A glycoprotein was solubilized from sheep erythrocyte membranes with hot aqueous ethanol. The glycoprotein was purified by phosphocellulose chromatography, ethanol precipitation, lipid solvent extraction, and DEAE chromatography. In water solution the glycoprotein existed as globular aggregates with a diameter of 7.1 ± 2.2 nm. In the presence of sodium dodecyl sulfate, 80% of the material exhibited a subunit m.w.(app) of 27,000. Approximately 10% of the material had a m.w.(app) of only 9000 and another 10% had a m.w.(app) of 35,000. All three fractions were reactive with Paul-Bunnell heterophile antibody from the sera of patients with infectious mononucleosis and with Limulus polyphemus lectin. These activities were destroyed by neuraminidase treatment. Complete inhibition of the rosetting of sheep red blood cells by 4 x 105 human peripheral blood lymphocytes was seen at 100 to 200 μg glycoprotein/ml. Neuraminidase-treated glycoprotein was not inhibitory. Pronase-derived sialoglycopeptide was inhibitory. Most likely, the receptor for lymphocytes resides in the carbohydrate portion of the glycoprotein. By using 125I-glycoprotein, binding studies were carried out that yielded an estimate of approximately 2 x 105 binding sites for sheep erythrocyte glycoprotein per lymphocyte. Purified glycoprotein contained 44.4% amino acid. Carbohydrate components and their molar ratios were sialic acid (1.0):galactose (1.0):N-acetylglucosamine (1.3):N-acetylgalactosamine (1.2).
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Immunology|
|State||Published - Apr 5 1982|
ASJC Scopus subject areas
- Immunology and Allergy