HLA新等位基因A*3018的序列分析和确认

为了识别和确认中国汉族人群中的HLA新等位基因,使用PCR-SSP、FLOW-SSO以及PCR-SBT等HLA分型技术,发现样本A位点的杂合结果A*240201,300101在外显子2有3个位置与数据库不相符。用组特异性引物分别扩增A*24及A*30基因,对外显子2、3、4进行双向测序,发现1个与A*300101序列相近的新等位基因。分析该等位基因与A*300101序列的差异。用EB病毒感染外周血B淋巴细胞,建立该等位基因的无限增殖化B淋巴细胞系。结果表明:该基因与A*300101相比在外显子2有3个碱基的改变,碱基121A→C、123T→C导致密码子17AGT->CGC,17S(丝氨酸)→R(精氨酸);碱基126A→G导致密码子18GGA→GGG,18G(甘氨酸)→G(甘氨酸),该氨基酸是同义突变。成功建立了该等位基因的无限增殖化B淋巴细胞系,该基因序列已提交GenBank,编号为DQ872509。结论:该等位基因为新的HLA-A等位基因,已于2006年8月被世界卫生组织HLA因子命名委员会正式命名为HLA-A*3018(上报编号HWS10004039)。

Identification and Sequence Analysis of A Novel HLA.A*3018 Allele

To identify HLA novel allele in Chinese Han individuals, an unknown HLA-A allele was detected by PCR-SSP and FLOW-SSO in Chinese Han individuals. Heterozygous sequence-based typing (SBT) showed that there were 3 differences compared with database in exon 2. Its anomalous patterns suggested the possible presence of either a novel A * 30 or a novel A * 24. To separate the two alleles and to determine whether the allele is novel, the HLA-A * 30 and HLA-A * 24 alleles were amplified separately by using a commercial kit for the single allele-specific sequencing strategy, and both alleles for exons 2 - 4 were sequenced according to the manufacturer' protocol. To prepare B-lymphoblastoid cell line of the novel HLA allele by using Epstein-Barr virus-infected B-lymphoblastoid cells in the peripheral blood. The results indicated that the sequencing results showed HLA-A alleles of the sample to be HLA-A * 240201 and a new A * 30 allele. The sequences of the new A*30 were identical to those of HLA-A * 300101 except for three nucleotide changes in exon 2: at nt 121 (A-->C), nt 123 (T-->C) and nt 126 (A-->G), resulting in an amino acid residue substitution from S (AGT) to R (CGC) at codon 17 and a synonymous substitution from G (GGA) to G (GGG) at codon 18. Immortalized B-lymphoblastoid cell line of the novel HLA-A * 3018 allele was achieved, the sequence of HLA-A * 3018 allele was submitted to GenBank and its accession number was DQ872509. In conclusion, the HLA-A * 3018 is a novel HLA-A allele and has been officially named HLA-A * 3018 by the WHO Nomenclature committee in August 2006 (HWS10004039).