A new anti-B lectin

Use of lectins in immunohematology

Lectins are carbohydrate binding proteins present in seeds of many plants, especially corals and beans, in fungi and bacteria, and in animals. Apart from their hemagglutinating property, a wide range of functions have been attributed to them. Their importance in the area of immunohematology is immense. They are used to detect specific red cell antigens, to activate different types of lymphocytes, in order to resolve problems related to polyagglutination and so on. The introduction of advanced biotechnological tools generates new opportunities to exploit the properties of lectins, which were not used earlier. Stem cell research is a very important area in transplant medicine. Certain lectins detect surface markers of stem cell. Hence, they are used to understand the developmental biology of stem cells. The role of various lectins in the areas of transfusion and transplant medicine is discussed in detail in this review.

Composition and immunochemical properties of glycoproteins with anti-B agglutinin activity isolated from Euonymus sieboldiana seeds

Five major glycoproteins with anti-B agglutinin activity were isolated from seeds of Euonymus Sieboldiana by a procedure based on precipitation with ammonium sulphate, Sepharose 4B gel filtration, CM- and DEAE-Sepharose chromatography and Sephacryl S-200 gel filtration. The purified glycoproteins each gave a single symmetrical peak on Sephacryl S-200 gel filtration with elution volumes corresponding to molecular weights of approximately 15,000 to 130,000, each forming a single precipitin line on gel diffusion plates with anti-E. Sieboldiana antibody. These anti-B glycoproteins were rich in acidic amino acids without cysteine and methionine and contained about 8--36% carbohydrate, of which galactose, arabinose and glucose were the predominant sugars, with small amounts of glucosamine, rhamnose, fucose, xylose, mannose and ribose. The most anti-B active lectin agglutinated human B red blood cells at a concentration of 2 micrograms/ml and was strongly inhibited by melibiose. The three other lectins with anti-B agglutinin activity, however, were not inhibited by any galactose-containing glycosides.

Anti-B activity of a lectin coexistent with blood group H-like substance in seeds of Euonymus sieboldiana

Euonymus Sieboldiana seeds possess a lectin for human erythrocytes with anti-B specificity. Lectin fractions with strong agglutinating activity were separated by ammonium sulphate precipitation from blood group H-like substance, which is coexistent in the same seeds. The lectin has properties resembling a complete agglutinin, being non-dialysable, inactivated by heat treatment at 70 degrees C and specific for D-galactoside.

Lectins in extracts of certain Polygonaceae seed precipitate animal and human serums

Seeds of four species of Polygonaceae were tested for lectins that precipitate human and animal serums. Rumex crispus, Polygonum convolvulus, and Polygonum pennsylvanicum developed specific precipitate bands on double diffusion on agar gel plates. These bands were enhanced and increased in number when extracts were tested against serums from patients with certain diseases. When tested against lyophilized serum, no precipitate bands developed. The active substance cannot be dialyzed through cellulose membrane against running tap water for 16 hours, and it is heat stable. Extracts from Fagopyrum esculentum developed no precipitate bands.