CD15-CONTAINING GLYCOCONJUGATES IN THE CENTRAL-NERVOUS-SYSTEM

CD15-containing glycoconjugates have a common trisaccharide residue, 3 -fucosyl-N-acetyllactosamine, which can be recognized by a panel of mo noclonal antibodies. Immunohistochemical studies revealed a widespread distribution of CD15 in several epithelial non-neural tissues as well as in the CNS. In the mature mammalian brain CD15-containing glycolip ids and glycoproteins are constantly present in astrocytes, whereas ol igodendrocytes and particular subpopulations of neurons are variably i mmunostained. CD15 immunoreactive astrocytes are spatially distributed in some brain regions, which points to specialized functions of astro glial subpopulations. The expression of CD15 follows a timely ordered pattern during the development of glial cells and neurons of certain b rain areas, such as the human and rat cerebellum and the mouse visual system. During morphogenesis, CD15 may exert either growth-promoting o r growth-repulsive activities to guide cell migration. In CNS lesions altered expression patterns of CD15 may occur. For example, in human g liomas the staining intensity for CD15 inversely correlates with the g rade of malignancy. In degenerative brain diseases reactive astrocytes may reveal an increased labelling intensity on their cell surface as well as an abnormal cytosolic accumulation of the epitope. The functio nal significance of CD15 in the CNS is not exactly known yet. The carb ohydrate could be involved in cellular adhesion and/or as receptor mol ecule in signal transduction pathways, as has recently been demonstrat ed for leukocyte-platelet or leukocyte-endothelial cell interactions.