Alveolar macrophages (AMs) are the primary immune cell type responsible for phagocytizing inhaled particles and initiating the inflammatory response. Crystalline silica and multi-walled carbon nanotubes (MWCNT) are two particles shown to have deleterious effects on lung macrophages. Silica is an environmental and occupational hazard, inhalation being associated with systemic inflammation, lung fibrosis, and autoimmune disease. MWCNT are an emerging concern and present unique challenges in toxicity evaluation due to numerous variables contributing to bioactivity.
