Granulocyte white blood cell. Coloured transmission electron micrograph (TEM) of an eosinophil granulocyte, a type of white blood cell. Eosinophils, like all white blood cells, are part of the body's immune system. They are involved in the body's allergic response and help to defend the body from invading parasites. Granules (oval-shaped) contain enzymes used to destroy invading organisms. Like all granulocytes, eosinophils have a multi-lobed nucleus (yellow and purple). Magnification: x3400 when printed at 10 centimetres across.