HUMAN BLOOD GROUP A; SPECIFIC AGGLUTININ OF THE BUTTER CLAM SAXIDOMUS GIGANTEUS.
Saline extracts of the butter clam Saxidomus giganteus specifically agglutinated human red blood cells of phenotypes A(1) and A(1)B. The agglutinin was completely absorbed by A(1) and A(1)B cells, partially absorbed by A(2) cells, and unaffected by B and O cells. Of 21 sugars tested, only N-acetyl-d-galactoseamine and N-acetyl-d-glucoseamine inhibited the agglutinin.