How do the functions of macrophages and neutrophils differ?
1. Neutrophils are primarily circulating phagocytes recruited from the blood to sites of inflammation during acute events where they phagocytose opsonised organisms and dead cells. Macrophages are derived from blood monocytes and are found resting in the tissues. These would include Kuppfer cells in the liver and alveolare macrophages in the lung. Macrophages also are excellent at phagocytosis but upon activation (usually occuring via interferon gamma priming from NK T cells combined with a secondary stimulus such as bacterial Lipopolysaccharide acting through CD14 or Toll like receptor 4) they secrete pro-inflammatory cytokines such as IL-1, IL-6, IL-12 and IL-18 and TNF alpha and other molecules such as procoagulant tissue factor. Under certain circumstances they can also secrete anti-inflammatory cytokines such as IL-10. It is this role as a cytokine factory that makes macrophages centrally important in the regulation of both the innate and adaptive immune system. The wide variety o
