Macrophage Cells Secrete Specific Cytokines and Accumulate Activated Interferon Regulatory Factor 3 after Multi-Walled Carbon Nanotube Exposure

Macrophage Cells Secrete Specific Cytokines and Accumulate Activated Interferon Regulatory Factor 3 after Multi-Walled Carbon Nanotube Exposure

The health consequences of human exposure to carbon-based nanomaterials are not fully understood and the effects that such materials have on the immune system have not been adequately characterized. To determine if the innate immune system is modulated by exposure to carbon-based nanomaterials, the extracellular accumulation of an array of cytokines was measured in cell culture media obtained from mouse macrophage cells (RAW264.7) following exposure to carbon nanotubes (CNTs) or fullerene (C60). Accumulation of a specific subset of cytokines was observed after exposure to multi-walled CNTs (MWCNT), but was not observed when cells were exposed to single-walled CNTs (SWCNTs) or C60. Additionally, the accumulation of the activated (phosphorylated) form of the interferon regulatory factor 3 (IRF3) transcription factor and associated interferon beta (IFNβ) was observed after MWCNT exposure. These data suggest that IRF3 is a mediator of MWCNTactivated signal transduction pathways in macrophage cells. Furthermore, our data show that MWCNTs induce an innate immune response at subtoxic doses and suggests that MWCNT exposure may result in chronic inflammation and compromised immunity.