A monoclonal antibody to Schwann cell surface membrane recognizes a cAMP inducible epitope

A monoclonal antibody to the surface membrane of rat Schwann cells was generated. This antibody bound to Schwann cell surfaces but not to fibroblasts in mixed neonatal sciatic nerve cultures. It did not bind to cells in newborn rat brain or corpus callosum cultures that contained oligodendrocytes, astrocytes, fibroblasts and neurons. The target antigen for this monoclonal antibody disappeared from Schwann cell surface after 5 days in culture. At this time, addition of 10^-3 M 8-bromo cyclic AMP or 10^-3 M dibutyryl cyclic AMP resulted in the reappearance within 2 days, of the target antigen on Schwann cell surface membrane. The reappearance of this epitope parallels that of surface galactocerebroside on Schwann cells when incubated with cAMP analogues. Re-expression of the target antigen for this monoclonal antibody in the presence of cAMP is evidence that cAMP may be a signal for synthesis of a variety of myelin molecules and as such could be a signal for myelination of axons by Schwann cells.