The expression of a neuronal nuclear antigen (Ri) recognized by the human anti-Ri autoantibody in the developing rat nervous system.

Anti-Ri is a human autoantibody that recognizes a neuronal nuclear antigen (Ri) of unknown function. To ascertain the possible role of the Ri antigen in neuronal development, we analysed the pattern of the anti-Ri immunoreactivity in the developing rat nervous system. Neurons of the retina, except the photoreceptors, and central but not peripheral nervous system were anti-Ri-positive. The intensity of the immunoreactivity followed the sequence of neuronal maturation. Germinal cells of the periventricular layer and migrating neuroblasts in the intermediate zone were Ri-negative. These data suggest Ri antigen may play a role in the postmigratory maturation of neurons of the CNS.