IDENTIFICATION OF VARIANT GLYCOPHORINS OF HUMAN RED-CELLS BY LECTINOBLOTTING - APPLICATION TO THE MI.III VARIANT THAT IS RELATIVELY FREQUENT IN THE TAIWANESE POPULATION

Background: Detection of normal and Variant glycophorin electrophoreti c bands with T- and Tn-specific lectins is based on the possibility of glycophorin transformation into T or Tn antigens by simple chemical m odifications in the blot. Study Design and Methods: Human red cell mem brane proteins were fractionated by sodium dodecyl sulfate-polyacrylam ide gel electrophoresis and blotted onto nitrocellulose. The blots wer e submitted to mild acid hydrolysis (desialylation of glycophorins exp osing T antigens) and then to Smith degradation (degalactosylation of asialo-glycophorins exposing Tn antigens). The modified glycophorin ba nds were detected with biotinylated lectins and horseradish peroxidase -conjugated avidin. Results: The lectins from Artocarpus integrifolia (jacalin, anti-T/Tn), Amaranthus hybridus (anti-T), Salvia sclarea (an ti-Tn), and Vicia villosa (anti-Tn) were used. The lectins detected no rmal glycophorin bands in control and variant red cells and characteri stic additional bands in Mi.lll (GP. Mur) red cells. The sensitivity o f the method is comparable to that obtained by immunoblotting with gly cophorin monoclonal antibodies. Comparison of the electrophoretic mobi lity of normal and variant bands is helpful in the classification of g lycophorin variants. Conclusion: Lectinoblotting, based on carbohydrat e recognition, enables the detection in a red cell sample, with high s ensitivity, of all normal and variant glycophorin bands. The method ca n be also applied to other purposes, such as the identification of pol y-O-glycosylated glycoproteins in other cells or the characterization of glycosylation of glycophorins and other poly-O-glycosylated protein s.