Differential Expression of Cell Surface Antigens and Glial Fibrillary Acidic Protein in Human Astrocytoma Subsets1

We have characterized five distinct cell surface antigens of human astrocytomas and correlated their expression with the expression of glial fibrillar) acidic protein (GFAP) and four previously defined cell surface markers of astrocytomas. One of the newly studied antigens, A4, which was originally detected on rat central nervous system (but not peripheral nervous system) neurons, is expressed on GFAP* human astrocytoma cells, but not on GFAP" astrocytomas or a wide range of other neuroectodermal, epithelial, and hematopoietic cells. Antigens F19 (M, 140,000/ 90,000 glycoprotein) and F24 (M, 90,000 glycoprotein) also show re stricted distribution and are expressed on subsets of neuroectodermal and mesenchymal cells. Antigens G253 (M, 95,000 glycoprotein) and S5 (M, 120,000 glycoprotein) are more widely distributed on the cultured cell panel. The distribution of these antigens was determined on a series of 22 astrocytoma cell lines and in normal brain tissue and the results were compared with the distribution of 5 additional glial cell markers: GFAP and cell surface antigens AOIO (A/r 110,000 glycoprotein); AJ8 (M, 100,000 glycoprotein); LK26 (M, 35,000 glycoprotein); and Thy-1. Distinct patterns of expression on cultured astrocytomas and in neural tissues were identified for all antigenic systems studied, and cell surface expression of antigen A4 was found to correlate closely with GFAP phenotype of cultured astrocytomas. The antigens described in this study provide new markers to study normal glial differentiation and to correlate the phenotypes and biological behavior of distinct subsets of astrocyto mas.