Browsing by Subject "tumor cells"
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Item A Review of Dendritic Cell Vaccines in Cancer Treatment and a Managerial Focus on Issues Related to Subject Recruitment(2006-12-01) McFarlin, Tory; Arredondo, LaChelle; Gwirtz, Patricia A.; Oglesby, MichaelMcFarlin, Tory. A Review of Dendritic Cell Vaccines in Cancer Treatment and a Managerial Focus on Issues Related to Subject Recruitment. Master of Science (Clinical Research Management), December 2006, 97 pp., 5 tables, bibliography, 24 titles. Melanoma is form of skin cancer that can become deadly if the cancer progresses to a stage of metastasis. Five year survival rates as low as 10% may be noted in such patients. Decarbazine and Proleukin have been approved by the FDA for the treatment of metastatic melanoma; however both have response rates of approximately 20% or less. New treatment modalities including dendritic cell (DC) vaccines are currently being tested for treating metastatic melanoma with greater safety and efficacy profiles. DC vaccines are made by obtaining a subject’s DCs, priming them with melanoma antigen ex vivo and then injecting them into the patient to initiate an immune response against melanoma tumor cells in vivo. Investigational new treatments such has the DC vaccine must first be tested in clinical trials on research subjects. Subject enrollment issues regarding such a trial can cause delays in advances of the treatment. As an intern with a DC vaccine clinical trial, the author assisted in screening 45 patients and observed many hindrances involving enrollment of subjects. Such hindrances include: low rates of study personnel retention, small patient pools, and competing trials. Recommendations to improve enrollment include: more effective advertisement strategies and increased patient education.Item Approaches to Cloning and Identification of the Ligand for Natural Cytotoxicity Receptor NKp44(2008-07-01) Horton, Nathan C.; Jones, Harlan; Stevens, Stanley; Krishnamoorthy, RaghuHorton, Nathan C., Approaches to Cloning and Identification of the Ligand for the Natural Cytotoxicity Receptor, NKp44. Masters of Science (Microbiology & Immunology), July 2008, 64 pp., 22 illustrations, 37 titles. Natural Killer (NK) cells represent a specialized lymphoid population that mediate innate immune responses against tumor or virally infected cells. NK cell cytotoxicity is regulated by inhibitory and activating receptors. Activating receptors include the Natural Cytotoxicity Receptors (NCRs), 2B4, and NKG2D. The NCRs play a key role in recognition and killing of tumor cells and include the receptors NKp30, NKp46, and NKp44. The ligands for the NCRs are not yet known. NKp44 is of particular interest because it is only expressed on activated NK cells, and is implicated in increased cytotoxicity and HIV infection. To identify and clone the ligand for NKp44, a recombinant fusion protein containing the extracellular domain of NKp44 was constructed and used to identify a cell line, DB, expressing a ligand for NKp44. A directional complimentary DNA (cDNA) library was constructed from this cell line and screened by mammalian expression cloning, resulting in the isolation of several putative cDNA clones of NKp44 ligands.Item Function and Regulation of the Natural Killer Cell Receptor 2B4 (CD244)(2005-05-01) Vaidya, Swapnil V.; Porunelloor A. Mathew; Richard Easom; Hriday DasThe purpose of these studies was to investigate two issues related to the natural killer (NK) cell receptor, 2B4 (CD244) – its in vivo function and transcriptional regulation. In previous in vitro studies, ligation of 2B4 with a monoclonal antibody enhanced the cytotoxicity of NK and CD8 T cells against various tumor cell lines, indicating that 2B4 is an activating receptor. To study the role of 2B4 in vivo, 2B4 deficient (2B4-/-) mice were used. The initial characterization of the 2B4-/- mice indicate a thymic developmental defect with an increase in the immature CD4-/CD8- population in the thyme of female but not male mice. NK cells from the 2B4-/- mice were impaired in activation by IL-2 as compared to wild type NK cells. These results suggest a role of 2B4 in lymphoid development. The in vivo role of 2B4 in tumor rejection was studied in a mouse tumor model in which melanoma cells were injected intravenously and pulmonary metastases enumerated 14 days later. The murine melanoma cell line, B16, was stably transfected with CD48, the counter-receptor for 2B4. Using CD48+ and CD48- B16 cells in tumor experiments indicated that 2B4 functioned as an inhibitory receptor. In addition, a gender-specific role of 2B4 in the rejection of B16 melanoma cells was discovered. 2B4-/- male mice cleared B16 cells more efficiently than wild type male mice, while female 2B4-/- mice were impaired in controlling tumor growth as compared to wild type female mice. In vitro and in vivo studies indicate a complex role for NK cells in the mechanism of this gender effect. Several studies have shown that the expression of 2B4 is upregulated during viral infections and under certain cytokine stimulation. Previously, it has been shown activator protein-1 (AP-1) plays an important role in the transcription of the 2B4 gene. In this study an Ets transcription factor was shown to upregulate the transcription of the gene. This element functions in an AP-1 dependent manner. Stimulation of surface 2B4 down-regulates its own expression by decreasing the activity of the Ets element in the 2B4 promoter. These studies identify a role of 2B4 in lymphoid development and tumor rejection in vivo. The gender-specific defect in 2B4 knock-out mice implicates its role in lupus. The transcriptional studies provide insights into the regulation of 2B4 gene.