Browsing by Subject "NK cells"

Now showing 1 - 3 of 3
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    Engineering human pluripotent stem cells for enhanced lymphocyte development and function
    (2012-10) Knorr, David Arthur
    Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) provide accessible, genetically tractable and homogenous starting cell populations to efficiently study human blood cell development. These cell populations provide platforms to develop new cell-based therapies to treat both malignant and non-malignant hematological diseases. Our group has previously demonstrated the ability of hESC-derived hematopoietic precursors to produce functional natural killer (NK) cells. hESCs and iPSCs, which can be reliably engineered in vitro, provide an important model system to study human lymphocyte development and produce enhanced cell-based therapies with potential to serve as a "universal" source of anti-tumor lymphocytes for novel clinical therapies. My studies have focused on the generation of NK cells from hESCs and iPSCs, their function both in vitro and in vivo against a variety of different tumor types, and modification of these cells with genetic constructs to enhance their anti-tumor capabilities.
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    Harnessing Natural Killer Cells for Improved Therapeutic Potential
    (2021-08) Kim, Hansol
    Cellular immunotherapy provides durable control for infected and transformed cells. However, current Natural Killer (NK) cell therapy products are limited by effector persistence. To this end, three strategies to improve the efficacy of NK cell-based therapies are discussed. Killer immunoglobulin-like receptors (KIR) are developed during maturation of NK cells. It showed that KIR develops primarily between CD56brightCD94high and CD56dimCD94high stages. Major demethylation activities were observed during the development of KIR at its proximal promoter region. Ascorbic acid showed to facilitate the development of KIR in collaboration with Ten-eleven translocation (TET) enzymes. NK cells with adaptive immunological properties persist and expand in response to cytomegalovirus (CMV) infection. The levels of intracellular metabolites were analyzed and showed that adaptive NK cells have relatively higher levels of metabolites associated with glycolysis, purine, and pyrimidine metabolism. This supports the notion that adaptive NK cells have upregulated metabolic profiles, and have capacity to expand upon reactivation of CMV which is similar to the characteristics of memory T cells. To address challenges associated with inconsistencies of the manufactured product, and treatment cost, we developed a triple gene-edited induced pluripotent stem cell (iPSC) platform for broad patient-based adoptive cell therapy. First edit is to introduce non-cleavable CD16 which prevents reduced efficacy by antibody-dependent cellular cytotoxicity (ADCC). Second edit allows iPSC-derived NK cells, termed iNK, to persist without supplementation of exogenous IL-15 by introducing IL-15 receptor fusion. The last edit was to avoid daratumumab-induced fratricide by knocking out CD38 on the surface of the iNK cells. These engineered iNK cells persisted in vivo without supplementation of exogenous cytokine and could be combined with daratumumab for enhanced treatment of multiple myeloma. The gene-edited iNK cells exhibited metabolic features and gene expression profiles similar to those of adaptive NK cells which has broad off-the-shelf potential for the treatment of advanced cancer.
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    Investigating the mechanisms underlying antibody-mediated effector functions in malaria and Multisystem Inflammatory Syndrome in Children (MIS-C)
    (2024-06) Dick , Jenna
    Antibodies have multiple functions within the body to provide host protection, including interacting with Fc receptors on innate immune cells to destroy pathogens or cells infected by pathogens. We studied antibody-mediated cellular responses in the context of two infections: malaria, a parasitic infection, and SARS-CoV-2, a viral infection. Plasmodium falciparum (P.f) is the main cause of malaria worldwide and is major cause of morbidity and mortality. Deaths occur because of the blood stage of the P.f. life cycle. To date, there is no effective blood stage malaria vaccine. Natural killer (NK) cells inhibit the growth in the blood through interacting with antibodies via antibody dependent cellular cytotoxicity (ADCC). A subset of NK cells in malaria, known as adaptive NK cells, lack the FcR chain and have enhanced ADCC. However, it is unclear if the lack of FcRchain is the reason for increased functionality or if it only serves as a marker. Using CRIPSR/Cas9, we found that ablating the FcR chain did not enhance ADCC. Using cohort of subjects from a malaria clinical study in Mali, we then searched for other alterations in malaria NK cells that could explain the enhanced functionality. We found that the expression of Sigelc-7, an inhibitory receptor, is decreased on NK cells from individuals with malaria and that decreased expression of Siglec-7 correlates with increased ADCC. These data provide evidence that the host may increase the number of Siglec-7 negative NK cells to aide in the clearance of infected RBCs through ADCC. I then investigated antibody-mediated effector functions in Multisystem Inflammatory Syndrome in Children (MIS-C), a rare and severe complication of SARS-CoV-2 infection that is characterized by multi-organ involvement and substantial inflammation. Little is known about antibody-mediated cellular responses in MIS-C. We show that monocytes in MIS-C were hyperfunctional while NK cells were hypofunctional for antibody-dependent cellular destruction and cytokine production. We also show multiple ways leading to decreased cytotoxicity for NK cells, including phenotypic exhaustion of NK cells and cytokine-induced associations. Together, our results reveal unique dysregulation in antibody-mediated responses in MIS-C that contribute to the immune pathology of this disease and may be amenable to immunomodulation. Overall, this thesis provides insight into the mechanisms underlying antibody-mediated cellular functions in malaria and MIS-C that can be utilized in developing therapeutics and vaccine targets for these diseases .