Species distribution of ribonucleoprotein-derived brain antigens.

Acidic glycoproteins (AP) specific for brain were derived from human brain ribonucleoprotein (RNP). Immunodiffusion against homologous antiserum confirmed the presence of three distinct antigens. Comparable materials form brain RNP of monkey and hamster contained the same three antigens; from rabbit, two identical and one related antigens. Mouse and rat material appeared to contain progressively less related antigens. Neuraminidase treatment of human AP resulted in the unmasking of two new determinants. These were also present in material from monkey and hamster; that from rabbit showed partial identity with one of these and lacked the other. Corresponding mouse and rat fractions appeared to contain one identical masked determinant, but lacked the other.