Lategan, Kim Leigh2026-06-172026-06-172017https://hdl.handle.net/10566/24515Heavy metals and nanoparticles may be released into the environment due to their use and applications. Sources of high, toxic metal concentrations may result from leachates from hazardous waste sites, discharge from industrial plants, and effluents from wastewater treatment plants being released into the environment. Nanoparticles may be found in a number of consumer products, and are used in medical applications such as drug delivery, bioimaging and biosensing. The release of heavy metals and nanoparticles to the environment may directly or indirectly impact abiotic and biotic systems. Three heavy metals and three nanoparticles were selected for this study. The heavy metals selected include cadmium (Cd), silver (Ag) and copper (Cu). The nanoparticles (NPs) chosen were silver nanoparicles (AgNPs), graphene oxide nanoparticles (GONPs) and carbon dots (CDs). These compounds were selected to evaluate the potential effects these compound may have on the immune system. The murine macrophage cell line RAW 264.7 and human whole blood cell cultures (WBCs) were selected as immune system representatives to assess the effects of heavy metals and nanoparticles on the immune system. The effects of heavy metals and NPs on RAW cells were monitored either in the absence or presence of the mitogen, lipopolysaccharide (LPS). The effects of heavy metals and NPs on WBCs were evaluated under basal conditions or in the presence of LPS or phytohaemmagglutinin (PHA). A number of parameters were monitored. These parameters included cytotoxicity, inflammatory biomarkers, cytokines of the acquired immune system and a proteome profile analysis. The first objective of this study was to assess the effects Cd, Ag and Cu on immune system biomarkers. No effects on were seen on cultures not stimulated by LPS. Cd was more cytotoxic than Ag, with Cu having no effect on cell viability of the RAW cells. The same trend was seen when evaluating the inflammatory biomarkers, nitric oxide (NO) and interleukin 6 (IL-6). Evaluating the effects of the metals on WBCs and the cytokines representing the innate (IL-6), humoral (IL-10) and cell mediated immunity (IFNγ) found that all the cytokines were reduced by the metals. The results show IL-6 was inhibited by Cu at lower concentrations than Cd, while Ag upregulated its synthesis. IL-10 was inhibited by Cd at lower concentrations than Cu, and Ag inhibited the production of this cytokine the least. IFNγ was reduced by higher concentrations of Ag, followed by Cu, and then Cd. The second objective of this study was to evaluate the effects AgNPs had on the immune system biomarkers. AgNP concentrations had no negative effect on RAW cell viability at concentrations used. However, AgNP cytotoxicity of WBCs was evident. Under basal conditions, AgNPs induced inflammation in RAW cells and WBCs respectively. Under a simulated inflammatory response, AgNPs inhibited the inflammatory response for both RAW and WBCs. The acquired immune cytokines IL-10 and IFNγ were both induced by AgNPs in the absence of PHA. IL-10 was partially inhibited by AgNPs when evaluated in the presence of PHA. Proteome profiles of RAW cell supernatants show that AgNPs do in fact modulate specific protein synthesis. Upregulated proteins due to AgNP exposure indicate induction of specific proteins indicative of inflammatory responses and wound healing. WBC supernatant proteome analysis indicates modulation of anti-inflammatory properties by AgNPs. The third objective was to monitor the effects of GONPs on the immune system biomarkers. GONPs were cytotoxic to both RAW and WBCs. In the absence of mitogens, GONPs elicited an inflammatory response from RAW and WBCs respectively. This activation was further corroborated by proteome profile analysis of both experimental cultures. GONPs inhibited LPS induced IL-6 synthesis and PHA induced IFNγ synthesis by WBCs in a dose dependent manner. In the absence of mitogens, GONPs stimulated IL-10 synthesis by WBCs. GONPs modulate immune system biomarkers and these may pose a health risk to individuals exposed to this type of nanoparticle. The last objective of this study was to evaluate the effects of CDs on the immune system. CDs were cytotoxic to RAW and WBCs respectively. Biomarkers associated with inflammation was induced by CDs under basal conditions for both RAW and WBCs respectively. The humoral immune system regulating cytokine IL-10 was increased by CDs under both basal and PHA activated WBCs. Proteome analysis supported the inflammatory data as proteins identified are associated with inflammation and provide potential biomarkers to be assessed upon CD exposure. The heavy metals and NPs assessed in this study can potentially be detrimental to human health as they are cytotoxic and induce immunomodulatory cytokines. This could potentially result in immunosuppression or immunostimulation in individuals exposed to these compounds.enHeavy metalsNanoparticlesIn vitro effectImmune systemThesis