Granulocyte is a type of immune cell that has granules with enzymes released during infections, allergic reactions and asthma. A granulocyte is a type of white blood cell. Neutrophils, eosinophils, and basophils are three different forms of granulocytes. Granulocytes are crucial players in innate and adaptive immunity that express a large number of cell surface receptors for the recognition of pathogen invasion and the inflammatory environment. Those include G-protein-coupled chemokine receptors, Fc-receptors, various cytokine receptors, as well as innate immune receptors such as toll-like receptors and C-type lectins.