Objective To construct a prokaryotic expression system for major histocompatibility complex class Ⅰ chain-related gene B ( MICB) and to establish an ELISA method for the detection of anti-MICB antibodies in patients with kidney transplantation. Methods The MICB cDNA fragments were ob-tained by RT-PCR with a pair of specific primers. The MICB cDNA and the prokaryotic expression vector pET-28a were digested by two restriction enzymes and ligated to construct the recombinant expression plas-mid pET-28a-MICB. The transformed E. coli BL21 DE3 strains carrying recombinant expression plasmid were induced by IPTG to express MICB protein. The expressed recombinant proteins were identified by Western blot assay and purified by Ni-NTA Spin column. The purified proteins were coupled to ELISA for the detection of anti-MICB antibodies in patients with kidney transplantation. Results Three common MICB fragments contained the exons 2 and 3 were obtained. The recombinant proteins were expressed in E. coli BL21 DE3 strains carrying pET-28a-MICB and successfully purified by the Ni-NTA Spin column. Results of the Western blot assay confirmed that the obtained proteins were the target proteins. The ELISA method was successfully established and used for the detection of anti-MICB antibodies in 24 patients with kidney trans-plantation. The absorbance values indicated that the sensitivities of three recombinant MICB proteins were different. Conclusion The expression system for MICB gene was successfully constructed. The established ELISA for the detection of anti-MICB antibodies would pave the way for further investigation on the correla-tions between MICB protein and transplantation immunity.

Objective To investigate the effects of methylated CpG islands in the promoter region on the expression of killer cell immunoglobulin-like receptor 3DL1 (KIR3DL1).Methods Three voluntary unpaid blood donors carrying high expression allele KIR 3DL1*01502 and three donors carrying low expres-sion allele KIR3DL1*005 were recruited in this study .The nucleotide sequences and the methylated CpG islands in the promoter regions of KIR 3DL1*01502 allele and KIR3DL1*005 allele were analyzed .The NK cells expressing KIR3DL1*01502 and KIR3DL1*005 were respectively treated with 5-aza for the dem-ethylation of CpG islands within the promoters .The expression of KIR3DL1 protein on the surface of NK cells was measured with flow cytometer .Results Two differences at nucleotide sites -65 and -269 were detected within the promoter regions of KIR3DL1*01502 and KIR3DL1*005, resulting in two distinct CpG islands.The CpG islands within the promoter of KIR 3DL1*01502 allele were highly methylated .The ex-pression of KIR3DL1 protein on NK cells which carried KIR 3DL1*01502 allele was significantly increased after the demethylation of CpG islands .However , the treatment of demethylation had no significant effects on the expression KIR3DL1 protein on NK cells harboring KIR3DL1*005 allele.Conclusion The methylated CpG islands within the promoter of KIR 3DL1*01502 allele affected the antigen expression on the surface of NK cells.Different KIR3DL1 alleles might show different mechanisms in regulating antigen expression .

OBJECTIVETo establish a polymerase chain reaction sequencing-based typing (PCR SBT) method for HLA-DPB1 exons 2 and 3, and to analyze their polymorphisms.

METHODSBased on the sequences of HLA-DPB1 loci, locus-specific primers were designed and applied to amplify the target sequences encompassing the entire exons 2 and 3 of HLA-DPB1. The amplification products were digested by enzymes and directly sequenced in both directions. The genotype was assigned by Assign 3.5+ SBT software.

RESULTSSpecific target fragment was obtained with the PCR amplification, and good quality electropherogram was derived by direct sequencing. Among 242 individuals from Zhejiang Han population, 18 HLA-DPB1 alleles were detected. Alleles with a frequency of > 0.05 have included DPB1*05:01:01/135:01 (0.4112), DPB1*02:01:02 (0.1901), DPB1*04:01:01 (0.1136) and DPB1*02:02 (0.0620). A novel HLA-DPB1*168:01 allele has also been identified. Nine polymorphism sites were founded in the exon 3 region, which included a new SNP site 517 A>T.

CONCLUSIONThe PCR-SBT method for exons 2 and 3 of HLA-DPB1 is reliable, which allowed detection of polymorphisms in exon 3 of the HLA-DPB1 gene.

Alleles ; Exons ; HLA-DP beta-Chains ; genetics ; Humans ; Polymerase Chain Reaction ; Polymorphism, Genetic

OBJECTIVETo explore the function of a novel nonsense mutation c.1476G>A of ITGB3 gene using an in vitro expression system.

METHODSAn eukaryotic expression vector containing ITGB3 c.1476G>A cDNA was generated by site-directed mutagenesis and transformed into E.coli. Plasmid DNA was extracted and sequenced to confirm the target mutations. Wild-type and mutant recombination plasmids were transfected into Chinese hamster ovarian cancer (CHO) cells by nonliposome method, and the stable expression cells were harvested by G418 screening. The ITGB3 gene mRNA transcription and GPIIIa expression level in CHO cells were detected with real-time quantitative PCR, Western blotting and flow cytometry, respectively.

RESULTSThe eukaryotic expression vectors of wild ITGB3 cDNA and c.1476G>A mutant were successfully constructed. CHO cells with stable expression were obtained after transfection and screening. Compared with the wild-type transfected cells, the amount of CD61 antigen expression was 37% and mRNA transcription level was only 6% in the mutant-transfected cells. Full length GPIIIa protein was found only in the stably wild-type-transfected cells, but not in mutant-transfected cells by Western blotting analysis.

CONCLUSIONThe ITGB3 c.1476G>A mutation can decrease the transcription level and further affect GPIIIa synthesis and CD61 antigen expression.

Animals ; Base Sequence ; Blood Platelets ; cytology ; metabolism ; CHO Cells ; Cloning, Molecular ; Codon, Nonsense ; genetics ; Cricetinae ; Cricetulus ; Humans ; Integrin beta3 ; genetics ; metabolism ; Molecular Sequence Data ; Plasmids ; genetics ; metabolism ; Point Mutation

OBJECTIVETo study the serological characteristics and molecular mechanism for a rare Pk phenotype of the P1Pk blood group system.

METHODSThe blood group of the proband was identified by serological techniques. The coding region and flanking intronic sequences of the β-1,3-N-acetylgalactosyltransferase gene (B3GALANT1) associated with the Pk phenotype were analyzed using polymerase chain reaction sequence-based typing.

RESULTSThe proband was identified as having a rare Pk phenotype including anti-P in her serum. The blood group of her daughter and husband showed a P2 phenotype. The nucleotide sequences of the B3GALANT1 gene of her husband and two randomly-chosen individuals were the same as the reference sequence (GenBank AB050855). Nucleotide position 433 C>T homozygous mutation in the B3GALANT1 was found in the proband, which has resulted in a stop codon at amino acid position 145, which may produce a premature protein capable of decreasing or inhibiting the activity of the β -1,3-N-acetylgalactosyltransferase. The nucleotide position 433 C/T heterozygous in the B3GALANT1 was found in her daughter.

CONCLUSIONThe Pk phenotype resulted from 433 C>T mutation in the B3GALANT1 gene has been identified.

ABO Blood-Group System ; genetics ; Adult ; Base Sequence ; Blood Grouping and Crossmatching ; Female ; Genotype ; Humans ; Male ; Molecular Sequence Data ; N-Acetylgalactosaminyltransferases ; genetics ; Pedigree ; Phenotype ; Point Mutation

OBJECTIVETo explore the molecular basis for an individual with rare p phenotype in the P1Pk blood group system.

METHODSErythrocyte blood group antigens and antibodies in serum were identified in the proband and five family members with a serological method. Coding regions and flanking untranslated regions of the α1,4-galactosyltransferase gene (A4GALT) encoding P1Pk antigens were amplified with polymerase chain reaction and directly sequenced. The haplotypes of A4GALT in the parents of the proband were also analyzed by cloning sequencing.

RESULTSThe proband was found with a rare p phenotype with anti-Tja antibody in his serum by serological method. The other family members all had a common P2 phenotype. The results of DNA sequencing showed that a cytosine was inserted at nucleotide position 1026 to 1029 (1026_1029insC) of both alleles of the A4GALT gene in the proband. The mutation has caused a reading frame shift and formed a mutant protein by extending 92 amino acid residues. The other family members were either heterozygous for the insertion or of the wild type at above position.

CONCLUSIONThe 1026_1029insC mutation of the A4GALT gene is probably responsible for the p phenotype identified for the first time in Chinese population. The individual with the p phenotype possesses anti-Tja antibody.

ABO Blood-Group System ; genetics ; Adult ; Alleles ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Female ; Frameshift Mutation ; Galactosyltransferases ; genetics ; Humans ; Male ; Molecular Sequence Data ; Mutagenesis, Insertional ; Pedigree ; Phenotype ; Young Adult

OBJECTIVETo explore the effect of α -1,2 fucosyltransferase (FUT1) gene 682A> G and 547_552delAG mutations on the expression of FUT1 mRNA and activity of α -1,2 fucosyltransferase.

METHODSRecombinant expression vectors of FUT1 682A> G and FUT1 547_552delAG were constructed and transfected into COS-7 cells for stable expression screening. Expression of FUT1 mRNA was determined using real-time quantitative PCR. The activity of FUT1 was measured with high-performance liquid chromatography.

RESULTSStably transfected COS-7 cells with wild type FUT1, FUT1 682A> G and FUT1 547_552delAG were respectively obtained. The FUT1 mRNA level of transfected cells with 682A> G and 547_552delAG recombination vectors have measured 101.69% and 102.79% compared with that of wild type FUT1 transfected cells. A specific protein band with about 46 kD was confirmed in the 682A> G transfected cell lysates by SDS-PAGE electrophoresis and Western blotting with 6× His Tag antibody. Similar protein was not identified in the 547_552delAG cells lysates. Enzymes activity of FUT1 682A> G has measured 61.01% compared with wild type FUT1 protein, whilst the activity of FUT1 547_557delAG was completely abolished.

CONCLUSIONFUT1 682A> G and 547_552delAG mutations do not affect the transcript efficiency, although various mutations have different impact on the enzyme's activity.

Animals ; Base Sequence ; Blotting, Western ; COS Cells ; Cercopithecus aethiops ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Fucosyltransferases ; genetics ; metabolism ; Humans ; Mutation ; Recombinant Proteins ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo analyze specific expression of blood group genes using nucleated erythroid cells cultured from un-mobilized peripheral stem cells in vitro.

METHODSHematopoietic stem cells(HSC) bearing the CD34 antigen were isolated from peripheral blood by centrifugation and magnetic beads sorting, followed by suspension culture in vitro. Cells were collected from medium on various stages and analyzed by immunofluorescence. The RNA transcription of RH and ABO blood group genes was analyzed using culture cells on day 12.

RESULTSA total of(3.19±0.13) ×10 (4) CD34+cells were isolated from about 50 mL peripheral blood with a recovery rate of 67.3%±2.7%. The cells amount in erythroid-lineage culture system on day 9 reached a plateau of a 237.1±15.5-fold amplification of the initial cell input. The stem cell-specific CD34 antigen was dropped off, while the erythroid-specific CD235a and CD240D antigens were increased in culture period. RHD/CE and ABO genes can be amplified using RNA extracted from culture cells on day 12, and genotypes of Rh and ABO systems by DNA sequencing were consistent with their serologic phenotypes.

CONCLUSIONA method was established to analyze the gene expression of erythroid blood group derived from un-mobilized peripheral stem cells cultured in vitro. It can be used to study the expression of various erythroid-specific genes.

Antigens, CD34 ; analysis ; genetics ; Base Sequence ; Blood Group Antigens ; analysis ; genetics ; Cells, Cultured ; Erythrocytes ; cytology ; Flow Cytometry ; Hematopoietic Stem Cells ; cytology ; Humans ; Molecular Sequence Data

OBJECTIVETo develop a method for separating the human leukocyte antigen (HLA)-A, -B and -C haploid using biotinylated probes and streptavidin magnetic beads in order to solve ambiguous HLA genotyping results.

METHODSBased on sequence information of HLA alleles from the IMGT/HLA database, the 5-biotinylated probes were designed. The probe was mixed and extended with corresponding genomic DNA, and incubated with streptavidin magnetic beads, which could form a streptavidin magnetic beads-biotin-probe DNA complex. The unique DNA haploid binding to corresponding probe was isolated after washes and elution. The separated haploid genomic DNA was used as template for HLA-A, -B and -C loci amplification and sequencing analysis.

RESULTSAmong the 12 HLA-A probes, 19 HLA-B probes and 13 HLA-C probes, DNA sequencing has confirmed that 9 HLA-A probes, 9 HLA-B probes and 5 HLA-C probes could successfully separate the haploid from genomic DNA samples.

CONCLUSIONThe developed method for HLA-A, -B and -C haploid separation is reliable, which can solve certain ambiguity and improve the accuracy of HLA genotyping.

Genotype ; HLA-A Antigens ; genetics ; HLA-B Antigens ; genetics ; HLA-C Antigens ; genetics ; Haploidy ; Humans ; Molecular Probe Techniques ; instrumentation ; Polymerase Chain Reaction ; instrumentation ; methods ; Streptavidin ; chemistry