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| 1 | Human RBCs blood group conversion from A to O using a novel α-N-acetylgalactosaminidase of high specific activity显示文摘α-N-acetylgalactosaminidase (αNAGA) can convert group A human red blood cells (RBCs) to group O. One novel αNAGA gene was cloned by PCR from Elizabethkingia meningosepticum isolated from a domestic clinical sample. Pure recombinant αNAGA was obtained by genetic engineering and protein purification with a calculated molecule of 49.6 kD. αNAGA was selective for terminal α-N-acetylgalacto-samine residue with a high specific activity. αNAGA could completely remove A antigens of 1 U (about 100 mL) group A1 or A2 RBCs in 1 h at pH 6.8 and 25℃ with a consumption of 1.5 or 0.4 mg recombinant enzyme. Enzyme-converted group A RBCs did not agglutinate after being mixed with monoclonal anti-A or sera of groups A,B,AB and O. Other blood group antigens except ABO had no change. FCM analy-sis showed that A antigens and A1 antigens disappeared while H antigens increased. It indicated that αNAGA successfully converted human blood group A RBCs to universally transfusable group O RBCs without the risk of ABO-incompatible transfusion reactions. This αNAGA was suitable for producing universal RBCs to increase clinical transfusion safety,improve the RBCs supply,and to decrease transfusion cost and support transfusion service in case of emergency. | YU ChengYu XU Hua WANG LiSheng ZHANG JianGeng ZHANG YangPei | 2008 | Chinese Science Bulletin2008，53，13： | 5 |
| 2 | Rudimentary study on humanization of porcine red blood cells: Enzymatic removal of galactose-α1,3- galactose antigen from porcine red blood cell显示文摘The serological and biochemical characteriza-tion of porcine red blood cells (pRBCs) are similar to human red blood cells. Porcine erythrocytes are considered as an alternative source for human blood transfusion. But there exist galactose-?,3-galactose antigens (Gal?,3Gal?, 4GalNAcR, abbreviated 酖al antigen) on pRBCs, which can induce anti-aGal antibodies in human serum. The aGal epitopes are the major antigen responsible for hyperacute rejection in xenotransfusion. In this study, recombined soy-bean -galactosidase (rS?GalE) was used to remove the aGal antigens from pPRCs for humanization. The results showed that aGal antigen was cleared by rS?GalE and the structure and function of rS?GalE treated pRBC were normal. | WANG Jiexi GAO Xin BAI Yan REN Huiming TAN Yingxia ZHANG Yangpei | 2003 | Chinese Science Bulletin2003，48，4： | 2 |
| 3 | Down-regulation of αGal epitopes by co-transfection of α1,3-galactosidase gene and α1,2-fucosyltransferase gene显示文摘The polycarbohydrate structure of Galα1- 3Galβ1-4GluNAc-R (known as αGal epitopes of xenoantigen), produced by α1-3-galactosyltransferase (α1,3-GT) in the course of animal development, is the major xenoantigen on the cell surface of porcine which causes hyperacute rejection in pig-to-human xenotransplantation. Alpha-1,3-galactosi- dase (AGL), a hydrolytic enzyme, can remove the terminal α-1,3-galactosyl from the Galα1-3Galβ1-4GluNAc-R struc-ture resulting in cleaning αGal epitopes from the porcine cells. Alpha-1,2-fucosyltransferase (HT) can modify the sur-face carbohydrate phenotype of porcine cells, bringing about reduction of αGal epitopes expression. In this study, human AGL and HT gene were co-transfected to porcine fetal fibro-blast (PFFb) in equimolar concentration to reduce the xeno-antigen. Gene and protein of hAGL and HT were both de-tected to express at high level by RT-PCR and Western blot, respectively. There was an 84% reduction in αGal xenoanti-gen and an 82% increase in H antigen as assayed by flow cytometry in the AGL and HT gene co-transfected PFFb. The number and morphology of transgenic PFFb chromosome were normal. Findings indicate that Galα1-3Gal epitopes of PFFb could be down regulated by AGL and HT co-transfec- tion without deleterious effects on the chromosomal profile of the transgenic cell. | GONG Feng ZHANG Yangpei JIA Yanjun WANG Yingli TAN Yingxia TIAN shuguang | 2005 | Chinese Science Bulletin2005，50，23： | 0 |
| 4 | Aberrantly Methylated MGMT,hMLH1 and hMSH2 in Tumor and Serum DNA of Gliomas Patients显示文摘OBJECTIVE This study is to investigate the prevalence ofpromoter CpG island methylation of O^6-methylguananine-DNAmethyltransferase (MGMT), mismatch repair genes (hMLH1 andhMSH2) in both tumor and serum samples of gliomas.METHODS Methylation-specific PCR (MSP) was employed todetect promoter CpG island methylation of the MGMT, hMLH1and hMSH2 genes in 39 samples taken from surgery and 32samples of pretreatment serum all from the patients with gliomas.RESULTS Promoter CpG island methylation of MGMT, hMLH1and hMSH2 was detected and the results were 46.2%, 10.3% and20.5%, respectively in tumor DNA of the cases with gliomas,and 40.6%, 9.4% and 18.8%, respectively in serum DNA of thecases. The methylation pattern in primary tumor and serum wasfound to be concordant in matched tissue and serum samplesof 21 patients. In the cases with positive result of methylationfor MGMT, hMLH1 and hMSH2 in tumor tissues, the results ofdetection for those in the paired serum sample were 77.8% (7/9),66.7% (2/3) and 75.0 % (3/4), respectively. False positive resultswere not obtained in any of the patients who did not exhibitmethylation. No association was found between the promotermethylation of MGMT, hMLH1, and hMSH2 genes in primarygliomas and gender, age, localization, grade of malignant or tumorstage.CONCLUSION Promoter CpG island methylation is a frequentevent in gliomagenesis. Methylation analysis appears to bea promising predictive factor of the prognosis for the gliomapatients treated with alkylating drugs and a noninvasive tumormarker in serum DNA. | Changqing Zheng Shouping Ji Feng Gong Anming Li Junli Tai Subuo Li Yingli Wang Hongyu Chang Hongwei Gao Yangpei Zhang | 2009 | Chinese Journal of Clinical Oncology2009，6，1： | 0 |
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