Ganglioside markers GD3, GD2, and A2B5 in fetal human neurons and glial cells in culture.

Expression of ganglioside markers GD3, GD2, and A2B5 was investigated in primary cell cultures isolated from fetal human brains of 12-15 weeks' gestation by immunocytochemistry. None of neuron-specific enolase (NSE)+ neurons expressed GD3, while large numbers of NSE+ neurons expressed GD2 (72%) or A2B5 (48%). In GFAP+ astrocytes, GD3 was expressed in a small population (3%) with a high proliferative capacity. GD2 expression was observed in 20% of GFAP+ astrocytes, while A2B5 was identified in a very small number (2%) of GFAP+ astrocytes. GD2 was coexpressed in a small population (11%) of GD3+ astrocytes, while A2B5 was colocalized in more than 50% of GD3+ astrocytes. In galactocerebroside+ oligodendrocytes, GD3 expression was not observed but a small population (8-9%) expressed GD2 and A2B5. In Ricinus communis agglutinin (RCA)+ microglia, neither GD3, GD2, nor A2B5 were identified. Our results indicate that in fetal human brain cell cultures, GD3 is expressed in a small population of astrocytes, while both GD2 and A2B5 are expressed in a large population of neurons and smaller populations of astrocytes and oligodendrocytes. Our results suggest that both GD3 and A2B5, cell type-specific markers for oligodendrocyte-type 2 astrocyte progenitor cells in the rat central nervous system, could not be utilized as valid markers for glial precursor cells in fetal human brain cell cultures.