Tumor-distal immune suppression promotes tumor growth by preventing the recruitment of leukocytes to the tumor-proximal microenvironment. Tumor necrosis factor (TNF)-a is both secreted by and expressed on the cell-surface (mTNF-a) of macrophages. When stimulated with LPS, tumor-burdened host (TBH) macrophages secrete more TNF-a than normal host (NH) macrophages. In this study, I showed that mTNF-a is elevated both in freshly isolated and stimulated TBH macrophages. Additionally, I analyzed the expression of Fas and FasL on freshly isolated and LPS-stimulated macrophages and found no differences between TBH and NH macrophages. Fas and Fas ligand (FasL) cell-surface expression was analyzed on NH and TBH T-cells. While no difference was observed in freshly isolated cells, cell-surface expression of both proteins remained higher in TBH T-cells than NH T-cells after mitogenic stimulation. Fas and FasL analysis was also extended to the MethKDE fibrosarcoma and I found that these tumor cells express high levels of FasL. Because past observations show increased TNF-a mRNA expression in TBH macrophages relative to NH macrophages, I hypothesized that NF-kB activation may be increased as well. NF-kB is a transcription factor whose activation is required for TNF-a transcription. I observed increased NF-kB activation in both splenic and peritoneal TBH macrophages. Interestingly, electrophoretic mobility shift analysis (EMSA) suggests that different species of NF-kB were found in each distinct population of macrophages. Together, these data demonstrate that cell-surface tumoricidal molecules and NF-kB are dysregulated in the tumor-burdened host. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/9609 |
| Date | 30 October 2003 |
| Creators | McConnell, Michael James |
| Contributors | Biology, Elgert, Klaus D., Rutherford, Charles L., Winkel, Brenda S. J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | MichaelMcConnellFINAL.pdf |
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