Modulation of antigenic expression in cultured adult human oligodendrocytes by derivatives of adenosine 3',5'-cyclic monophosphate.

Oligodendrocytes were isolated from adult human brains obtained at autopsy by enzyme treatment - Percoll density gradient centrifugation, and grown in culture. During the first week in vitro, these cultures consisted of an enriched population (93-98%) of galactocerebroside-immunoreactive oligodendrocytes. After 2 weeks and onward, a large number of GFAP-positive astrocytes and glial cells doubly positive for galactocerebroside and GFAP markers was found among the oligodendrocytes. When these cultures were exposed to dibutyryl cyclic AMP, 8-bromocyclic AMP and RO-1724, an inhibitor of cyclic nucleotide phosphodiesterase, for 4-14 days, the majority of cells returned to express oligodendrocytic phenotype. These findings suggest the presence of heretofore unidentified "transitional" or "bipotential" glial cells in human brains that express both oligodendrocytic and astrocytic phenotypes, and the regulatory role of cyclic AMP derivatives which may induce a stable antigen expression in oligodendrocytes.