PLANT AGGLUTININS (LECTINS) II 81 



TABLE 6-2 

 Lectins^ Inhibited by Sugars of Group 2 and 3. 



Group 2 Group 3 



Bandeiraca simpUcijoUa Parkia filicoidca 



Bauhinia spp. Lathynis latifoliiis 



Sophora japonica Lens culinaris 



Crotolaria spp. Pisuin sativiDii 



Cytisus spp. Vicia spp. 



Caragana spp. 

 Wisteria ehinensis 

 Coronilla varia 

 Erythrina spp. 

 Glycine soja 



* Extracted from plant seeds of the species listed. 



It seems clear that these plant agglutinins are not nonspecific, but 

 react with a definite chemical structure in the red cell, probably one 

 having as terminal group a sugar of group 2 or 3, as the case may 

 be. It happens that the erythrocytes of all human beings contain both 

 these particular receptors ; so therefore no individual differences are 

 found in the reactions of these lectins with human erythrocytes. 

 Further study with more complicated carbohydrates will enable us 

 to make a better guess at the detailed structure of these receptors. 

 As to the receptors with which other plant agglutinins combine we 

 have as yet no clue. 



In a systematic study of the inhibition of two "non-specific" lectins, 

 that of Ricinus communis and that of Bauhinia purpurea (dialyzed 

 free of the group 2 sugars making it A/'-specific), Boyd and 

 Waszczenko-Zacharczenko (1961) found considerable similarities, 

 but some differences. Bauhinia lectin was inhibited by sugars of 

 Makela's group 3, but Ricinus was not. It was concluded that the 

 receptors in the human erythrocyte with which these two lectins 

 combine, though similar, are not identical. Both lectins were inhil)ited 

 by "unnatural" sugars of group 4. 



In some cases the addition of an inhibiting sugar to a non-specific 

 plant agglutinin does not suppress all activity but leaves the prepara- 

 tion able to agglutinate cells of certain blood groups, thus revealing a 

 new specificity. Makela (1957) found that the agglutinin oi Bandeiraca 



