The Immune System

Innate Immunity

We are all equipped at birth with basic defenses against a number of organisms containing telltale “fingerprints” recognizable to our “first responders”—sentinel macrophages and dendritic cells. Toll-like receptors (named in 1996 for the German word for “amazing!”; Uematsu and Akira, 2007) are specific for fungi and other microbes. When these pathogen-associated molecular patterns (PAMPs) are encountered, mast cells rapidly release histamine and a variety of leukocytes are attracted by chemokines, including NK cells responding to interferon (IFN) (Figure 2.11). Vascular endothelial cells swell and “leak” serum and proteins, causing mmatory exudate (Figure 2.11; Uematsu and Akira, 2007).