The role of prostaglandins in the regulation of fish immunity

•Fish leukocytes produce PGs in vitro in response to PAMPs, calcium ionophores and AA or EPA.•Fish leukocytes produce PGs in vivo upon immunostimulation.•PGs regulate the main biological activities of fish leukocytes.

Prostaglandins (PGs) play a key role in the development of the immune response. These molecules are produced by a variety of cells including leukocytes, macrophages being the most important source of PGs for the innate immune system. PGs can elicit a variety of effects depending on the inflammatory milieu but also on the presence of specific PG receptors in many cell types. The biosynthetic pathways of prostaglandins, their production by cells of the immune system and their functions as immune-modulators, have been poorly studied in fish. This review is based on the available published data and our own experience and highlights recent advances in our understanding of the role for PGs in the regulation of fish immunity. The evolutionary conservation of their functions in fish is proof of their importance as a regulator of the immune response.