Ouchterlony precipitin tests give visual evidence that extracts from Lotus
tetragonolobus contain two different lectins. In addition to the H antigen, Lotus identifies
another antigen, called the L antigen, which is not the A, B, Le^a, Sd^a, I or SC(1) saliva antigen
and has been found in variable strength in secretor and nonsecretor saliva of individuals
of all ABO blood groups. The L antigen is part of a cathode migrating glycoprotein.
Sugar inhibition studies reveal that the terminal sugars are the same as for the H and Le^a
antigens, the presumable difference being that L-fucose is attached to a different site. The
L antigen is absent in the saliva and red cells of the Bombay type, but red cells of all other
individuals absorb both lectins from Lotus extract.