Immunocyto chemical Reactions in The Brittle-Star: Ophiocomina Nigra After Immunization

All echinoderms (Echinodermata),except holothurids, possess an axial organ (AO) as part of their coelomic and haemal system. Immunocytochemical positive reactions were observed in 1973 in the sea star Asterina gibbosa (Asterid, Echinoderm) [1]. After injections of various proteins. It seemed interesting to look for similar actions in the Ophuirid: Ophiocomina nigra (another echinoderm) which possesses also an axial organm. The sea star axial organ, an ancestral lymphoïd organ shows immune adaptative reactions [2] and presents a primitive antibody [3]. The question was are the Ophiocomina and Asterina gibbosa axial organs similars from the point of view of immuno competence?. So, we have repeated an experimental protocol in Ophiocomina nigra which resembles to the sea star one of 1973, at the level, exclusively, of cytologic observations.