The eel immune system: present knowledge and the need for research.

The European eel, Anguilla anguilla, is one of the most important warm water fish species cultured in southern Europe and the Mediterranean as well as in northern countries including Germany, the Netherlands and Denmark. The Japanese eel, A. japonica, is an important cultured fish in several Asiatic countries including Japan, China and Taiwan. During recent decades, research has been performed to elucidate the immune response of these species against different pathogens (viruses, bacteria or parasites). Nevertheless, there is very limited information in terms of both cellular and humoral immune responses. This review summarizes the present knowledge relating to the eel immune system and includes new data.