Granulocytes are leukocytes which contain granules in their cytoplasms. These granules have important proteins in them. Also called polymorphonuclear leukocytes, granulocytes have a nucleus, which is lobed into two or three segments. Granulocytes include neutrophils, eosinophils, and basophils. They are produced in the bone marrow by the regulatory complement proteins. They fight bacterial and fungal infection. The most abundant granulocyte is the neutrophil, which has neutrally-staining cytoplasmic granules.