“…The following scheme relating Tn, T and MN antigens has been proposed by Springer Sturgeon et al [14] and others [6,7,9,26,36] have clearly shown that Tn activation is characterized by exposure of the 'A-like' receptors AHm, ADb and AH^, as judged by serological studies with anti-A reagents from human sera (AH,,,), Dolichos biforus (ADb) and Helix pomatia (AHp). Moreover, these 'A-like' receptors are distinguished by their sensitivity to protease treatment since AH,,,, ADb and Tn [6,36] are destroyed by papain and ficin while AHP is not [14].…”