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Title: Exploiting the use of induced pluripotent stem cell derived immune cells for immunotherapy
Author: Sachamitr, Supatra
ISNI:       0000 0004 6062 4157
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2015
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Immunotherapy traditionally made use of biological agents such as cytokines and monoclonal antibodies. Such first generation therapies lack antigen specificity and fail to induce immunological memory, suggesting that cell therapies may provide the next generation of treatments that are more discerning in their mode of action. Nevertheless, difficulties in obtaining sufficient immunologically-relevant cell types from patients has limited their success. Given that induced pluripotent stem cells (iPSC) may be generated from patients, we have investigated the feasibility of deriving two cell types whose availability is restricted in vivo: regulatory T cells (Tregs) and CD141+ cross-presenting dendritic cells (DCs). We describe the optimization of protocols for differentiation and purification of CD141+ DCs, focussing on their utility as a therapeutic vaccine for HIV-1. We investigate their phenotype, chemotactic capacity, phagocytic ability and propensity to harbour infectious virus. We also assess their immunostimulatory capacity and ability to cross-present exogenous antigen to MHC class I-restricted T cells. Our findings led us to speculate that iPSC-derived DCs (iPDCs) possess fetal phenotype, which is characterised by excessive secretion of IL-10 and failure to secrete IL-12, under all but the most stringent conditions. We hypothesised that constitutive secretion of IL-10 may be responsible for maintaining the fetal phenotype, a hypothesis we tested by developing an appropriate mouse model. iPSCs were derived from WT and IL-10-/- mice and were shown to differentiate into iPDCs which recapitulate the fetal phenotype observed among human cells. However, loss of the endogenous Il-10 gene failed to restore full immunogenicity and IL-12 secretion. Finally, we developed protocols for differentiation of FoxP3+ Tregs from iPSCs, a feat that has not previously been achieved. These findings pave the way for the differentiation of Tregs from iPSCs reprogrammed from antigen-specific pathogenic T cells, thereby creating a source of Tregs with matched specificity for therapeutic intervention.
Supervisor: Fairchild, Paul Sponsor: Clarendon Fund
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Stem cells ; Dendritic cells ; HIV infections--Immunological aspects ; Immunotherapy ; HIV ; induced pluripotent stem cells