What are the functions of each type of granulocyte?

Neutrophils

Neutrophils are the most abundant type of granulocyte in the body. They develop from the myeloid cell lineage within the bone marrow and have a single, multi-lobed nucleus. Neutrophils are part of the innate immune system. They are chemically drawn to bacteria and are among the first white blood cells to respond to invading microbes. In case of an infection, neutrophils migrate through the tissue toward the infection site where they engulf and destroy target cells by phagocytosis. 

Eosinophils

Eosinophils are granular leukocytes that develop from the myeloid cell line within the bone marrow and are mainly found in connective tissues of the stomach and intestines. They have one double-lobed, U-shaped nucleus. Although eosinophils are present in almost all immune responses, they are most active during allergic reactions and parasitic infections. The granules in the cytoplasm of eosinophils contain molecules such as peroxidase, cationic protein, and major basic protein (MBP), which are toxic to parasites. 

Basophils

Granular leukocytes of myeloid lineage, basophils have a single bi-lobed, S-shaped nucleus. They are primarily responsible for the body’s allergic response. Basophils contain histamine granules in their cytoplasm. In case of an allergic reaction, basophils release histamine granules, which dilate blood vessels, increasing blood flow and permeability of capillaries, enabling leukocytes to be transported to the sites of infection. Basophils also release heparin, a blood thinner that inhibits blog clotting.