Novel HLA-A*11 allele, A*1120, identified by sequence-based typing

In this report, we describe the identification of a human leucocyte antigen-A*11 (HLA-A*11) nucleotide sequence variant, a new HLA-A*1120 by using sequence-based typing (SBT). The new allele was detected during routine HLA typing by high-resolution SBT. Allele A*1120 showed one nucleotide difference with A*110101 at codon 152 (GCG-->GAG) resulting in an amino acid change from alanine to glutamate. Residue 152 is located on alpha(2)-helix of HLA class I molecule and involved in peptide binding by constructing E pocket of peptide-binding groove, implying that the change of the residue 152 would affect the binding affinity of peptides to A*1120 allele.     

HLA-A*0203-BSP的表达和复性及其四聚体的鉴定

目的：优化诱导条件大批量表达生物素化酶BirA底物肽（BSP）与HLA-A＊0203重链胞外域的融合蛋白（HLA—A＊0203、BSP），并制备负载HLA-A＊0203限制性EB病毒抗原肽EBNA3 596-604的四聚体（HIA—A}0203／SVR）。方法：以HLA—A＊0203-BSP原核表达载体转化E．coli BL21（DE3）菌株，优化诱导条件进行大批量重组蛋白的表达。通过稀释法复性可溶性HLA-A＊0203／SVR单体，然后以BirA对其进行生物素化，并以阴离子交换树脂纯化。将纯化的HLA-A＊0203／SVR单体与荧光素标记的链亲和素按4：1的比例混合形成四聚体，通过对特异性CTL进行染色验证其结合活性。结果：当IPTG的浓度为0．4mmol／L，于37℃诱导过夜后，融合蛋白的表达最多。该重组蛋白相对分子质量（Mr）为34003，与HLA—A＊0203-BSP的理论Mr相一致。该重组蛋白以包涵体形式存在于沉淀部分，约占菌体总蛋白的30％。负载抗原肽的可溶性HLA-A＊0203／SVR单体是在同时存在HLA-A＊0203，BSP、β2微球蛋白及HLA-A＊0203限制性抗原肽SVR的情况下通过稀释法复性而获得。该单体生物素化并纯化后与荧光素标记的链亲和素按4：1的比例混合后即形成四聚体。流式细胞术（FCM）分析证实，该四聚体具有与HLA—A2^＋供者特异性CTL结合的活性。结论：HLA—A＊0203-BSP融合蛋白在优化条件下获得高效表达。以此蛋白制备的HLA-A＊0203／SVR四聚体具有与HLA-A2^＋供者特异性CTL结合的活性，为研究HLA—A＊0203个体EB病毒特异性CTL的免疫应答打下了基础。     

Identification of three new DRB3* (DRB3*0106, DRB3*0107 and DRB3*02022) alleles

Three novel DRB3* alleles were identified using CANTYPE reverse hybridization assay. The initial unusual hybridization patterns of DRB3-specific polymerase chain reaction (PCR)-amplified DNA from each subject were confirmed by cloning and sequencing analysis. DRB3*0106 allele is identical to DRB3*0101 except for a single nucleotide substitution (CTG-->GTG) changing codon 38 from Leu to Val. This polymorphism is commonly found in DRB3*03 alleles. Compared with DRB3*0202, DRB3*02022 contains a single silent nucleotide substitution (AAT-->AAC, both encoding for Asn) at codon 77. This polymorphism is also present in DRB3*0204 allele. The new DRB3*0107 allele has a sequence unique to DRB3 alleles. From codon 5 to codon 36 the sequence is identical to that of DRB3*0101 allele. From codon 37 to codon 87 the sequence of DRB1*0107 allele is identical to that of DRB3*0202. This sequence would thus explain the CANTYPE(R) DRB3-specific unusual pattern of reactions. The new DRB3*0107 could have arisen from a gene conversion between DRB3*0101 and DRB3*0202 alleles, but the DRB3*0106 and the DRB3*02022 may have been generated by a point mutation event. The DRB3*0107 allele was identified in a Caucasoid individual. The ethnic origin of the subjects carrying the other two alleles are unknown. The three alleles presented here were only identified once, in a total population of 49,000.     

Possible susceptibility of the HLA-DPB1*0402 and HLA-DPB1*04 alleles to unexplained recurrent abortion: analysis by means of polymerase chain reaction-restricted fragment length polymorphism method

PROBLEM: To clarify whether HLA-DP antigens are associated with patient population of unexplained recurrent abortion. METHOD OF STUDY: The frequency of HLA-DPB1 alleles in patients with unexplained recurrent abortion, and the compatibility of HLA-DPB1 alleles between patient couples, were studied using a polymerase chain reaction (PCR)-restricted fragment length polymorphism (RFLP) method. Thirty patients who had a history of unexplained primary recurrent abortion, and their husbands, were typed for HLA-DPB1 genotype. Two hundred and ninety-nine base pair fragments from the second exon of HLA-DPB1 genes were selectively amplified using the PCR-primers. After amplification, the DNAs were digested with restriction endonucleases, and subjected to electrophoresis in a 12% polyacrilamide gel to determine HLA-DPB1 genotype. RESULTS: The frequency of HLA-DPB1*0402 and DPB1*04 alleles in the patient group (n = 30) was significantly increased, as compared to that in the normal fertile women (n = 30). The frequency of HLA-DPB1*04 allele in the patient group was significantly increased, as compared to that in the general population (n = 112). No significant compatibility of HLA-DPB1 alleles could be observed between patient couples and normal fertile couples. CONCLUSION: These findings suggest a possible new class II association with patient population of unexplained recurrent abortion.     

Identification of novel DRBI*13 (DRB1*1333), DRB1*04(DRB1*0426) and DRB5* (DRB5*0109) alleles

Abstract: Three novel HLA class H alleles (DRB1*1333, DRB1*O426, DRB5*0109) are described here. The 3 novel alleles were initially detected as previously unidentified SSO hybridization patterns using the CANTYPE reverse hybridization assay. Sequences were determined by cloning/sequencing. DRB1*1333 is identical to DRB1*1303 except for a single nucleotide substitution (ACC→AAC), changing codon 77 from Thr to Asn. This polymorphism is typical for DRB1*03 alleles. DRB1*0426 is identical to DRB1*0401 except for a single nucleotide substitution (GCC→ACC) at codon 58, changing the encoded Ala to Thr. DRB5*0109 is identical to DRB5*0101, except for a single nucleotide substitution (GAC→AAC), changing codon 70 from Asp to Asn. Both latter polymorphisms were so far undetected in DRB alleles. DRB1*1333 could have arisen from a gene conversion event, but DRB1*0426 and DRB5*0109 most likely were generated by point mutation events. For all 3 alleles, the sequence was confirmed by the original hybridization pattern (DRB1*1333) or by hybridization to a newly designed probe (DRB1*0426 and DRB5*0109). Ethnic backgrounds were Lebanese for DRB1*1333 and Caucasian for DRB1*0426 and DRB5*0109.     

HLA-A*02 allele frequencies and haplotypic associations in Koreans

We have investigated the frequencies of HLA-A*02 alleles and their haplotypic associations with HLA-B and -DRB1 loci in 439 healthy unrelated Koreans, including 214 parents from 107 families. All of the 227 samples (51.7%) typed as A2 by serology were analyzed for A*02 alleles using polymerase chain reaction (PCR)-low ionic strength-single-strand conformation polymorphism (LIS-SSCP) method. A total of six different A*02 alleles were detected (A*02 allele frequency 29.6%): A*0201/9 (16.6%), *0203 (0.5%), *0206 (9.3%), *0207 (3.0%), and one each case of *0210 and *02 undetermined type. Two characteristic haplotypes showing the strongest linkage disequilibrium were A*0203-B38-DRB]*1502 and A*0207-B46-DRB1*0803. Besides these strong associations, significant two-locus associations (P<0.001) were observed for A*0201 with B61, DRB1*0901 and DRB1*1401, and for A*0206 with B48 and B61. HLA haplotypes carrying HLA-A2 showed a variable distribution of A*02 alleles, and all of the eight most common A2-B-DR haplotypes occurring at frequencies of > or =1% were variably associated with two different A*02 alleles. These results demonstrate that substantial heterogeneity is present in the distribution of HLA-A*02 alleles and related haplotypes in Koreans.     

New HLA-A*11 allele,A*1112, identified by sequence-based typing

In this report, we describe the identification of HLA-A*1112, a novel HLA-A*11 allele found in two Italian families. The new allele was detected during routine HLA typing by a polymerase chain reaction sequence-specific primer and was confirmed by high-resolution sequencing-based typing. The nucleotide sequences of HLA-A*1112 exons 2 and 3 are identical to HLA-A*11011 except for a single nucleotide substitution in codon 90 (GAC-->GCC).     

Five newly identified HLA alleles: A*0310, A*2907, B*4435, Cw*0206, Cw*0506, and confirmation of A*3106, B*3924, Cw*0314, DRB1*0322, and DRB1*1433 alleles

A number of HLA alleles have been newly identified. This concerns HLA-A*0310, A*2907, B*4435, Cw*0206, Cw*0506, of which Cw*0206 was found in three unrelated individuals, all B*4002 positive. Some other alleles are also presented but confirm earlier detected sequences: A*3106, Cw*0314, DRB1*0322, and DRB1*1433. Moreover, we identified B*3924 in a bone marrow transplant recipient and in five of six unrelated stem cell donors, selected for this patient. In all cases, B*3924 was found on a haplotype combining A*0201, B*3924, Cw*0701, and DRB1*1303. The observation of this extended haplotype is of importance for the selection for stem cell transplantation. Cells expressing B*3924 and B*4435 were typed by serology as B39 and B44, respectively. Cells expressing HLA-A*0310 do not express A3 but type as A-Blank.     

Identification of a novel HLA-DQB1*06 allele, DQB1*0618

We report here the identification of a novel DQB1*06 allele, DQB1*0618, found in a bone marrow donor. The new allele was detected during routine DNA-based HLA typing by an ambiguous pattern of probe hybridization, obtained by polymerase chain reaction using sequence-specific oligonucleotides (PCR-SSO). Molecular cloning and sequencing confirmed that the new allele is identical to DQB1*0609 at exon 2 except for 3 nucleotide substitutions at positions 353, 356 and 367, also found in other alleles. These nucleotide changes may explain its anomalous reactivity.     

Identification of the novel allele HLA-DRB1*1137 which probably originated from DRB1*11011: implications for mismatch with its ancestor allele at bone marrow transplantation

The identification of the new allele HLA-DRB1*1137, which was found in a Caucasian individual, is described. In the sequence analysis the new allele differs from DRB1*11011 by position 227 (T>A) which is located in exon 2. At the protein level, the new allele has one amino acid difference compared to DRB1*1101 (Phe47Tyr). Residue 47 is likely to contribute to the peptide binding site of HLA-DR11 and thus to be important for peptide binding. However, as phenylalanine and tyrosine have very similar physical and chemical features allogenicity in case of mismatch at bone marrow transplantation may be weak.