[Identification and the Related Molecular Mechanism of B(A)04 Allele].

OBJECTIVE: To investigate the identification and molecular biological mechanism of a case of B(A)04 allele. METHODS: The ABO blood groups of the proband and his nine family members were analyzed serologically and DNA sequencing was used to accurately determine the genotypes of these ten specimens. The cartoon models of local active center of enzymes of the GTA,GTB and the GTB mutant were constructed to explore the possible molecular mechanism leading to abnormal enzyme-catalyzed A antigen synthesis. RESULTS: The serological results suggested that the ABO blood groups of the proband, his elder brother and his maternal grandmother were AweakB or B(A); the ABO blood group of his mother was type AB, his uncle and elder aunt were type B, and his father was type O. ABO blood group gene sequencing results showed that 6 out of 10 members of the family carried the B(A)04 allele. Molecular structure models suggested that the spatial distance of critical amino acid residues in the catalytic center of the GTB mutant enzyme was greater than that of GTB, which might cause the enzyme to abnormally catalyze the synthesis of A antigen. CONCLUSION: The characteristics of serological reactions of B(A) blood subgroup are complicated, and its identification needs to be combined with molecular biology and pedigree investigation. It is speculated that the B(A) phenotype may be associated with a larger volume of the catalytic center in the GTB mutant.

[Serological Characteristics and Molecular Biological Mechanism of AEL.02 Subtype].

OBJECTIVE: To explore the serological characteristics and molecular biological mechanism of an ael subtype specimen. METHODS: The ABO blood typing was identified by routine blood group serological and absorption/elution methods; PCR-SBT method for ABO genotyping: 7 exons of ABO gene were amplified by PCR, the amplified products were purified, and then sequencing primers were designed and the amplified products were sequenced directly for analysis; 3D molecular model was constructed and the difference of free energy (ΔΔG) was used to predict the GTA mutant stability. RESULTS: A antigen was not detected on erythrocytes through absorption and elution tests, which was not consistent with the serological characteristics of ael, and the serological typing results were ambiguous. The ABO genotype was ABO*AEL.02/O.01.01, and there were two mutations in exon 7 of the gene, c.467C>T and c.646T>A, which could lead to the replacement of proline with leucine at position 156 (p.Pro156Leu) and phenylalanine with isoleucine at position 216 on the GTA, respectively. The 3D model predicts that the mutations do not introduce new hydrogen bonds to the GTA mutant and do not form a new secondary structure, but can lead to an increase in the ΔΔG value of the GTA mutant, suggesting a decrease in protein stability. CONCLUSION: The serological characteristics alone is not reliable to determine the ael subype; the ael phenotype may be due to the GTA mutant that reduces enzyme stability.

Association of HLA alleles (A, B, DRB1) and HIV-1 infection in the Han population of Hubei, China.

The HIV susceptibility and resistance alleles in the HLA genes were determined by investigating the distribution characteristics of the HLA alleles (A, B, and DRB1) in HIV-infected individuals of the Han population in Hubei, and by comparing these alleles with HIV-negative individuals from the same area. A cohort of 424 HIV-1 infected individuals were chosen as study subjects, and 836 HIV-negative healthy subjects from the same area served as the control population. HLA-A, B, and DRB1 allele typing was performed using polymerase chain reaction-sequence-specific oligonucleotide probes (PCR-SSOP) and polymerase chain reaction-sequencing based typing (PCR-SBT) techniques. Arlequin ver3.0 was used to analyze the allele and haplotype frequencies of HLA-A, B, and DRB 1, whereas Epi Info 7 and SPSS18.0 was used to analyze the differences in the HLA alleles between the HIV-1 positive and HIV-1 negative groups. A*02:03, DRB1*01:01, and DRB1*15:01 alleles and their haplotypes as well as the HLA_Bw4-Bw6 hybrid showed a protective effect on HIV-1 infection. After adjusting for confounding factors such as age and sex, multivariate logistic regression analysis revealed that B*15:02G, DRB1*01:01, and DRB1*15:01 subtypes were the resistance genes of HIV-1 infection, while B*13:01 might increase susceptibility to HIV-1 infection. The correlation between A*02:06 and B*15:01G subtypes and HIV-1 susceptibility was independent of the age and sex of the host. This study demonstrated the influence of genetic factors in humans such as HLA polymorphism on individuals to resist HIV-1 infection. Association studies of HLA polymorphism, susceptibility/resistance to HIV-1 infection, and hosts' genetic background are of significant importance for research on HIV-1 pathogenesis and vaccine design.

Association of HLA Alleles (A, B, DRB1) and HIV-1 Infection in the Han Population of Hubei, China / 华中科技大学学报（医学）（英德文版）

The HIV susceptibility and resistance alleles in the HLA genes were determined by investigating the distribution characteristics of the HLA alleles (A,B,and DRB1) in HIV-infected individuals of the Han population in Hubei,and by comparing these alleles with HIV-negative individuals from the same area.A cohort of 424 HIV-1 infected individuals were chosen as study subjects,and 836 HIV-negative healthy subjects from the same area served as the control population.HLA-A,B,and DRB 1 allele typing was performed using polymemse chain reaction-sequence-specific oligonucleotide probes (PCR-SSOP) and polymerase chain reaction-sequencing based typing (PCR-SBT) techniques.Arlequin ver3.0 was used to analyze the allele and haplotype frequencies of HLA-A,B,and DRB l,whereas Epi Info 7 and SPSS18.0 was used to analyze the differences in the HLA alleles between the HIV-1 positive and HIV-1 negative groups.A*02:03,DRB1*01:01,and DRB1*15:01 alleles and their haplotypes as well as the HLA_Bw4-Bw6 hybrid showed a protective effect on HIV-1 infection.After adjusting for confounding factors such as age and sex,multivariate logistic regression analysis revealed that B* 15:02G,DRB 1*01:01,and DRB 1 * 15:01 subtypes were the resistance genes of HIV-1 infection,while B * 13:01 might increase susceptibility to HIV-1 infection.The correlation between A*02:06 and B*15:01G subtypes and HIV-1 susceptibility was independent of the age and sex of the host.This study demonstrated the influence of genetic factors in humans such as HLA polymorphism on individuals to resist HIV-1 infection.Association studies of HLA polymorphism,susceptibility/resistance to HIV-1 infection,and hosts' genetic background are of significant importance for research on HIV-1 pathogenesis and vaccine design.