Immunofluorescent detection of CD15-fucosylated glycoconjugates in primary cerebellar cultures and their function in glial-neuronal adhesion in the central nervous system

Expression of CD15 antigen (also referred to as stage specific embryonic antigen, SSEA-1, or Lewis(x)) was analyzed in cerebellar cultures prepared from seven day old rats by double immunostaining with anti-CD15 mAb7A and cell-specific antibodies to glial fibrillary acidic protein (GFAP) and Vimentin. The immunocytochemical data suggest that the expression of CD15 antigen is restricted to some GFAP-positive cells with fibroblast-like morphology characteristic of Type-1 astrocytes. In order to explore the involvement of CD15 antigen in glial-neuronal interactions, the ability of mAb7A antibody to interfere with granule cell adhesion to a monolayer of astrocytes was tested in comparison with anti-GFAP. The adhesion of cerebellar granule cells to astrocytes, as determined by the number of bound cells, was decreased by 39% following preincubation with mAb7A. Anti-GFAP did not alter cell adhesion, indicating the specificity of the anti-CD15 antibody effect. These results are consistent with the hypothesis that CD15 antigen participates in glial-neuronal interactions in the developing cerebellum. Furthermore, it may be speculated that the modulation of cell-surface CD15 expression contributes to the altered strength of glial-neuronal interaction, facilitating cell migration and differentiation.