Therapies and Diagnostics for Immune Dysregulation: Immunomodulation and Tissue Engineering Strategies

Abstract

Dysregulation of the immune system leads to a wide array of pathologies, two of which are food allergies and autoimmune diseases. To clinically improve patient outcomes with these immune system pathologies, diagnostics and therapeutics are major areas of research. While many treatment strategies include avoidance of external triggers—such as food allergen avoidance—or systemic immunosuppression—such as B cell- and T cell-modifying drugs—these approaches do not address the eliciting immune dysfunction. Our approach to circumvent the issues with these therapeutic strategies is to develop a targeted immunotherapy: antigen-specific nanoparticles. For food allergies, our goal is to create an allergen-specific therapy that both targets pathogenic allergen-specific cells and avoids adverse allergic reactions. Thus, we formulated a polymeric allergen-encapsulating nanoparticle therapeutic that effectively conceals allergen within a nanoparticle vehicle that targets antigen presenting cells. These nanoparticle-associated cells subsequently orchestrate a tolerogenic immune response that reduces oral food challenge-induced anaphylaxis by expanding tolerogenic antigen presenting cell populations, reducing allergy effector cell frequencies, and reprograming Th2 cells towards regulatory and anergic phenotypes. While allergen-encapsulating nanoparticle treatment greatly reduces severe allergic reactions, nanoparticles have a heterogenous efficacy with many mice still having mild allergic reactivity. B cell depletion during nanoparticle therapy indicates B cells have a critical role in nanoparticle efficacy. RNA sequencing of the gut after nanoparticle therapy reveals B cell subsets that participate in both regulatory and pathogenic processes. While we show B cells are not necessary for all nanoparticle-induced immune changes such as regulatory T cell induction, we show tolerogenic antigen presenting cell expansion is B cell dependent. Ultimately, the efficacy of allergen-encapsulating nanoparticles as a therapeutic for food allergies could be improved and the mechanisms driving efficacy could be better elucidated. To this end, we took a biomaterial-based diagnostic approach to better glean immune dynamics during nanoparticle therapy. First, we show microporous, subcutaneously-implanted scaffolds recapitulate aspects of the small intestine lamina propria immune landscape during food allergy progression. Second, we use gene expression at the scaffold to identify differences in immune processes between severely allergic, mildly allergic, and nanoparticle-treated mice before allergic symptoms are present. Finally, as a proof of concept for using a biomaterial as a diagnostic for predicting allergic reaction severity, we used scaffold gene expression before and after the occurrence of allergic reactions to classify nanoparticle-treated from allergic mice. As in food allergies, progressive multiple sclerosis has limited treatment options and inadequate diagnostic tests for monitoring immune dynamics at the site of pathology. Thus, we applied this biomaterial diagnostic approach to the monitoring of T cell biology in murine models of progressive multiple sclerosis. We show the scaffold captures autoimmune T cell signaling in the central nervous system. The scaffold also was able to monitor tolerogenic immune changes such as during T cell-targeting anti-VLA4 antibody treatment: gene expression from the scaffold was able to stratify mice based on disease and treatment state. Thus, we next aimed to identify an immune-based target at the scaffold to inform the design of a nanoparticle therapeutic. The scaffold identified CC chemokine signaling upregulated with disease, and we formulated a myelin peptide-encapsulating nanoparticle that reduced this signaling. A single dose showed therapeutic efficacy at reducing symptomatic disease. Collectively, the work in this dissertation demonstrates the potential of using biomaterial diagnostics to identify biomarkers and therapeutic targets for immune-targeted diagnostics and therapies.