The proPO and clotting system in crustaceans

Abstract

Aquaculture production has made impressive progress during the past two decades especially with regards to crustaceans, such as shrimp, prawn and lobster. Research in terms of immunity has received a high priority to control disease and to ensure long-term survival of shrimp culture. Invertebrates, including crustaceans, do not have acquired immunity, instead they have an innate immune system, which includes Ž . melanization by activation of the prophenoloxidase activating system proPO system , a clotting process, phagocytosis, encapsulation of foreign material, antimicrobial action Ž . and cell agglutination Soderhall, 1999 . Research in the area of innate immunity in arthropods is rapidly progressing, whereas shrimp immunity research has been a subject of minor interest compared to similar research performed on other crustaceans and insects. The penaeid shrimp can be a good model to use mainly because they are short lived compared to many other crustaceans. In this paper, we review what is known so far about crustacean defence mechanisms, particularly of penaeid shrimp, with special emphasis on the proPO and the clotting system.