HLA-Ⅰ类抗原的组织配型基因芯片的建立及应用

目的:应用基因芯片技术进行北方汉族人群HLA-Ⅰ类抗原中分辨度分型研究,建立稳定的HLA检测芯片.方法:采用寡核苷酸芯片分型方法,依据第十三届国际组织相容性工作会议报告及相关文献,同时考虑遗传的连锁不平衡,及强脊炎、幼年型糖尿病等与HLA密切相关的遗传病等因素,选择了中国人群基因频率较高的等位基因,根据HLA-Ⅰ类不同基因亚型的独特序列,完成了探针的设计与筛选,最后设计了122条探针(HLA-A56条,HLA-B66条)制成基因分型芯片.采用带荧光标记的引物,用合适的PCR方法扩增HLA-Ⅰ类抗原上的多态性区域,产物与芯片上探针杂交.杂交结果经荧光扫描并用特定软件分析判断阳性探针,以此确定样品基因型.结果:所有样本的HLA-Ⅰ类抗原基因分型均获成功.此中分辨度探针可分出598个Ⅰ类抗原等位基因,可检出Ⅰ类抗原特异性57个.结论:基因芯片用于HLA-Ⅰ类抗原分型可行.其分辨率高,特异性强,可用于HLA基因分型、骨髓移植、器官移植的HLA配型、与HLA有密切关系的遗传性疾病的人群筛查.     

可溶性HLA—Ⅰ类抗原及临床意义的研究进展

ＨＬＡ是一类复杂的人类遗传多肽性系统,其研究工作在医学实践中有十分重要的意义,其中,ＨＬＡ－Ｉ类抗原在移植排斥反应中起着重要作用,是组织排斥应答的主要抗原,同时对细胞毒Ｔ细胞起约束作用,ＨＬＡ－Ｉ类抗原除了以膜抗原形式存在于细胞膜表面外,目前也已从人类的血清和淋巴液,尿液及乳汁中检出,称为可溶性ＨＬＡ抗原。本文综述了ｓＨＬＡ－Ｉ分子的分泌、结构、检测,在免疫调节及在自身免疫病、器官移植,感染等生理     

HLAⅠ、Ⅱ类抗原的组织配型基因芯片的建立及应用

目的应用基因芯片技术进行北方汉族人群HLAⅠ、Ⅱ类抗原中分辨度分型研究,建立稳定的HLA检测芯片。方法采用寡核苷酸芯片分型方法,选择了中国人群基因频率较高的等位基因,同时考虑遗传的连锁不平衡,根据HLA-A、HLA-B、HLA-DR、HLA-DQB、HLA-DQA不同基因亚型的独特序列,完成了探针的设计与筛选,共设计了213条探针(HLA-A 56条,HLA-B 66条,HLA-DQA 22条,HLA-DQB 38条,HLA-DR 31条)制成基因分型芯片。采用带荧光标记的引物,用合适的PCR方法扩增HLAⅠ、Ⅱ类抗原上的多态性区域,产物与芯片上探针杂交。杂交结果经荧光扫描并用特定软件分析判断,以此确定样品基因型。结果所有样本的HLAⅠ、Ⅱ类抗原基因分型均获成功。此中分辨度探针可分出598个Ⅰ类抗原等位基因,511个Ⅰ类抗原等位基因,可检出Ⅰ类抗原特异性57个,Ⅱ类抗原特异性30个。结论基因芯片用于HLAⅠ、Ⅱ类抗原分型可行。其分辨率高、特异性强,可用于HLA基因分型、骨髓移植、器官移植的HLA配型、与HLA有密切关系的遗传性疾病的人群筛查。     

人类白细胞抗原-A基因芯片分型研究

目的 探索人类白细胞抗原-A（HLA-A）基因芯片分型，为器官移植临床配型服务。方法 根据中国汉族南方人常见的HLA-A位点基因及其多态性的独特序列，设计并合成48条特异性的寡核苷酸分型探针，将其点在玻片上，制成芯片。基因组DNA通过组间特异性引物扩增，并用荧光素Cy5标记。标记后的产物与结合在芯片上的探针进行杂交，通过荧光扫描仪获得杂交产生的荧光信号值，再经过计算机软件自动分析，确定样品的HLA-A基因亚型。用该方法对120份样本进行HLA-A基因分型。结果 120份待检样本，其中6份因PER无产物，不能分型。1份信号杂乱，不能分型。其余113份样本分型成功。实际检出A抗原特异性结果为A2（含A203）：56；A11（含A1101）：52；A24：33；Al：8；A30（含A3001）：7；A33：21；A26：1；A29：2；A31：3；A68：2；A3：9；A32：1。未检出A＊3002基因型。整个检测耗时约4．5h。芯片检测的重复率为100％。结论 HLA-A基因芯片是一种理想的分型方法，具有特异性高、重复性好、操作简便、所需样本量少、结果判读容易、一次可作多份样本的优点，适合临床器官移植配型应用。     

用竞争结合法检测HLAⅠ类分子抗原呈递能力

目的：建立弱酸处理后荧光素标记肽竞争结合法分析MHCⅠ类分子抗原呈递能力的方法，并评估其实用性。方法：pH2．7～3．1的柠檬酸缓冲液对B淋巴母细胞进行短时处理后，即用IMDM培养液中和pH，然后加入β2微球蛋白、荧光素标记的9肽及竞争肽共同孵育，FACs检测细胞表面的平均荧光强度，以达到50％抑制所需的竞争肽浓度作为衡量竞争肽与MHC分子结合能力的指标。结果：通过不同pH的柠檬酸缓冲液处理、处理后不同时间加β2微球蛋白和，或荧光素标记肽、加入不同稀释度的竞争肽等角度，对方法进行评估，结果显示本方法操作简便、结果可靠、非特异性吸附小。结论：在排除其它MHCⅠ类分子的干扰后，本方法适合在国情条件下广泛开展MHCⅠ类分子抗原呈递能力及T细胞肽表位筛选等研究。     

沈阳汉族人群HLA－DR、DQ、DP的DNA分型研究

使用ＰＣＲ／ＳＳＯ方法对９４名沈阳汉族健康人群进行了ＨＬＡ第Ⅱ类抗原等位基因的完全分型。共发现６６种等位基因，基中ＤＲＢ１２８种，ＤＲＢ３３种，ＤＲＢ５４种，ＤＱＡ１８种，ＤＱＢ１Ｉ３种，ＤＰＢ１１０种。分析了ＤＲ－ＤＱ连锁的五位点单倍型，共发现３８种，其中２１种是在白人为主的人群中已发现过的。本研究提出了中国东北人群ＨＬＡ第Ⅱ类抗原等位基因的遗传基本情况，可用于疾病研究的对照和其他中国人群资料的比较。     

HLA—A,B血清学分型与DNA分型的比较

目的：比较１３６例样本ＨＬＡ－Ａ,Ｂ血清学分型与ＤＮＡ分型结果。方法：应用聚合酶链反应－序列特异性引物（ＰＣＲＳＳＰ）技术,设计３８对引物,检测常见的ＨＬＡ－Ａ,Ｂ基因。结果：１３６例样本中有６０例血清学分型与ＤＮＡ分型结构不符合（４４．１％）;ＨＬＡ－Ａ特异性血清学分型错误率在纯合子中分别占２３．３％与９．４％（共１１．２％）,在ＨＬＡ－Ｂ中分别占４７．４％与１８．４％（共２０．６％）;ＨＬＡ－Ａ特异性血清学分型假阴性６．６％,假阳性２．５％,错误指认特异性２．１％,ＨＬＡ－Ｂ错异性则分别为６．７％,３．６％,１０．３％。结论：ＩＬＡ－Ａ纯合子血清学分型错误率明显高于杂合子（Ｐ〈０．０５）;ＨＬＡ－Ｂ纯合子血清学分型错误率也明显高于杂合子（Ｐ〈０．００５）;ＨＬＡ－Ｂ特异性血清学分型错误率显著高于ＨＬＡ－Ａ特     

HLA-A towards a high-resolution DNA typing

Abstract: Sequencing-based typing (SBT) and sequence-specific oligonucleotide probing (PCR-SSOP) are DNA-based typing approaches to identify HLA-A alleles. In this study PCR-SSOP SBT have been evaluated and considered to reach a high-resolution typing. Based upon serological typing, 32 genomic samples were typed by SBT and PCR-SSOP. Three main clusters of resolution could be defined. The advantage of the PCR-SSOP approach is the possibility to type numerous samples in a short time. SBT minimizes the number of ambiguous heterozygous combinations and often allows direct detection and identification of new alleles.     

Accurate typing of HLA-A antigens and analysis of serological deficiencies

We are reporting the results of HLA-A typing by PCR-SSOP complemented by PCR-SSP of samples obtained from the National Marrow Donor Program (NMDP). These samples were a representative group from 2486 tested in duplicate by serology. A total of 390 samples gave HLA-A discrepant results. Comparing the molecular typing results of 238 samples (samples with available DNA) with the serological typing results, 54 homozygotes and 184 heterozygotes produced a total of 422 assignments by molecular methods. We found assignment discrepancies in 147/422 (35%) in laboratory 1 and 144/422 (34%) in laboratory 2 (a combined group of 4 NMDP laboratories; laboratory 1 is not included). The serological discrepancies found were of 3 categories: a) false negatives, b) incomplete typing (discrepancies due to the level of resolution within a cross-reactive or CREG group) and c) false positives. Major problems were identified using serology for typing HLA-A antigens: a) inability to identify all WHO-recognized specificities, more frequently in non-Caucasians or in HLA-A specificities known to be found more frequently in non-Caucasians for laboratory 1 and incorrect assignments of A19 specificities in laboratory 2, b) incorrect assignments in cells with poor viability and c) false-positive assignments in homozygotes. We propose a possible strategy to type HLA-A specificities with two steps: a) a minimum of serology for typing specificities for common CREG groups: A1, A2, A3, A11, A9, A10, A28, A19. However, a given laboratory can determine the level of serological assignments needed as a first step. And b) molecular methods to identify splits: A23, A24, A29, A30, A31, A32, A33, A34, A36, A66, A74 and A80. The technique described is useful for large-scale bone marrow donor typings for cells with poor viability, and for resolving ambiguous results including false-positive assignments of homozygous cells.     

Detection of HLA-A*24 null alleles by DNA typing methods

Abstract: A number of cases have been identified (seven unrelated individuals from the Northern Ireland bone marrow donor registry and two family groups) where an HLA-A*24 allele fails to express the normal HLA-A24 antigen. Family information has revealed common haplotypes with respect to each non-expressed allele indicating that the occurrence of these mutations has been a recent event. Two methods for the clinical typing of these alleles have been evaluated - PCR-SSOP and PCR-SSCP analysis.     

HLA-A,B,C and DR antigens in psoriasis

51 psoriasis vulgaris patients and 93 controls were tested for HLA-A,B,C and DR antigenic frequencies. Significant increases of B17, Cw6 and DR7 were documented in the patient group, as well as a decreased frequency of DR1. The significance of these findings is discussed. DR7 occurred more often together with Cw6 in psoriasis patients than in controls, which might suggest that there are at least two interacting HLA linked genes which increase the disease susceptibility and possibly one DR1 linked gene associated with resistence to the disease.     

HLA-DR and HLA-A, B, C typing of human fetal tissue

In anticipation of clinical trials of fetal pancreas transplantation we have investigated the feasibility of performing HLA-DR and HLA-A, B, C typing on fetal lymphoid cells other than PBL. Using the standard NIH microcytotoxicity test modified for HLA-DR typing it was possible to demonstrate HLA-DR antigens on subpopulations of bone marrow cells and splenocytes but not on thymocytes or hepatocytes. In contrast, HLA-A, B, C antigens could be detected on all four tissues. Excellent HLA-DR typing, confirmed by maternal typing, was obtained for 19 fetuses (14 to 23 weeks old) using bone marrow cells isolated by two-fold purification on discontinuous Percoll buoyant density gradients. Similar purification of splenocytes resulted in weak reactions with anti-DR sera; however, adherent splenocytes recovered from nylon wool columns proved to be primarily DR-bearing and also provided excellent DR typing. As a corollary to these results, non-adhering splenocytes depleted of DR-bearing cells were ideal for HLA-A, B, C typing since spurious reactions due to DR antigens were greatly diminished, whereas strong specific reactions were obtained with anti-HLA-A, B, C sera. Despite weaker reactions with HLA-A, B, C antisera obtained for thymocytes, reliable HLA-A, B, C typing could be obtained when results from thymocytes were evaluated together with typing from bone marrow cells or splenocytes. The possible benefits of fetal HLA typing for fetal pancreas transplantation are discussed.