HLA-B Allelic Polymorphism Analysis And Its Application In Sichuan Yi, Xinjiang Uygur Populations

HLA is the most polymorphic gene complex of all human genetic systems, play a key role in specific immune response, determine the heterogeneity of individual associated with disease. Analyzing the distribution of its polymorphism has been used in fields of forensic medicine, anthropology and disease association. There is no report about the DNA polymorphism of HLA-B gene in Sichuan Yi ethnic group and Xinjiang Uygur ethnic group, and the morbidity of HIV infection is high in Sichuan Yi ethnic group and Xinjiang Uygur ethnic group, which would be the candidate area of HIV vaccine's clinical experiment in the future.So, in this study, we investigated and analyzed HLA-B DNA polymorphism in the two ethnic groups, the results would provide population genetic data for forensic implication and origin tracing of Yi ethnic group and Uygur ethnic group. The study on the association of HLA-B allele with HIV infection would be acting as basic work for further study on pathogenesis of HIV infection and the evaluation of HIV vaccine, also it would supply the basic data to contruct mathematic model of HIV transmission in ChinaIn our work, PCR-SSP and SBT gene typing method of HLA-B were first established. Next, HLA-B typing was carried out by PCR-SSP and SBT, in unrelated healthy control subjects and HIV-1 infected subjects of Sichuan Yi ethnic group and Xinjiang Uygur ethnic group. The HLA-B allele frequencies of healthy subjects in Yis and Uygurs were used to study on processing forensic casework and tracing the origins of two ethnic groups. To investigate the HLA-B allele association with HIV-1 infection, the allele frequencies of healthy subjects and HIV-1 infection subjects were analyze. A long term non-progressor of HIV-1 infection was done HLA typing and analyzed its HLA restricted CTL epitopes to study the influence of HLA on disease progression after HIV-1 infection.The method of HLA-B typing by PCR-SSP consisted of 42 typing reactions to each sample by combining 52 allele specific primers and one pair of internal controlprimers. SBT is based on a single PCR amplification of gene fragment spanning the 2nd exon, 2nd intron and 3rd exon of the HLA-B locus. The amplification product is used as cycle sequencing template. The sequencing reaction is performed with nested primers matching conserved sequence in 1st, 2nd, and 3rd introns. The typing result of SBT was obtained from the sequence of 2nd exon and 3rd exon alignment with HLA database. It is more accurate and quick for HLA-B DNA typing combining two methods together.Twenty alleles (or allele-groups) were detected in HLA-B loci in 106 Sichuan unrelated Yi healthy subjects. Of them, B*40, B*15 and B*51 were the most common alleles with an allele frequency of 0.2208, 0.1604, 0.1274 respectively; B*47, B*27, B*44, B*18 and B*78 were the rare alleles with an allele frequency of 0.0189, 0.0142, 0.0142, 0.0094 and 0.0047 respectively. Meanwhile, 27 alleles (or allele-groups) were detected in HLA-B loci in 110 Xinjiang unrelated healthy Uygur subjects. Of them, B*35 and B*51 were the most common alleles with an allele frequency of 0.1136 and 0.1136 respectively; B*41, B*56 and B*78 were the rare alleles with a frequency of 0.0045, 0.0045 and 0.0091 respectively. 5^ tests showed that HLA-B loci of the two ethnic groups both accorded with Hardy-Weinberg equilibrium. Heterozygosity (H), discrimination power (DP) and probability of paternity exclusion (EP) of HLA-B locus from Sichuan Yi ethnic group were computed to be 0.8977, 0.9661 and 0.8009; and those from Xinjiang Uygur ethnic group as 0.9372, 0.9857 and 0.8732. The results suggest that HLA-B locus was a high resolution genetic marker of two ethnic groups in this study. It has useful application in forensic personal identification and paternity test.Comparing with the main world wide ethnic group, the "Asia Mongoloid origin" HLA alleles such as B*46 and B*5401were both detected in Sichuan Yis and Xinjiang Uygurs; The distribution of HLA-B allele frequencies in Sichuan Yis was between Southern Han and Northern Han; F...