Browsing by Subject "T cells"
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Item Cd4 T Cell Activation And Ox40 Agonist Immunotherapy In Tuberculosis(2023-09) Gress, AbigailAfter Mycobacterium tuberculosis (Mtb) infection millions of effector T cells traffic to the lungs, but relatively few find antigen and become activated. We used an antigen receptor reporter mouse (Nur77-GFP) infected with Mtb to distinguish recently activated CD4 T cells from others in the lungs. Recently activated Nur77-GFPHI cells more often expressed protective markers and were enriched for expanded TCR clonotypes. Nur77-GFPHI cells differentially expressed co-stimulatory genes including Tnfrsf4/OX40 and were functionally more protective than Nur77-GFPLO. Nur77-GFPLO cells more often expressed markers of terminal exhaustion, cytotoxicity, and the trafficking receptor S1pr5, associated with vascular localization. A short course of immunotherapy with an agonist monoclonal antibody targeting OX40+ cells during early infection transiently expanded CD4 T cell numbers and shifted their phenotype towards parenchymal protective cells, which decreased the lung bacterial burden and extended host survival, offering an additive benefit to antibiotics. We have newly identified OX40 as a conserved marker of recently activated CD4 T cells at the infection site and a target for immunotherapy in tuberculosis.Item Characterizing the migration and therapeutic potential of CD8 tumor-infiltrating lymphocytes(2023-06) Gavil, NoahBeginning in the 19th century, immunologists slowly uncovered the mechanisms ofcancer immunosurveillance, ultimately identifying thymic-dependent “T” lymphocytes (T cells), and not antibodies, as the primary mediators of cancer cell elimination and control. T cell surveillance is performed by diverse subsets. After antigen encounter, T cells differentiate, adopting many phenotypic fates. In settings of acute infection, T cells diversify into ‘effector’ and long-lived ‘memory’ states. While some memory T cells circulate throughout the body, others remain resident, patrolling tissues locally. The migration and function of memory T cells has been well studied, providing a systemic view of immune surveillance for microbial pathogens. In settings of chronic antigen, such as cancer, antigen-specific T cells diverge from the memory program, existing along a spectrum of differentiation and exhibiting restrained functional capabilities. While the early stages of cancer immunosurveillance mirror immune responses to microbial pathogens, the T cell surveillance of progressive malignant tumors is poorly understood. Many studies describe the heterogeneity of tumor-infiltrating T cells (TILs). Generally, the density of CD8+ TILs correlates with improved prognosis, but the density of CD8+ TILs with resident-memory (TRM) phenotypes better predicts patient outcomes and responsiveness to immunotherapies. These TRM-like cells may directly control tumor growth, but their migration properties have not been directly studied, leaving their direct function unknown. Importantly, newer data shows that many CD8+ TILs are bystanders, specific for microbial pathogens, not tumors. Reactivation of these bystander T cells with cognate peptide can orchestrate potent anti-tumor immune responses. In this thesis, I study the migration properties of tumor-specific and virus-specific CD8+ T cell subsets. Distinct resident populations of CD8+ TILs exist, differing based on the presence or absence of chronic antigen. Resident CD8+ TILs do not recapitulate the resident T cell programs of healthy tissues. I also investigated the anti-tumor immune mechanisms initiated by antiviral CD8+ TILs reactivation. Cytokine production and innate immune mechanisms were the predominant source of tumor killing. Taken together, T cell immunosurveillance is characterized by the coexistence of T cell subsets that represent lineages associated with chronic antigen exposure and memory T cells, which possess potent therapeutic potential (e.g. TRM).Item Differentially Expressed Gene Transcripts Using RNA Sequencing from the Blood of Immunosuppressed Kidney Allograft Recipients(2016-02-29) Dorr, Casey; Wu, Baolin; Guan, Weihua; Muthusamy, Amutha; Sanghavi, Kinjal; Schladt, David; Maltzman, Jonathan; Scherer, Steven; Brott, Marcia; Matas, Arthur; Jacobson, Pamala; Oetting, William; Israni, Ajay; isran001@umn.edu; Israni, AjayThis is the FPKM and clinical covariate data from a paper in PLOS One. These data will be useful for future researchers to study gene expression patterns over time before and after immunosuppression and kidney transplantation. We removed subject names and any other identifiers in order to de-identify the subjects.Item The inhibitory receptor PD-1 differentially regulates effector and anergic autoreactive CD4 T cells during Type 1 Diabetes(2013-07) Pauken, Kristen ElaineA variety of mechanisms act to prevent the inappropriate targeting of host tissues by the immune system, but these mechanisms can fail, leading to development of autoimmunity. Type 1 Diabetes is an autoimmune disease caused by T cell-mediated destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans. This work focused on understanding islet-reactive CD4 T cells during Type 1 Diabetes progression by comparing T cell responses in diabetes-susceptible non-obese diabetic (NOD) mice to diabetes-resistant (B6.g7) mice. Our knowledge of how these cells are normally regulated and how that regulation breaks down leading to diabetes is limited due to a lack of reagents to track these cells in mice with normal T cell repertoires. The goal of this work was to develop models to study physiological numbers of islet-reactive CD4 T cells in mice in order to gain a better understanding of how these cells are regulated with an emphasis on one critical inhibitory pathway involving Programmed-Death 1 (PD-1). Using these models, we showed that in diabetes-susceptible NOD mice, the majority of islet-reactive CD4 T cells become activated, but the pathogenic subset capable of contributing to disease was relatively small. Rather, the majority of the population was adequately controlled by the host through induction of T cell anergy. In diabetes-resistant mice, islet-reactive CD4 T cells were present, but failed to become activated and subsequently did not infiltrate the pancreas. The inhibitory receptor PD-1 was important for suppressing CD4 T cell effector functions in NOD mice, including proliferation, trafficking to the pancreas, and localization within the pancreas. However, blockade of PD-1 did not promote CD4 T cell trafficking to the pancreas in diabetes-resistant mice. Unexpectedly, in NOD mice, PD-1 was predominantly involved in suppressing the functions of an activated effector population, not maintaining the anergic population. These findings provide new insight into the regulation of islet-reactive CD4 T cells, and show that PD-1 differentially contributes to the suppression of these cells.Item Overcoming Obstacles to Glioma Immunotherapy(2014-04) Litterman, AdamGlioma is a type of malignant tumor of the non-neuronal cells of the central nervous system, the glia. These tumors are the most common malignant tumors of the central nervous system. The most aggressive and most prevalent of these, glioblastoma multiforme (GBM) is a deadly disease with a grim prognosis, with median survival at diagnosis of less than a year and a half. Standard treatment with irradiation and the DNA alkylating drug temozolomide yields incremental improvement in survival over irradiation alone but better therapies remain needed. Immune therapies are an emerging class of therapies that have shown great promise in the treatment of hematopoietic malignancies and solid tumors. These therapies harness the capability of the immune system to target and kill large numbers of tumor cells specifically, and it is has been suggested that most or all durable responses to treatment of solid tumors involve generation of an anti-tumor immune response. Several anecdotal reports of dramatic responses in GBM patients after receiving cancer vaccines (a type of immune therapy) suggest that immune therapies for glioma could yield substantial increases in survival of patients with these tumors. However, the overall record of vaccines for the treatment of this disease has been marked by failure, and substantial barriers remain to the implementation of other types of immune therapies in glioma patients. Several mechanisms by which tumors in general, and brain tumors in particular, evade the activity of the immune system have been outlined. These include accumulation of immune suppressive cell types, tumor intrinsic changes that directly suppress the activity of infiltrating immune cells, and brain specific mechanisms of immune privilege. While these mechanisms are doubtless operative in many cases, accumulating evidence from clinical trials of adoptive transfer of T cells demonstrate that the accumulation of sufficient numbers of tumor-specific T lymphocytes at the tumor site can result in an overwhelming anti-tumor immune response and associated durable clinical responses. Therefore, my research over the past several years has focused on clinically relevant mechanisms in glioma patients that present obstacles to the development of a robust T cell mediated anti-tumor immune response. In this thesis, I outline experiments performed to understand and develop strategies for overcoming two obstacles to expanding large numbers of tumor specific cytolytic T lymphocytes in glioma patients: the anti-proliferative effect of the alkylating drug temozolomide on in vivo T cell expansion by cancer vaccination, and the differentiated phenotype of ex vivo expanded T cells for adoptive immunotherapy that is associated with diminished proliferative potential in vivo. A focus in these experiments is the targeting of tumors with T cells that are specific for antigenic determinants derived from tumor-specific mutations. Engineered T cell responses targeting individual patient-specific mutations may someday lead to significant improvements in the efficacy of immune therapy for glioma, and ultimately to improved outcomes for patients with these malignancies.Item Reprogramming T cell lymphocytes to induced pluripotent stem cells(2012-12) Bared, KaliaThe discovery of induced pluripotent stem cells (iPSC) provided a novel technology for the study of development and pharmacology and complement embryonic stem cells (ES) for cell therapy applications. Though iPSC are derived from adult tissue they are comparable to ES cells in their behavior; multi-lineage differentiation and self-renewal. This makes iPSC research appealing because they can be studied in great detail and expanded in culture broadly. Fibroblasts were the first cell type reprogrammed to an iPSC using a retrovirus vector, since then alternative cell types including lymphocytes have been used to generate iPSC. Different types of vectors have also been developed to enhance iPSC formation and quality. However, specific T lymphocyte subsets have not been shown to reprogram to a pluripotent state to date. Here, we proposed to derive iPSC from peripheral blood effector and central memory T cells, reasoning that the resultant iPSC will maintain the epigenetic memory of a T lymphocyte, including the T cell receptor (TCR) gene rearrangement. This epigenetic memory will enable the differentiation and expansion of T cell iPSC into professional T cells containing a specific TCR. These could then be used for cell therapy to target specific antigens, as well as to improve culture techniques to expand T cells in vitro. We studied different gene delivery methods to derive iPSC from different types of T lymphocytes. We assessed the viability of viral transduction using flow cytometry to detect green fluorescent marker contained in the viral construct and quantitative real time polymerase chain reaction (qRT-PCR) to detect Oct4, Klf4, Sox2, and c-Myc gene expression. Our results demonstrate that the Sendai virus construct is the most feasible platform to reprogram T lymphocytes. We anticipate that this platform will provide an efficient and safe approach to derive iPSC from different T cell subsets, including memory T cells.Item Revolutionizing T cell Therapy for Pancreatic Cancer: Harnessing the Power of T cell Receptor Exchange Mice(2023-03) Rollins, MeaganPancreatic ductal adenocarcinoma (PDA) is a lethal cancer characterized by a suppressive tumor microenvironment (TME) including elevated levels of TGF. The adoptive transfer of T cell receptor (TCR) engineered T cells specific to mesothelin (Msln) can effectively target PDA, but efficacy is limited by the suppressive TME that promotes engineered T cell dysfunction. T cell receptor (TCR) transgenic mice represent an invaluable tool to study antigen-specific immune responses. In the pre-existing models, a monoclonal TCR is driven by a non-physiologic promoter and randomly integrated into the genome. Here, we create a highly efficient methodology to develop T cell receptor exchange (TRex) mice, in which TCRs, specific to the self/tumor antigen mesothelin (Msln), are integrated into the Trac locus, with concomitant Msln disruption to circumvent T cell tolerance. We show that high-affinity TRex thymocytes undergo all sequential stages of maturation, express the exogenous TCR at DN4, require MHC class I for positive selection and undergo negative selection only when both Msln alleles are present. By comparison of TCRs with the same specificity but varying affinity, we show that Trac targeting improves functional sensitivity of a lower affinity TCR and confers resistance to T cell functional loss. By generating P14 TRex mice with the same specificity as the widely used LCMV-P14 TCR transgenic mouse, we demonstrate increased avidity of Trac-targeted TCRs over transgenic TCRs, while preserving physiologic T cell development. To test the hypothesis that TGFβ is a major driver of engineered T cell dysfunction in PDA, we knocked out Tgfbr2 using CRISPR/Cas9 in in vitro activated Msln-specific TRex cells. The loss of Tgfbr2 signaling in high affinity (1045) Msln-specific TRex T cells drive increases in markers of effector T cells such as Klrg1, Cxcr3, and CD44. When transferred into orthotopic PDA tumor-bearing mice, both Tgbr2-WT and Tgbr2-/- engineered T cells traffic to tumors driven by increased frequency and number of cDC1 and cDC2 dendritic cells. With vaccination, the engineered T cells cause a 10-fold reduction in tumor weight at day 13 post tumor and are highly proliferative. Tumor-infiltrating Tgbr2-/- cells upregulated IFNg, TNFa, and Granzyme b and decreased markers of terminal exhaustion PD-1 and Lag3. Our studies suggest, interfering with TGFβ signaling can alter T cell fate prior to transfer and maintain effector differentiation within the TME promoting cytotoxic Klrg1+ T cells at the expense of PD-1+ exhausted T cells and leading to tumor control.