Specific neuronal localization by immunofluorescence of 10 nm filament polypeptides.

Rabbit antisera have been produced to bovine brain 10 nm filament preparations and to purified polypeptide constituents of brain 10 nm filaments. Antisera to the former preparation stain both neurons and astrocytes, whereas antisera to two polypeptides of mol. wt 155 000 and 210 000 are neuron specific. It is therefore concluded that these latter polypeptides are components of neurofilaments and the mixed staining pattern obtained with the antisera to the whole brain 10 nm filament preparation is due to the presence in this material of a mixture of neurofilaments and glial filaments which are thus biochemically distinct forms of 10 nm filament.