title: The effect of treatment with α-glycosidases from Bacteroides fragilis on the survival of rat erythrocytes in the circulation.
abstract: BACKGROUND
  It has been demonstrated recently that α1,3-galactosidase from Bacteroides fragilis can efficiently convert human group B red blood cells (RBC) to group O cells. In addition, in vitro data indicated that the enzymatic conversion process did not affect the physiological or metabolic parameters of the RBC. The aim of this study was to investigate the lifespan of enzyme- treated RBC in vivo in the circulation.
  
  
  METHODS
  This was an experimental, randomised study. The rat was selected as the experimental subject because it expresses α-1,3galactosyl on its RBC. The efficiency of Galα1,3Gal epitope removal from RBC treated with α1,3-galactosidase was tested before the transfusion experiment to track the survival of RBC in the circulation. The animals were divided into three groups and injected via the tail vein with native, mock-treated or enzyme-treated RBC labelled with fluorescein isothiocyanate. The survival rates of the fluorescently labelled RBC were monitored by flow cytometry.
  
  
  RESULTS
  Flow cytometry showed that α-galactosidase (0.02 mg/mL for RBC with a haematocrit of 30%) efficiently removed Galα1,3Gal epitopes from rat erythrocytes, although small amounts of remaining Galα1,3Gal epitopes were still detected. The in vivo data demonstrated that the half-life of enzyme-treated RBC was a little shorter than that of native RBC. However, the 24-hour survival fractions of native, mock-treated and enzyme-treated RBC were virtually identical. Most importantly, the enzyme-treated RBC, like the native RBC, were still detectable 35 days after transfusion.
  
  
  CONCLUSIONS
  Our results indicate that α-glycosidase treatment had little effect on the in vivo survival kinetics of RBC. These data add further support to the feasibility of translating enzymatic conversion technology into clinical practice.
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Su-Bo
authors.initials: SB
authors.lastname: Li
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Gao
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Shou-Ping
authors.initials: SP
authors.lastname: Ji
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Ying-Li
authors.initials: YL
authors.lastname: Wang
authors.affiliation: Beijing; Department of Transfusion, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, People's Republic of China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Xu
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Bao
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Shu-Guang
authors.initials: SG
authors.lastname: Tian
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Yu
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Ying-Xia
authors.initials: YX
authors.lastname: Tan
authors.affiliation: Department of Blood Biochemistry and Molecular Biology, Beijing Institute of Transfusion Medicine, Beijing, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gong
mesh_terms: D000017:ABO Blood-Group System / Q000737:chemistry; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D001441:Bacteroides fragilis / Q000201:enzymology*; D001788:Blood Grouping and Crossmatching; D002470:Cell Survival; D004353:Drug Evaluation, Preclinical; D000939:Epitopes / Q000187:drug effects; D017707:Erythrocyte Transfusion; D004912:Erythrocytes / Q000187:drug effects*; D005240:Feasibility Studies; D005434:Flow Cytometry; D005696:Galactosidases / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D008297:Male; D037121:Plant Lectins / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000017:ABO Blood-Group System; D001426:Bacterial Proteins; D000939:Epitopes; C045475:Griffonia simplicifolia lectins; D037121:Plant Lectins; D005696:Galactosidases