Immunohistochemical localization of α and β subunits of the S-100 protein in normal human brains and brain tumors was studied by the ABC method using mouse monoclonal antibodies against each subunit. In cerebral tissues, glial cells showed positive staining for both subunits, with some neurons positive only for the α subunit.
In cerebellum, Purkinje cells and other neurons were negative for the α or β subunit, and Bergmann's cells were positive only for the β subunit. Low grade astrocytomas were strongly positive for the α and β subunits. In oligodendrogliomas and choroid plexus papillomas, the immunoreactivity of the β subunit was stronger than that of the α subunit. Medulloblastomas showed no positive staining for either subunit. Schwannomas were positive only for the β subunit. High grade astrocytomas, ependymomas and meningiomas manifested marked variability in the immunoreactivity for the α and β subunits of the S-100 protein. The evidence suggests that immunohistochemical examination of the α and β subunits of the S-100 protein in normal human brains and brain tumors may be useful in determining the histogenetic origin of brain tumors.