LOCALIZATION OF THE CD15-EPITOPE IN THE INNER-EAR OF THE DEVELOPING MOUSE

The expression of the 3-fucosyl-N-acetyl-lactosamine (CD15) epitope du ring the embryonic development of the mouse inner ear has been immunoh istochemically studied on paraffin sections from day 8.5 to day 19 of gestation. Consecutive steps of morphological development are accompan ied by up- and down-regulation of CD15 expression and changing cell pa tterns. Expression levels are reduced once structural maturation has b een accomplished. Since CD15 has been described as a determinant that is expressed during critical developmental steps, it is speculated tha t the changes in the epitope expression in the inner ear reflect relev ant stages of differentiation. This system may thus serve as a model f or understanding inner ear development.