A new study has identified for the first time that specialised immune cells (phagocytic cells) exist in certain varieties of sea corals and anemones. These cells help understand how the organisms protect themselves from viruses and bacteria in the marine ecosystem. 

What is phagocytosis?  

• Immune cells ingest and destroy foreign and damaged cells through a process called phagocytosis.  

• The phagocyte may be a free-living one-celled organism, such as an amoeba, or one of the body cells, such as a white blood cell. 
• In some forms of animal life, such as amoebas and sponges, phagocytosis is a means of feeding. 
• In higher animals, phagocytosis is chiefly a defensive reaction against infection and invasion of the body by foreign substances (antigens). 

Source: Down To Earth