Specific Protein of Legumes which reacts with Animal Proteins

Abstract

INTERACTIONS of proteins among themselves, except immunological reactions, can be studied by various methods ; but only in a few exceptional cases could they be demonstrated, as in the reactions of trypsin inhibitors and of agglutinins of legumes. Whether the isohæmagglutinins in man are the result of immunization or are a direct product of the participation of blood-group genes has not yet been fully settled. But the proteins which are contained in some plants and agglutinate erythrocytes cannot be a result of immunization ; they are, so to speak, natural antibodies. An antibody, however, is defined as a substance produced in response to an antigen. In this regard an antibody produced not in response to an antigen is self-contradictory. To avoid such confusion, Boyd¹ proposed the term ‘lectin’ for such substance as is produced not in response to an antigen but reacts more or less specifically with certain proteins or antigens.