A reconstructed B. Fragilis-derived recombinant α-galactosidase developed for human blood type B→O conversion / 中国实验血液学杂志

This study was aimed to prepare a reconstructed B. Fragilis-derived recombinant α-galactosidase developed for human B to O blood group conversion. Based on the construction of recombinant E. Coli (DE3) which can express α-galactosidase, the inducing time and inducer concentration were optimized for high expression of α-galactosidase. Then, the expression products in supernatant were purified by cation and anion exchange column chromatography. The purified α-galactosidase was used to treat B group red blood cells in phosphate buffer (pH 6.8) for 2 hours to prepare O group red blood cells. The results showed that the optimal inducing conditions for α-galactosidase expression were IPTG 0.1 mmol/L, 37°C and 2 hours. The specific enzyme activity of purified protein increased from 0.42 U/mg to 2.1 U/mg as compared with pre-purification. And, the conditions of B to O blood group conversion were 26°C, pH 6.8 (neutral pH condition) and 2 hours. Moreover, 225 µg of the enzyme could converse 1 ml B red blood cells to O completely. It is concluded that the technology of expression and purification of recombinant α-galactosidase has been established, and the purified protein can converse B red blood cells to O completely, which means that an effective enzyme conversing B red blood cells to O has been obtained.

Progress in research on preparation of antibodies against rhesus D antigen / 军事医学科学院院刊

The RhD antigen is expressed only in human red blood cells (RBC).Its immunogenicity and clinical application are only next to ABO blood group system, and is widely used both for blood typing and prevention of hemolytic disease of the newborn. The traditional anti-Rh(D) is derived by fractionation of plasma from individuals who have been sensitized by pregnancy or transfusion, or have been deliberately immunized to produce anti-Rh(D). Because of the limited source of plasma, researchers began the study of monoclonal and recombinant antibody. Monoclonal and recombinant anti-Rh(D) antibodies may provide alternatives to the current plasma derived polyclonal IgG anti-Rh(D), but up to now,none of them have yet proved effective in humans for prevention of RhD immunity and hemolytic disease of the newborn.