PCR-SSP法HLA-A、B基因分型与血清学分型的比较

目的比较聚合酶链反应-序列特异性引物(PCR-SSP)进行HLA-Ⅰ类A、B抗原位点分型的准确性,并探讨血清学分型错误发生的原因。方法用PCR-SSP以及单克隆抗体血清学分型技术对HLA-A、B分型并比较。结果34例样本PCR-SSP基因分型无假阳性和假阴性出现。PCR-SSP法与血清学比较,血清学检出错误或漏检率分别为HLA-A位点23.5%,B位点26.5%。血清学发生错误或易混淆的抗原有:A2和A68、A32和A33,B5、B60和61。结论PCR-SSP法进行HLA-A、B抗原等位基因分型具有分辨率高、特异性强、重复性好、实验过程简捷快速、分型结果较血清学更加准确可靠的优点。     

HLA-DR 52- and 51-associated DRB1 alleles in Kenya, East Africa

The genes of the major histocompatibility complex (MHC) are amongst the most polymorphic loci known in the human population. The population genetics of the MHC encoded HLA loci of sub-Saharan Africa are of major interest because of their particular genetic diversity. Here we report on the HLA-DR 52- and 51-associated determinants of the DRB1 loci observed in 165 East African individuals studied in Nairobi, Kenya. The HLA-DR typing was done by serologic and by molecular DNA techniques (PCR-SSOP). The most frequent allele identified was DRB1*1101, followed by DRB1*1503 and DRB1*1302. Some unexpected alleles were repeatedly identified: DRB1*1108, DRB1*1316 and DRB1*1421. Most oftheDR 52-and 51-associated DRB1 alleles were correctly identified by serology as part of the DR3, DR5, DR6 and DR2 groups respectively. The HLA-DRB1 profile reported here corroborates previous genetic and linguistic data supporting the concept that the Eastern African Black population is genetically distinct from other African Black populations. This has important implications in public health issues related to the genetic profile of a population (transplantation, vaccine design for example).     

Lack of Allelic Preference in Amplification and Loss of the c-myc Oncogene in Methylcholanthrene-induced Mouse Sarcomas

Sarcomas were induced in Fl mice between C57BL/6N and C3H/He strains by subcutaneous injection of methylcholanthrene. The c-myc oncogene was found to be amplified in 16 cases among 43 sarcomas of C57BL/6N × C3H/He mice and 1 case among 5 sarcomas of the reciprocal cross. The origin of the amplified allele was determined by the polymerase chain reaction single strand conformation polymorphism analysis. Among the 17 sarcomas, only one had both of the alleles amplified. The rest of the tumors carried the amplified c-myc allele coming either from C57BL/6N (9 cases) or from C3H/He (8 cases). These results indicate that the c-myc allele is amplified randomly in methylcholanthrene-induced mouse sarcomas irrespective of its origin, such as paternal or maternal allele and C57BL/6N or C3H/He allele. In addition to these changes, the unamplified c-myc oncogene was found to be lost in 12 cases out of the 17 sarcomas with the amplification.     

Elongation of the cytoplasmic domain,due to a point deletion at exon 7, results in an HLA-C null allele,Cw*0409 N

The development of molecular techniques for HLA typing has allowed the identification of genes previously assigned as serologic blank alleles. Lack or poor cell surface expression has been found for molecules coded by HLA-A, -B, -DRB4, -DRB5, and -DPB1 genes. In this report we describe the first HLA-C gene encoding for a null cell surface molecule. HLA-Cw*0409 N shows a point deletion at position 1095 within exon 7. This mutation provokes a codon reading shift, generating a new translation stop codon 97 bp downstream to that described in alleles normally expressed. This new stop codon location implies the presence of 32 extra amino acid residues in the cytoplasmic domain. Transfection experiments suggest that elongation of the cytoplasmic domain in Cw*0409 N would be the cause of cell surface expression failure, although Cw*0409 N heavy chain is able to create stable complexes with beta2-microglobulin. HLA-C fragment length analysis in a small selected group of samples with B44-Cblk haplotypic associations allowed us to identify two additional subjects showing both a serologic silent Cw*04 allele and a point base deletion at the 3' end of the HLA-C gene. This finding indicates that the allele frequency of Cw*0409 N within serologic C blank alleles would be appreciable, although basically restricted to the (A23)-Cw*0409 N-B*4403-DR7-DQ2 haplotype.     

华北地区汉族群体15个短串联重复序列基因座遗传多态性分析

目的调查华北地区汉族人群15个短串联重复序列(shorttandemrepeat,STR)基因座遗传多态性分布和群体遗传学数据。方法应用毛细管电泳技术和五色荧光复合扩增的方法,检测597名汉族无关个体的15个STR基因座基因型。结果15个STR基因座的基因频率分布均符合Hardy-Weinberg平衡,所检测的15个STR遗传标记均具有高度多态性,杂合度均超过0.62,15个基因座的个体识别力在0.802~0.967之间,非父排除率在0.320~0·697之间,匹配概率在0.033~0.198之间。15个基因座的累积个体识别能力为0.999999以上,累积非父排除率为0.99999571,累积匹配概率为8.93×10-18。结论联合检测15个基因座可为亲缘鉴定和个体识别提供可靠的法医学证据,这15个STR基因座适用于中国人群的法医物证学检验。     

Strong association between HLA-Cw*0706 and HLA-B*44032 in the Bubi population from Equatorial Guinea

Unrelated Bubi, native to the island of Bioko (Equatorial Guinea), were previously typed by low-resolution polymerase chain reaction using sequence-specific primers (PCR-SSP) and serology for HLA-A, -B and -C. HLA-B*44 was found frequently and associated with Cw*07. We have studied the HLA subtypes of 20 B*44pos/Cw*07pos Bubi individuals. HLA-B and -C were typed by sequencing exons 2 and 3. To distinguish the alleles Cw*1701/02/03, Cw*07011/012/06 and Cw*1801/02 additional sequencing of exon 1 or 5 was performed. All 20 B*44pos/Cw*07pos individuals of the Bubi population were typed Cw*0706 positive. Nineteen of them carried the B*44032 allele and one B*4407. In addition, 19 B*44neg/ Cw*07pos Bubi individuals were typed for HLA-C and none of them proved Cw*0706 positive. To determine whether the association between Cw*0706 and B*44032 was limited to the Bubi, 19 individuals from Dutch Caucasian families were typed in which B44 and Cw7 segregated on one haplotype. None of these individuals showed the presence of B*44032 or Cw*0706. The haplotypes found in the Dutch Caucasians were B*4402-Cw*0704, B*44031-Cw*07011 and B*44031-Cw*0702. The present observation indicates a strong association between B*44032 and Cw*0706 in the Bubi population.     

Increased frequency of the rare PstI allele (P2) in a population of CAD patients in Northern Greece

Restriction fragment length polymorphisms (RFLPs) at the apolipoprotein AI-CIII-AIV gene cluster and their association with coronary artery disease (CAD) and lipid levels were studied in a Northern Greek population. Ninety-five patients with CAD and fifty-four normal controls, angio-graphically proven, were included in this study. Using genomic hybridization techniques, three polymorphic restriction sites were identified at this locus: the PstI at the 3' end of the apoAI gene, the SacI at the 3' non-coding region of the apoCIII gene and the PvuII at the intergenic region between the apoCIII-AIV genes. The rare allele (P2) arising from the absence of the PstI restriction site was observed with a significantly higher frequency (p<0.01) in patients compared to normals (0.11 vs 0.02). In contrast, the rare allele for the SacI polymorphic site had a similar distribution among patients and controls (0.12 vs 0.16). The same was observed for the PvuII RFLP (0.04 vs 0.05). Correlation of lipid and apolipoprotein AI levels with the three RFLPs revealed no significant association, although apo AI and HDL were lower in patients with the P2 allele. Thus, in this Greek population, only the PstI polymorphism, among the polymorphic restriction sites examined, appears to be associated with CAD.     

Polymorphism of the ABO blood group genes in Han, Kazak and Uygur populations in the Silk Route of northwestern China

Genetic polymorphism in the ABO blood group gene of Han, Kazak and Uygur populations inhabiting the most northwestern part of China was investigated using polymerase chain reaction-based techniques. The present study enrolled 43 healthy unrelated Han, 37 Kazak and 59 Uygur volunteers. The allele in A1 blood group is distinguished A0101 and A0102 in difference of nucleotide position 467. The A0101 allele is more frequent in Caucasian and the A0102 allele is characteristic in Mongoloid. It must be notable that A0201 in the A2 group (with a single base deletion at nucleotides 1059 to 1061) which was characteristic of Caucasian was observed in Kazak and Uygur populations but not in Han. Further, 00201 (with no nucleotide deletion at 261 and three nucleotide differences), which is frequent in different races including Caucasian except for Mongoloid, was detected also in Kazak and Uygur populations. The frequencies of B0101 in Kazak, Uygur and Han were comparable to those of other Asian populations but higher than those of Caucasian populations. Collectively, these results reveal that the allele frequencies of Kazak and Uygur at the ABO blood group locus are an intermediate between those of Mongoloid and Caucasian, suggesting the admixed feature of Kazak and Uygur with Mongoloid and Caucasian.     

新等位基因人类白细胞抗原B*4609的发现和确认

目的 鉴定一个人类白细胞抗原(human leukocyte antigen,HLA)新等位基因HLA-B*4609.方法 使用序列特异性寡核苷酸PCR技术进行HLA基因分型,发现反应格局异常的可疑新等位基因,应用分子克隆和DNA双向测序技术测定新等位基因的核苷酸序列,并与已知等位基因进行序列比对分析.结果 检出1个样本HLA-B位点反应格局异常,DNA测序分型结果一个为B*151101,另一个的核苷酸序列与已知的HLA等位基因均不同,该基因序列与同源性最高的HLA-B*460101基因序列相比,在第3外显子区域中527位碱基发生A→T突变,导致176位编码氨基酸由谷氨酸(GAG)变成缬氨酸(GTG).结论 样本中含有HLA-B新等位基因序列.该序列申报后,被世界卫生组织HLA因子命名委员会正式命名为HLA-B*4609.