Lectins: an important role in blood bank laboratories

Abstract

Lectins were discovered 137 years ago, predating Landsteiner’ s discovery of ABO blood group system. In 1888, Stillmark studied the toxicity of castor beans (Ricinus communis) on red blood cells by saline extracts. He observed these seed extracts caused the hemagglutination and noted to this event is the discovery of the first lectin. At that time the blood group was unknown until 1900 Landsteiner discoveries ABO blood group. This discovery made the beginning of lectins research in the field of immunohematology. In 1926-1927 Marcusson-Begun and Sievers attempted to find blood group specific lectins that extracted plants seeds but were unsuccessful. During the 1940s to 1950s, considerable efforts were made to identify lectins with specificity toward blood group antigen on the surface of red blood cells. A substantial number of research articles on this subject were published during that period. In 1945 Boyd discovered lectins could be blood group antigens specific non-immune origin. He found anti-A activity when saline extracted lima bean (Phaseolus lunatus, syn. Limensis) but he reported it in 1949. At the same time, Reguera reported his investigated results on 262 varieties of plant seeds and Renkonen reported anti-A activity in Tufted vetch (Vicia cracca) seeds and anti-H lectins in 3 plant seeds Scottish laburnum (Laburnum alpinum), Broom (Cytisus sessilofolius), and Asparagus pea (Lotus tetragonolobus same species Psophocarpus tetragonolobus). Common gorse (Ulex europaeus) present anti-H finding by Cazal and Laularie and grass-like vetch (Vicia graminea) present anti-H discovered by Ottensooser and Silberschmidt. Bird reported anti-A₁ activity in extract seeds of Horse gram (Dolichos biflorus). Lectins found in many species are not only in plants, but also in animals, fungi, bacteria and viruses. In plants, lectins present in leguminous seeds or fruit flesh and in animals there are various invertebrates, 1888 Camus found in snail and 1903 Noguchi found in horseshoe crab. There are about 500 plant species that contain hemagglutination lectins that can specifically bind to sugar residues blood group antigens on red blood cell membrane. A, B and H antigens of ABO blood system are found both on red blood cells membrane and body fluids of individual secretors except the Bombay phenotype (O_h) and they are always anti-H in their serum. Hemagglutinating activity of seed extracts are inhibited by A, B and H soluble substances in body secretions fluid such as saliva, breast milk and mucus. ^{1, 2, 3} The objective of this article is to present the application of hemagglutination lectins as reagents for the identification of blood group antigens on red blood cell membranes and in body secretions. The following section will present lectins with specificity toward various blood group antigens, as outlined below.