It has been known for many years that there exist hemagglutinins in the seeds of many plants, particularly in those of Leguminosae, but those were in general recognized as non-specific substance to blood group antigens and, in consequence, did hardly attract attention of many researchers. In 1948, Renkonen 1) discovered firstly the natural antibodies being completely specific to blood group antigens in certain seeds and described the significance of plant agglutinin as one source of blood group antibodies. In 1953, Morgan and Watkins 2) reported the inhibiting effect of some simple sugars on the reaction between red blood cell and plant agglutinins. This important finding gave us a clue to illustrate the blood group specificity from a standpoint of chemical structure. In this decade, a number of new plant agglutinins were discovered 3-5) and partial purification of several plant agglutinins were made 6-8), but no report on the details of their chemical properties and compositions has been found. We are now working with the purification of plant agglutinin of Sophora japonica in order to get any knowledge on its chemical properties and composition and finally to elucidate the mechanisms of its selectivity to blood group antigens. In this paper, we shall present the method of partial purification of agglutinin and some of its properties.
In 1951, Watkins and Morgan 1) described that not only hog and human H substances inhibit hemagglutination of O cells by eel anti-O (H) but also that simple sugars, for example, L-fucose and its structural homologues, would exert similar effect. It was for the first time that this fact had been presented as an example of the inhibition of normal antibody by simple sugars. Further, Morgan and Watkins 2) carried out an analogous study on the inhibition of hemagglutination of plant agglutinin by simple sugars. In the preceding paper of this series 3), partial purification of the agglutinin from Sophora japonica was reported and it was revealed that our partially purified product contained anti-B, anti-C and anti-O (H) agglutinins. This paper deals with the inhibition by simple sugars on hemagglutination of our partially purified agglutinin from Sophora japonica and the results obtained are discussed mainly from a standpoint of stereochemistry of sugar.