Hypotonic unmasking of erythrocyte receptor sites

The study reports on plasmalemmal perturbation of erythrocytes under osmotic stress. In comparison with isotonic human erythrocytes a 10 minutes incubation in 150 mosm sodium cacodylate pH 7.4 at 20 degrees C results in an increase of the anti AH P binding rate by a factor of two. 0.1 M N-acetyl galactosamine inhibits the binding of anti-AH P of both isotonic and hypotonic red cells. Contrary to isotonic mouse erythrocytes the agglutination with peritoneal murine leukocytes of hypotonic red cells is greatly enhanced provided the erythrocytes have been incubated in autologous serum. The findings are considered evidence of the unmasking of binding sites due to nonspecific rearrangement of membrane constituents.