HETEROGENEITY OF MISTLETOE LECTIN CATALYTIC SUBUNITS ASSESSED WITH MONOCLONAL-ANTIBODIES

Hybridomas secreting monoclonal antibodies (MAb) against the A subunit s of toxic mistletoe lectins (ML) were produced. MAb specificity in in teraction with ML toxins was studied, and all MAb were divided into th ree groups specific for (1) MLI-A and MLII-A, (2) MLII-A and MLIII-A, and (3) for all three ML toxins. Antigenic ML determinants recognized by monoclonal antibodies MNA4, MNA9, and MTC12 were shown to be devoid of the carbohydrate moiety. A sandwich ELISA system was developed for estimating the content of each ML toxin. Structural differences of ML toxins and the nature of their heterogeneity are discussed.