Macrophages, commonly known as white blood cells (WBC), are the main units of the immune system. They surround, ingest, and destroy invading organisms. This process is called phagocytosis, which is depicted in the image below. This means "cell eating". Phagocytosis is a part of the inflammatory reaction of innate immunity. Macrophages also attach to invading antigens and take them to be destroyed by other components of the adaptive immune system.