptide-induced tolerance. Both human and mouse dendritic cells showed a pro-tolerogenic state after treatment with topical application of betamethasone in vitro. However, full dose betamethasone was shown to have systemic toxicity in vivo, resulting in depletion of CD11c+ dendritic cells and CD4+ T cells. Diluted topical betamethasone facilitated a small effect on BDC2.5 proliferation; however no advantage on enhancing antigen specific immunotherapy was observed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:665880 |
| Date | January 2015 |
| Creators | Zhao, Xin |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/76452/ |
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