Human kappa-like expression in the axial organ of the sea star Asterias rubens (Echinoderma)

The axial organ of sea star Asterias rubens is a primitive immune organ which in certain conditions produces an antibody-like factor (ALF). This A.L.F. presents homologies with the human kappa chain. The ALF could be composed of many kappa chains devoid of any disulfide bond. The ontogeny of kappa expression was studied. Just after metamorphosis of the sea star, certain mesodermic cells which become axial organ cells express human kappa-like activity.