In vitro differentiation of neural progenitor cells from prenatal rat brain: Common cell surface glycoprotein on three glial cell subsets

Glial progenitor cell differentiation and cell lineage relationships during brain development are complex hierarchical processes depending on genetic programming, cell‐cell interactions, and microenvironmental factors. The identification of precursor cell‐specific antigens provides a tool for the study of both normal development and deviations from lineage‐specific differentiation associated with malignant transformation. Monoclonal antibody (mAb) RB13‐6 recognizes a 130‐kDa cell surface glycoprotein (gp130RB13‐6) expressed by a subset of 9OAcGD3‐positive glial precursor cells scattered in the rat neuroepithelium on prenatal day (PRD) 13. During prenatal development the fraction of gp130RB13‐6‐positive fetal brain cells (FBC) decreased from about 18% (PRD 14) to about 1.5% (PRD 22), coinciding with increasing fractions of more mature cell types, as indicated by the elevated expression of p24RB21‐15, another cell surface determinant specified by mAb RB21‐15 (Kindler‐Röhrborn et al.; Differentiation 30:53–60, 1985) and other neural cell type‐specific markers. Accordingly, gp130RB13‐6‐positive precursor cells were localized in the ventricular zones throughout brain development. Concomitant with their formation and in the adult rat brain, ependymal layers lining the ventricular surface, choroid plexus, and the leptomeninges were intensely labeled by anti‐gp130RB13‐6 mAb. As visualized by confocal laser scanning microscopy of FBC cultures from PRD 13, gp130RB13‐6 was coexpressed with the RC1 antigen by progenitor cells morphologically resembling radial glia cells. In addition, a very small subpopulation of astrocytes coexpressing gp130RB13‐6 and glial fibrillary acidic protein (GFAP;