Publications by authors named "Yong-Zhi Xi"

Objective: To study the allelic characteristics of "homozygote" resulted from low resolution genotyping of HLA-Cw locus and to provide more precise typing data for clinical transplantation.

Methods: Forty three related allogeneic hematopoietic stem cell transplantation(allo-HSCT) donors and patients with HLA-Cw * 03, Cw * 07 homozygote, which were the most common gene groups in Chinese population, identified by low resolution genotyping level were retyped by high resolution PCR-SSP genotyping method, and three dimensional structure modelling was also made by using a solely developed HLA three-dimensional matching software (HLA strucMark version 1.0) to evaluate the effect of differences between two mismatched alleles and its relationship with GVHD occurrence.

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The aim of this study was to investigate the parameters of gene frequencies, haplotype frequencies and linkage disequilibrium of HLA-A, -B, -Cw in HLA classical I loci for Chinese Han population. HLA-A, HLA-B and HLA-Cw loci were genotyped in 1014 unrelated China people using low resolution PCR-SSP typing method, and their genetic parameters were analyzed by statistic methods. The results indicated that among all the detected HLA-I genes, A*02 (0.

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In order to investigate the expression of heavy chain of HLA-B * 2705 in prokaryotic system and identify its activity, the extra-membrane gene fragment of HLA-B * 2705 was amplified from full-length HLA-B*2705 cDNA by PCR and cloned into pGEM-T vector. After identification by sequencing, the prokaryotic expressing vector pET32a (+)-B * 2705 was constructed. The antigenic activity of expressed protein was identified by Western blot and antibody blocking reaction.

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Objective: To investigate the therapeutic effect of gene vaccine encoding chicken collagen type II (CC II) on collagen-induced arthritis (CIA) comprehensively.

Methods: Three groups (CIA) were given a single intravenous injection of plasmid pcDNA-CCOL2A1 (20 microg/kg, 200 microg/kg, 400 microg/kg) respectively and one group (CIA) was injected 200 microg/kg pcDNA3.1 as a control.

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Objective: To analyze the distribution of genes in HLA-Cw locus from Han population of China in a large scale, and to provide basic data for further study on the genetic characteristics of HLA-Cw locus of this population.

Methods: Totally 1285 unrelated Chinese Han individuals were typed by PCR-SSP, and statistics was utilized to investigate the distribution rules of detected genes.

Results: Twenty-three HLA-Cw alleles were identified in Chinese Han population, out of them HLA-Cw*01, *03, *07 and *08 were the commonest genes, which accounted for frequencies of 0.

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Objective: To investigate the recombination event occurring between HLA-B and -Cw loci discovered in a family of Chinese Han nationality with an acute myeloid leukemia (AML) patient.

Methods: Peripheral blood samples were collected from a Chinese man with M5 type AML, aged 39, and his healthy wife and daughter, all of Han nationality. HLA class I (-A, -B, and -Cw) and II (-DRB1 and -DQB1) alleles were typed by both low and high resolution PCR with sequence specific primers (PCR-SSP) and sequence-based typing (SBT).

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This study was aimed to establish downstream purification procedure by which the protein of interest can be purified to higher purity rapidly and efficiently. The different combinations of various purification strategies, methods and conditions were compared, including reversed phase chromatography, metal chelating chromatography, anion exchange chromatography, blue dye affinity chromatography, filtration chromatography and so on. The results showed that in reversed phase chromatography, isolated protein of interest was denatured and precipitated immediately after chromatography because methanol or acetonitrile were adopted as the organic phase.

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Understanding with greater clearness the characteristics of recombination within the human leucocyte antigen(HLA) is of deep significance to gaining an insight into the evolutionary process of shaping HLA allelic diversity and ultimately the human resistance against diverse pathogens. Family studies and statistical analysis of recombination have provided estimations of recombination fractions across the major histocompatibility complex and have identified the potential recombination hotspots. Other characteristics such as haplotype specificity and sequence motifs have been intensively studied.

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Objective: To study the expression of recombinant human SCF-TPO fusion protein and its biological function.

Methods: Four primers were designed according to known sequences of TPO and SCF. The functional amino acid domains of TPO and SCF were amplified by RT-PCR from fetus hepatocytes, respectively.

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The objective was to identify some biochemical and physical properties for fusion protein IL6D24-PE40KDEL. Edman degradation, SDS-PAGE, peptide mass fingerprinting, Western blot and MTT were used for identification of the protein. The results showed that the sequence of N-terminus is Met-Ile-Asp-Lys-Gln-Ile, Met was added because of prokaryotic expression system; Western blot revealed that the purified protein could react with IL6 and PEA antibody.

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Aim: Design, construction, expression in E coli and protein characteristics prediction of bimolecular thrombopoietin (T-T) with more stability, efficiency, and lower toxicity.

Methods: The expression vectors of TPO and T-T, pET32 a(+)/TPO and pET32 a (+)/T-T, had been constructed by molecular cloning methods. Then, they were expressed in host bacterium.

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Objective: A novel recombinant interleukin6-Pseudomonas exotoxin fusion protein, having targeted cytotoxicity for leukemic cells highly expressing IL6R has been molecularly designed and constructed in this study.

Methods: Firstly, REDLK at C-terminus of Pseudomonas exotoxin PE40 was replaced with KDEL using point mutagenesis technology. Secondly, a cDNA encoding interleukin-6 devoid of N-terminal 24 amino acids [IL6D24] was fused to 5' terminus of PE40KDEL DNA by the method of gene splicing by overlap extension, which could generate recombinant IL6D24-PE40KDEL and IL6D24-Linker-PE40KDEL fusion genes.

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Objective: To establish and stabilize a new HLA typing strategy, reference strand mediated conformation analysis (RSCA), and to conform its advantages by using HLA-A as target gene.

Methods: 20 standard DNA samples from international RSCA cooperative team were used to establish and stabilize RSCA. 84 DNA samples of related hematopoietic stem cell transplant donor-recipients were extracted from peripheral blood cells.

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An inevitable trend for the development of new treatment of leukemia is to use targeted strategy. IL-6/IL-6R is important one of the cytokine receptor targeted treatment systems. Many malignant cells, including multiple myeloma, prostate carcinoma and leukemia etc.

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The purpose of the research is to provide a new standard for matching of HLA three-dimensional structure, and summarize the major permissible mismatch and immunogenic mismatch antigens. The molecular modeling method was used to create HLA molecular structures by Swiss Model Server, and the comparison of the differences among the alleles was done by SPDV software with the function of iterative magic fit. The results were recorded by relative mean square deviation (RMSD, nm).

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In order to confirm the reasonability of designed recombinant exotoxin B7-1-Linker-PE40 and B7-2-Linker-PE40, their molecular biology characteristics, such as flexibility, antigenicity, hydrophilicity, epitope and secondary structure, were predicted by using a computer software GOLDKEY. It had been found that the recombinant fusion exotoxin had kept the epitope characterstics of B7-1, B7-2 and PE40, and had not got new epitope, and the antigenicity in flexible linker was extxemely low. The linker inserted in the recombinant fusion exotoxin had low epitope, low antigenicity and high flexibility.

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Cytokines such as erythropoietin (EPO) and thrombopoitein (TPO) and so on, which stimulate hematopoiesis, can regulate self-renewal, proliferation, differentiation, maturation and programmed cell death of hematopoietic cells through specifically binding to surface receptors. Recently random phage display peptide libraries and other screening methods have been used to isolate mimetic including small peptides and non-peptides molecules, which can mimic the same effects as cytokines, such as EPO and TPO, and demonstrate the similar potency and activity as EPO and TPO in a panel of in vitro biological assays and in animal experiments. These approaches are critical to further research of interactive mechanisms between cytokine and receptor, receptor activation and rational design of other desired cytokine mimetic.

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To probe into the expression of alpha subunit for IL-6R at both mRNA and protein levels in human leukemic cells and to discuss its implication in targeted treatment for leukemia with recombinant IL-6-PE40 exotoxin fusion protein mediated by IL-6/IL-6R system, semi-quantitative RT-PCR, sequencing and FCM were used to analyze the gene and protein expression levels of alpha subunit for IL-6R in leukemic cells. Our results showed that not only mRNA but also protein of alpha subunit for IL-6R are highly expressed in the myelogenous leukemic cell lines, the relative expression levels of mRNA were KG-1(1.22) > (1.

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To study the pathogens incidences in cord blood and the efficiency of different detective methods, 60 samples were drawn and reserved from collected and processed cord blood, respectively. The BACTEC 9050 system, improved Martin/thioglycollate broth (22 degrees C) and thioglycollate broth (35 degrees C) were employed to detected bacteria (including fungus) at the same time. Two hundred and six cord blood serum samples were used to detect the HBV DNA and HCV RNA by molecular biology technique, HBsAg, Anti-HBC, Anti-HCV, Anti-HCMV-IgM, HTLV-1, HTLV-2, HIV-1 and HIV-2 by ELISA and RBC agglutination test were used to detect the TPHA.

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After search at hematopoietic stem cell banks for transplant donors, there may be several donors matched with given standards. To determine the most appropriate donor for a specific patient, the potential donors were analyzed and compared by three methods. The first is cross-reactive group (CREG) antigens, which defined as the public antigens that shared specific serological reaction patterns.

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As one important member of B7/CD28/CTLA-4 costimulatory signal pathway, B7-2 molecule plays a critical role in regulating T-cell response. In order to further explore its effects on regulation of T cell activation, proliferation and associated signal pathways, the cDNA encoding extracellular region of human B7-2 was amplified via PCR and subcloned into some prokaryotic expression vectors to express target protein in host strains. The expressed protein was identified with Western blot and MTT.

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