DISTRIBUTION OF MYELIN LIPID ANTIGENS IN ADULT AND DEVELOPING RAT SPINAL-CORD

We examined the distribution of myelin antigens recognized by monoclon al antibodies (mAbs) 01 and 04 in the developing ventral white matter of the cervical spinal cord of the rat using immunogold-labeled ultrat hin cryosections. From the beginning of myelination after birth to mul tilamellar myelin in adult animals, we observed colocalization of 04 a nd 01 label in myelin. In the oligodendrocyte soma, immunolabel was fo und primarily over Golgi cisternae. In the oligodendrocyte processes, immunolabeling was also found in the cytoplasm and along the plasmalem ma. More cytoplasmic 04 and 01 label was found in the external loop of myelin than in the internal loop. The amount of 01 and 04 label incre ased over compact myelin in proportion to the number of lamellae, but the label density per unit length of membrane remained approximately t he same in compact myelin as in oligodendrocyte plasmalemma. We did no t see a concentration gradient for either 04 or 01 label across, or al ong multilamellar myelin sheaths.