M.Sc. / Dense non-aqueous phase liquids (DNAPLs) are groups of chemicals often found beneath the water surface when chemical contamination of water occurs and they are called groundwater contaminants. Their improper storage and extensive use in industries as well as their slow degradation provide a long term source for of low level contamination of ground- and river water. Evidence from both human and animal studies suggests that volatile organic and organochlorinated compounds (specific types of DNAPLs), may increase host susceptibility to microbial infection, induce alterations in the maturation of effector immune cells and compromise immune surveillance mechanisms. These effects of DNAPLs hold special relevance for people living with HIV/AIDS. In light of this, the present study investigated the in vitro immunological effects of the two most common DNAPLs contaminants, Trichloroethylene (TCE) and Aroclor-1254 (ARO) in peripheral blood mononuclear cells (PBMCs) of immunocompromised and healthy donors. TCE and ARO were successfully dissolved in cell culture medium and added to freshly isolated PBMCs in a 1:1 ratio. Following incubation, cell functionality and cytotoxicity (or immunotoxicity) were assessed using MTT and LDH. Viability was confirmed and/or cell death analyzed by flow cytometry. Culture supernatants were used to assess NO and cytokine production as well as for quantification of viral replication. TCE and ARO induced a significant (p<0.05) decrease in cell viability/functionality in a dose-dependent manner. Flow cytometric analysis of cell death pathways indicated that TCE and ARO induced apoptosis. These chemicals also induced the secretion of both NO and proinflammatory cytokines suggesting that they may induce apoptosis via an inflammatory pathway, which may explain the mitochondrial dysfunction as determined by the MTT assay. ARO effects were more prominent than those of TCE, and both were more detrimental to HIV positive PBMCs compared to uninfected cells. The viral p24 levels increased in a dose-dependent fashion suggesting an effect for TCE and ARO on viral replication. This research concludes that DNAPL-contamination is detrimental to especially immuno-compromised systems.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:8245 |
| Date | 31 March 2009 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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