Comparison of Phaseolus vulgaris cultivars on the basis of isolectin differences

1. 1. The properties of lectins from 62 cultivars of the common bush bean, Phaseolus vulgaris, were examined. 2. 2. All bean extracts agglutinated rabbit and human red cells but showed no differential preference for A-, B- or O-type human red cells. 3. 3. Although most bean extracts were mitogenic, 13 bean varieties were apparently non-mitogenic when incubated with normal human lymphocytes. 4. 4. Polyacrylamide gel electrophoresis of the bean extracts in acid and sodium dodecylsulfate buffers revealed 2 major different isolectin patterns. 5. 5. Most cultivars had 5 isolectins, were strongly mitogenic, and were classified as group I beans. A second group exhibited a distinct isolectin pattern, were weakly or non-mitogenic, and were classified as group II. Finally, 2 beans with lectin electrophoretic patterns distinct from both of the above groups were classified as group III beans. 6. 6. Representative extracts from all 3 bean groups were tested with a red kidney bean isolectin L-subunit specific radioimmunoassay. The group I beans had significantly higher levels of L-subunit crossreactive protein than the group II beans while one of the group III beans had intermediate levels.