title: B to O erythrocyte conversion by the recombinant alpha-galactosidase.
abstract: BACKGROUND
  Human group O red blood cells have great benefit in specialized transfusion areas such as armed conflict and natural calamity. The group B antigen differs structurally from group O antigen only by the addition of one terminal alpha-linked galactose residue. In this study we aimed to remove the terminal galactose from group B red blood cell to get group O red blood cell.
  
  
  METHODS
  alpha-galactosidase cDNA was cloned by RT-PCR from Catimor coffee beans grown on Hainan Island of China. The vector for alpha-galactosidase cDNA expression was constructed and transferred into Pichia pastoris cells by electroporation. The transgenic cells were cloned by fermentation and the recombinant alpha-galactosidase was purified by ion exchange chromatography. After studying the biochemical characters of alpha-galactosidase, we have used it in converting human erythrocytes from group B to group O.
  
  
  RESULTS
  The purity of recombinant alpha-galactosidase was higher than 96%, which was thought to be suitable for the use of blood conversion. Enzymatically converted human group O red blood cells (ECHORBC) exhibited membrane integrity, metabolic integrity, normal cell deformation and morphology. There were no coagulation between ECHORBC and any group of human blood. The ECHORBC will keep normal structure and function for a period of 21 days at 4 degrees C in monoammoniumphosphate nutrient solution. Experiments with Rhesus monkeys and gibbons showed that transfusion of enzymatically converted erythrocytes was safe.
  
  
  CONCLUSIONS
  ECHORBC can be easily obtained from group B red blood cell by alpha-galactosidase digestion. This study suggests that ECHORBC could be transfused to patients safely and efficiently.
authors.affiliation: Institute of Blood Transfusion Medicine, Academy of Military Medical Sciences, Beijing 100850, China. zhangyp@nic.bmi.ac.cn
authors.forename: Yang-pei
authors.initials: YP
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Gong
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Bao
authors.forename: Hong-wei
authors.initials: HW
authors.lastname: Gao
authors.forename: Shou-ping
authors.initials: SP
authors.lastname: Ji
authors.forename: Ying-xia
authors.initials: YX
authors.lastname: Tan
authors.forename: Su-bo
authors.initials: SB
authors.lastname: Li
authors.forename: Li-li
authors.initials: LL
authors.lastname: Li
authors.forename: Ying-li
authors.initials: YL
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.forename: Li-juan
authors.initials: LJ
authors.lastname: Xu
authors.forename: Shu-guang
authors.initials: SG
authors.lastname: Tian
authors.forename: Zhi-xin
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Qiu-shuang
authors.initials: QS
authors.lastname: Lü
authors.forename: Yan
authors.initials: Y
authors.lastname: Qiu
authors.forename: Jian-shi
authors.initials: JS
authors.lastname: Bai
authors.forename: Ji-ting
authors.initials: JT
authors.lastname: Chen
mesh_terms: D000017:ABO Blood-Group System / Q000145:classification / Q000378:metabolism*; D000818:Animals; D001803:Blood Transfusion; D003001:Cloning, Molecular; D003069:Coffee / Q000201:enzymology; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D008253:Macaca mulatta; D011786:Quality Control; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000494:pharmacology; D000519:alpha-Galactosidase / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D000017:ABO Blood-Group System; D003069:Coffee; D011994:Recombinant Proteins; D000519:alpha-Galactosidase