The antimicrobial protein that triggers inflammation is Histamine. Histamine is involved in the inflammatory response and has a central role as a mediator of itching. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues.
Once released from its granules, histamine produces many varied effects within the body, including the contraction of smooth muscles tissues of the lungs, uterus, and stomach; the dilation of blood vessels, which increases permeability and lowers blood pressure among other effects.