IFR regulatory factors are ancient molecules conserved throughout the evolution of metazoans; they play a fundamental roles in innate and adaptative immune system. To date 11 IRF family have been described in vertebrates and invertebrates.
Previous studies showed that in vertebrates, IRF4 was expressed in most types of immune cells, and had critical functions in B cell differenciation and immunoglobulin production.
Other studies on chicken found that IRF4 was mainly expressed in the bursa, bursal lymphocytes and thymus . Con A induced the expression of IRF4 in spleen cells.
As for IRF8 in mouse, it specifically bound to the expression of type I IFR and IFR-inducible MHC Class I genes. IRF2 had the same rôle and played a regulatory one in cells of the immune system. The aim of this work is the research of such factors in an invertebrate : the sea star Asterias rubens.