CD44 expression in human astrocytes and oligodendrocytes in culture.

CD44 is a glycoprotein present on the surface of some lymphocyte cell populations and other non-lymphoid cells, and is involved in many functions related to cell-cell and cell-matrix interactions. In this study, expression of CD44 antigen in primary neural cell cultures derived from fetal and adult human brains was investigated. In cultures processed for double immunofluorescence staining, approximately 80% of fetal astrocytes and more than 95% of adult astrocytes expressed the CD44 antigen on the cell bodies and processes; CD44 was also detected in 50-60% of adult oligodendrocytes. Neurons in fetal brain cell cultures did not express CD44 at all. Western blot analysis performed in astrocyte- and in neuron-enriched cultures confirmed the results from immunostaining and showed that the antibody against CD44 reacted with a polypeptide, of approximately 80 kD, that is present exclusively in the astrocyte-enriched cultures, but absent in neuron-enriched cultures. Our results indicate that CD44 glycoprotein is constitutively expressed in the human cells of glial cell lineage and its role is likely to be associated with normal neuroglia-mediated adhesion/recognition processes.