Antigenic constituents of basic proteins from human brain.

1. A minimum of three distinct basic proteins have been chromatographically separated from a neutral, low ionic strength extract of human grey matter, using a discontinuous eluant series. 2. These chromatographic subfractions have been characterized by gradient elution chromatography and each subfraction analysed for distinct antigenic characteristics. 3. Evidence was adduced for the presence of a minimum of three distinct basic protein antigens, all of which may be specific to human brain but not to human liver. None of them appear to be human serum proteins.