3D animation showing a mast cell releasing histamine. The allergen (green particles) triggers the mast cell to release histamine as an immune response. Mast cells are a type of white blood cell, and play a important role in the immune system. Histamine (represented here by purple bubbles) is an organic compound produced by mast cells as an inflammatory response to foreign antigens. Histamine acts as a vasodilator to increase blood flow and capillary permeability, which allows white blood cells to infiltrate an injured or infected area. © ThevisualMD/Science Source
