Peptides produced (usually in liver) and released in response to inflammatory molecules from the immune system. They bind to cell wall of the microbe and increase membrane permeability to kill pathogen. Acute phase proteins are produced by epithelial cells and phagocytes, and provide protection at epithelial surfaces. There are two major families of antimicrobial peptides: defensins and cathelicidins. These include C-reactive proteins, alpha-1 acid glycoproteins, haptoglobulin, fibrinogen, serum amyloid A and complement.