Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Microbiology and Immunology

Collaborative Specialization

Molecular Imaging

Supervisor

Dekaban, Gregory A.

2nd Supervisor

Foster, Paula J.

Co-Supervisor

Abstract

A major hurdle hindering the advancement of cell-based cancer vaccines is the inability to non-invasively track in vivo therapeutic cell migration. Within cancer immunotherapy, antigen presenting cell-based (APC) immunotherapies can be dendritic cell-based (DC) and elicit de novo anti-tumor immune responses or formulated as mixed APC-based immunotherapy generated from peripheral blood mononuclear cells (PBMC). Mixed APC-based therapies contain monocytes and B cells as APC and can enhance a pre-existing anti-tumor immune response such that objective anti-tumor responses are observed. In either APC-based formulation, the quantity of anti-tumor APC reaching a secondary lymphoid organ post injection is predictive of the magnitude of the ensuing anti-tumor immune response. This thesis investigates 19F cellular MRI in conjunction with a 19F-perfluorocarbon ( 19F-PFC) labeling agent as a non-invasive, quantifiable imaging modality that serves as a surrogate marker of APC-based cancer immunotherapy effectiveness. Pre-clinical studies involving murine bone marrow-derived DC (BMDC) and human monocytederived DC (moDC) demonstrated 19F-PFC labeling of a high proportion (>95%) of DC without affecting viability, phenotype and function. In vivo migration of 19F-PFClabeled DC to the popliteal lymph node was detected and the subsequent induction of an anti-tumor CD8+ T cell response did not differ compared to control DC. Moreover, this thesis outlines a tumor-bearing mouse model of melanoma suitable for correlating 19 F-PFC-labeled BMDC migration to the lymph node with objective anti-tumor response. Similar to DC, 19F-PFC efficiently labeled human PBMC without altering viability, phenotype, function and in vivo migration. To progress towards a clinical trial to image autologous 19F-PFC-labeled PBMC in humans, a protocol to label human PBMC with 19F-PFC under Good Manufacturing Practice-compliant (GMP) conditions was designed. Nearly 100% of PBMC incorporated 19F-PFC without affecting viability or cell lineage composition and were migration competent as demonstrated by in vivo migration to the popliteal lymph node in a mouse model. Furthermore, mock human ii injections in a ham shank using clinical MR parameters resulted in the first reported detection of 19F-PFC-labeled PBMC at a depth of 1.2 cm, demonstrating that clinical 19F cellular MRI is a suitable non-invasive imaging technique to assess APC-based immunotherapy effectiveness.

Available for download on Friday, July 31, 2020

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