Epiglycanin-immunoreactive glycoproteins in mouse fetal tissues and fetal cells in culture

Fetal tissues from time-pregnant female A/J mice of 16- and 19-day pregnancies and from neonates 1 day after birth, as well as from fetal cells in culture, absorbed significant amounts of anti-epiglycanin antibody. Detergent-solubilized glycoproteins, with epiglycanin activity, from fetal tissues and cells were separated by polyacrylamide gel electrophoresis, and the protein bands electroblotted onto a nitrocellulose gel. After the antigens were labeled with rabbit anti-epiglycanin antiserum and [125I]epiglycanin, autoradiography revealed two major bands containing the antigenic determinant at Mr 90,000 and 82,000. Bands of similar molecular weights, but with no demonstrated immunologic cross-reactivity, were observed by fluorography, if intact cells prior to solubilization were labeled by galactose oxidase followed by sodium borotritiide. Immunoreactive epiglycanin activity could be destroyed by Pronase, endo-N-acetyl-alpha-D-galactosaminidase (Diplococcus pneumoniae), or periodate oxidation. Activity was enhanced with neuraminidase. The spleen, liver, or erythrocytes from adult A/J mice did not possess the antigen, but incubation of adult spleen or liver with neuraminidase (Vibrio cholerae) exposed the epitope.