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CD8+ T-lymphocytes (CTLs) are central to the immunologic control of infections and are currently at the forefront of strategies that enhance immune based treatment of a variety of tumors. Effective T-cell based vaccines and immunotherapies fundamentally rely on the interaction of CTLs with peptide-human leukocyte antigen class I (HLA-I) complexes on the infected/malignant cell surface. However, how CTLs are able to respond to antigenic peptides with high specificity is largely unknown. Also unknown, are the different mechanisms underlying tumor immune evasion from CTL-mediated cytotoxicity. In this dissertation, I investigate the immunogenicity and dysfunction of CTLs for the development of novel T-cell therapies. Project 1 explores the biochemical hallmarks associated with HLA-I binding peptides that result in a CTL-immune response. The results reveal amino acid hydrophobicity of T-cell receptor (TCR) contact residues within immunogenic CTL-epitopes as a critical parameter for CTL-self
onself discrimination. Project 2 develops a bioinformatic and experimental methodology for the identification of CTL-epitopes from low frequency T-cells against tumor antigens and chronic viruses. This methodology is employed in Project 3 to identify novel immunogenic CTL-epitopes from human papillomavirus (HPV)-associated head and neck cancer patients. In Project 3, I further study the mechanisms of HPV-specific T-cell dysfunction, and I demonstrate that combination inhibition of Indoleamine 2, 3-dioxygenase (IDO-1) and programmed cell death protein (PD-1) can be a potential immunotherapy against HPV+ head and neck cancers. Lastly, in Project 4, I develop a single-cell assay for high-throughput identification of antigens targeted by CTLs from whole pathogenome libraries. Thus, this dissertation contributes to fundamental T-cell immunobiology by identifying rules of T-cell immunogenicity and dysfunction, as well as to translational immunology by identifying novel CTL-epitopes, and therapeutic targets for T-cell immunotherapy.
onself discrimination. Project 2 develops a bioinformatic and experimental methodology for the identification of CTL-epitopes from low frequency T-cells against tumor antigens and chronic viruses. This methodology is employed in Project 3 to identify novel immunogenic CTL-epitopes from human papillomavirus (HPV)-associated head and neck cancer patients. In Project 3, I further study the mechanisms of HPV-specific T-cell dysfunction, and I demonstrate that combination inhibition of Indoleamine 2, 3-dioxygenase (IDO-1) and programmed cell death protein (PD-1) can be a potential immunotherapy against HPV+ head and neck cancers. Lastly, in Project 4, I develop a single-cell assay for high-throughput identification of antigens targeted by CTLs from whole pathogenome libraries. Thus, this dissertation contributes to fundamental T-cell immunobiology by identifying rules of T-cell immunogenicity and dysfunction, as well as to translational immunology by identifying novel CTL-epitopes, and therapeutic targets for T-cell immunotherapy.
ContributorsKrishna, Sri (Author) / Anderson, Karen S (Thesis advisor) / LaBaer, Joshua (Committee member) / Jacobs, Bertram L (Committee member) / Lake, Douglas F (Committee member) / Arizona State University (Publisher)
Created2017
Description
An estimated 267 million women worldwide are HSV-2 seropositive, including roughly 20% of reproductive-aged American women. HSV-2 is a neurotropic virus that establishes a persistent, life-long infection that increases risk for STI acquisition in individuals. The vaginal epithelium represents a critical first line of defense against infection, and during acute infection, underlying immune mechanisms in the epithelium may be critical to protect against disease pathogenesis. The recently identified pro-inflammatory cytokine IL-36gamma has been shown to be expressed at mucosal epithelia, including the female reproductive tract (FRT) and may be an important factor in host defense. Although IL-36gamma has been shown to be induced in the FRT after exposure to microbial products, the contributions of IL-36gamma to host defense mechanisms in response to this clinically relevant STI pathogen are not well understood. This dissertation describes the regulation of IL-36gamma in the FRT and explores its contribution to the host response against genital HSV-2 infection.
To test the hypothesis that IL-36gamma is a key regulator of mucosal inflammation and immunity in the FRT, hormonal regulation of IL-36gamma in the FRT was investigated using estrogen- and progesterone-conditioned mice. From this preliminary study, it was shown that progesterone dampens IL36G expression relative to estrogen and may potentially increase susceptibility to infection. Next, the impact of IL-36gamma treatment on HSV-2 infection and replication in human 3-D vaginal epithelial cells was explored. In parallel, the impact of intravaginal IL-36gamma delivery on HSV-2 disease pathogenesis was evaluated using a lethal murine challenge model. IL-36gamma pre-treatment significantly limited HSV-2 replication in vitro and in vivo and was associated with transient neutrophil infiltration that corresponded with decreased disease severity and increased survival in mice. Last, the requirement for IL-36gamma in host defense was investigated utilizing IL-36gamma-/- mice in a lethal HSV-2 murine challenge model. Following infection, IL-36gamma-/- mice exhibited significantly impaired neutrophil recruitment, decreased overall survival time, and significantly increased viral neuroinvasion relative to wild type mice. Collectively, these data indicate that IL-36gamma is a crucial regulator of HSV-2-induced neutrophil infiltration and appears to function in a previously uncharacterized manner to limit viral neuroinvasion in genital HSV-2 disease pathogenesis.
To test the hypothesis that IL-36gamma is a key regulator of mucosal inflammation and immunity in the FRT, hormonal regulation of IL-36gamma in the FRT was investigated using estrogen- and progesterone-conditioned mice. From this preliminary study, it was shown that progesterone dampens IL36G expression relative to estrogen and may potentially increase susceptibility to infection. Next, the impact of IL-36gamma treatment on HSV-2 infection and replication in human 3-D vaginal epithelial cells was explored. In parallel, the impact of intravaginal IL-36gamma delivery on HSV-2 disease pathogenesis was evaluated using a lethal murine challenge model. IL-36gamma pre-treatment significantly limited HSV-2 replication in vitro and in vivo and was associated with transient neutrophil infiltration that corresponded with decreased disease severity and increased survival in mice. Last, the requirement for IL-36gamma in host defense was investigated utilizing IL-36gamma-/- mice in a lethal HSV-2 murine challenge model. Following infection, IL-36gamma-/- mice exhibited significantly impaired neutrophil recruitment, decreased overall survival time, and significantly increased viral neuroinvasion relative to wild type mice. Collectively, these data indicate that IL-36gamma is a crucial regulator of HSV-2-induced neutrophil infiltration and appears to function in a previously uncharacterized manner to limit viral neuroinvasion in genital HSV-2 disease pathogenesis.
ContributorsGardner, Jameson Kyle (Author) / Herbst-Kralovetz, Melissa M (Thesis advisor) / Lake, Douglas F (Committee member) / Jacobs, Bertram L (Committee member) / Boehmer, Paul E (Committee member) / Hogue, Ian B (Committee member) / Arizona State University (Publisher)
Created2019