HLA-Cw与疾病关系研究进展

HLA-Cw为经典的HLA-I类基因,其编码产物的组织分布极为广泛,并且具有高度的多态性。HLA-Cw与K IR分子组成特异性信号传导系统,调节NK细胞活性,在机体抗感染免疫、肿瘤免疫、移植免疫中发挥重要作用。本文对HLA-Cw分子结构、基因多态性及与疾病关系研究进展作一综述。     

汉滩病毒核蛋白CTL表位肽联合不同免疫佐剂的免疫学特性研究

目的:研究汉滩病毒(HTNV)核蛋白细胞毒性T淋巴细胞(CTL)表位肽联合不同免疫佐剂免疫C57BL/6小鼠后的免疫学特性,确立一种免疫效果良好的多肽免疫C57BL/6小鼠方案。方法:分别用氢氧化铝、弗氏佐剂和脂质体作为免疫佐剂与汉滩病毒核衣壳蛋白上的CTL表位肽段混合,经皮下注射免疫C57BL/6小鼠,共免疫3次,每次间隔2周;免疫结束后分离小鼠脾细胞,并分别采用ELISPOT和CTL杀伤试验进行检测。结果:HTNV核蛋白CTL表位肽联合弗氏佐剂加脂质体组小鼠脾细胞分泌IFN-γ能力和CTL杀伤能力优于其他各实验组(P0.01)。结论:HTNVCTL表位肽联合弗氏佐剂加脂质体免疫C57BL/6小鼠效果最佳,可为HTNV多肽疫苗的免疫策略提供参考。     

哇巴因对人血管内皮细胞死亡和钠泵α1、β1,亚单位表达的影响

目的：研究钠泵抑制剂哇巴因（ouabain）对人血管内皮细胞死亡的影响及其作用机制。方法：以脐静脉内皮细胞系ECV304为靶细胞,应用MTT实验检测哇巴因对细胞生长的作用 采用Hoechst33342/PI双荧光染色、透射电镜和DNA琼脂糖凝胶电泳等分析细胞死亡特征,半定量RT-PCR法检测钠泵α1和β1亚单位mRNA的表达。结果：哇巴因以浓度和作用时间依赖的方式抑制ECV304细胞生长。10μmol/L哇巴因作用24 h,引起细胞坏死 0.1μmol/L哇巴因作用24～48 h,细胞明显脱落,细胞间连接丧失,细胞出现染色质凝集、分布于核膜内缘、DNA裂解等凋亡特征。哇巴因能明显上调ECV304细胞钠泵α1亚单位mRNA的表达,下调β1亚单位mRNA表达,且两者均呈时间依赖性。结论：哇巴因能诱导人血管内皮细胞ECV304死亡,其上调钠泵α1亚单位表达、下调β1亚单位表达,可能与亚单位介导信号传递、降低细胞黏附有关。     

汉滩病毒感染诱导热休克蛋白70表达

为了解汉滩病毒感染后细胞的应激反应及HSP70的表达与病毒复制的关系,在汉滩病毒A9株感染Vero-E6细胞后,用免疫组织化学及核酸分子原位杂交法,对细胞HSP70基因的表达进行了检测.结果表明,汉滩病毒感染细胞4h后即可诱导Vero-E6细胞表达HSP70,表达可持续至感染后5d,且HSP70在细胞内的分布也有改变.提示汉滩病毒可直接诱导HSP70的高表达.     

汉滩病毒包膜糖蛋白糖基化位点突变体重组假病毒的构建及初步鉴定

目的：为进一步研究汉坦病毒包膜糖蛋白的糖基化与病毒的感染性和免疫原性等的关系,构建含有汉滩病毒（HTNV）囊膜糖蛋白（GP）糖基化位点突变体的重组假病毒。方法：利用定点突变的方法,分别突变了HTNV 76-118株的5个N-糖基化位点并克隆入慢病毒表达载体,与包装质粒共转染293T细胞,构建5株重组假病毒。感染HEK293细胞后,进行RT-PCR鉴定及免疫荧光检测。结果：经测序显示构建的含有N-糖基化位点突变体的5个重组假病毒原序列中的天冬酰胺（N）均被置换为谷氨酰胺（Q）。RT-PCR结果显示5个重组假病毒均有HTNV GP基因的表达。免疫荧光检测5个重组假病毒均可表达HTNV的Gn和Gc蛋白。结论：成功构建了含有HTNV包膜糖蛋白糖基化位点突变体的5个重组假病毒,分别命名为rLV-M1、rLV-M2、rLV-M3、rLV-M4和rLV-M5。本研究为明确N-糖基化对汉坦病毒生物学活性的影响提供了有利的研究工具,并为汉坦病毒疫苗及致病机理的进一步研究打下了一定的基础。     

脂联素在高糖孵育血管内皮细胞中的表达调节

目的:探讨脂联素(APN)在高糖孵育血管内皮细胞中的表达调节及意义.方法:用不同浓度葡萄糖(5.5、11、22及33mM)孵育人脐静脉内皮细胞(HUVECs),2天后收集细胞和上清液.用实时荧光定量RT-PCR方法检测细胞中APN、肿瘤坏死因子α(TNFα)和过氧化物酶体增生物激活受体γ(PPARγ)的mRNA表达,用ELISA方法检测细胞上清液中APN和TNFα分泌情况.结果:随培养液中葡萄糖浓度的升高,HUVECs中APN的mRNA表达及上清中APN蛋白含量降低(p<0.05),TNFα的mRNA表达及上清中TNFα蛋白含量增加(p<0.05),HUVECs中PPARγ的mRNA表达降低(p<0.05),且组间比较差异均有统计学意义(p<0.05).结论:高糖诱导血管内皮细胞保护性细胞因子APN表达分泌下降,可能是高糖诱导的血管内皮细胞功能损害的重要机制之一.     

汉滩病毒核蛋白与热休克蛋白GRP94、HSP27的相互作用

为研究汉滩病毒(Hantaan virus,HTNV)感染诱导乳鼠脑组织热休克蛋白GRP94、HSP27与病毒蛋白的相互关系,选出生2—3d的昆明乳鼠实验性感染汉滩病毒,取8d后发病乳鼠脑组织部分制石蜡切片,用免疫组化结合共聚焦显微镜检测组织中病毒抗原及GRP94、HSP27的表达,部分制匀浆液,用ELISA、免疫共沉淀方法分析病毒抗原和GRP94、HSP27的关系。结果示汉滩病毒感染诱导乳鼠脑组织神经细胞高表达GRP94且与细胞内病毒抗原有共定位关系,但未见HSP27诱导高表达;免疫共沉淀显示汉滩病毒核心抗原(HINV—NP)与GRP94、HSP27呈非共价复合物形式存在。该结果为进一步探讨HSPs在病毒感染复制中的作用以及抗病毒感染方面提供了有意义的实验资料。     

汉滩病毒核蛋白与热休克蛋白GRP94、HSP27的相互作用

为研究汉滩病毒(Hantaan virus, HTNV)感染诱导乳鼠脑组织热休克蛋白GRP94、HSP27与病毒蛋白的相互关系,选出生2～3d的昆明乳鼠实验性感染汉滩病毒,取8d后发病乳鼠脑组织部分制石蜡切片,用免疫组化结合共聚焦显微镜检测组织中病毒抗原及GRP94、HSP27的表达,部分制匀浆液,用ELISA、免疫共沉淀方法分析病毒抗原和GRP94、HSP27的关系.结果示汉滩病毒感染诱导乳鼠脑组织神经细胞高表达GRP94且与细胞内病毒抗原有共定位关系,但未见HSP27诱导高表达;免疫共沉淀显示汉滩病毒核心抗原(HINV-NP)与GRP94、HSP27呈非共价复合物形式存在.该结果为进一步探讨HSPs在病毒感染复制中的作用以及抗病毒感染方面提供了有意义的实验资料.     

炎症促进大鼠动脉粥样硬化初期内皮功能病变机制研究

目的:观察炎症因素诱导大鼠动脉粥样硬化发病过程中对血管内皮细胞的影响。方法:实验分为单纯高脂对照组和炎症组,分别腹腔注射给予无菌医用液体石蜡和酵母多糖(Zym,20mg/kg,1次/3天)。所有大鼠均喂食含3%胆固醇的高脂饲料,共8周。透射电镜观察主动脉超微结构;应用定量PCR法测定腹主动脉组织中诱导型一氧化氮合酶(iNOS)mRNA、血管细胞粘附分子(VCAM)-1 mRNA、以及基质金属蛋白酶7(MMP7)mRNA的表达。结果:炎症组可见游走于内膜下层的平滑肌细胞和和吞噬脂质颗粒的单核细胞,单纯高脂对照组仅见内皮细胞损伤和退行性变,未见内膜下层形成泡沫细胞,AS样病变较炎症组轻。与对照组相比,炎症组动脉壁iNOS mRNA表达降低,VCAM-1 mRNA及MMP7 mRNA标大量显著升高。结论:炎症刺激能够损伤动脉血管内皮细胞,诱导炎症因子释放增加,促进动脉粥样硬化的发生。     

膜型基质金属蛋白酶-1在不同内皮细胞株中的表达差异

为研究膜型基质金属蛋白酶-1（membrane-type matrix metalloproteinase-1, MT1-MMP）在血管生物学中的作用机制,比较了3株常用的内皮细胞株：人微血管内皮细胞株HMEC-1、人脐静脉内皮细胞株ECV304和EAhy926中MT1-MMP及与其功能相关的MMP-2,TIMP-2的表达差异.实时PCR 和流式细胞术检测HMEC-1、EAhy926和ECV304中MT1-MMP/MMP-2/TIMP-2的表达,明胶酶谱法分析各细胞株上清中MMP-2的酶活.实时PCR结果显示,3株细胞均表达MT1-MMP与TIMP-2,MT1-MMP在EAhy926中表达最高,TIMP-2在ECV304中表达最高,而仅在EAhy926中检测到MMP-2的表达.流式细胞术和酶谱的结果与PCR结果基本一致.MT1-MMP和MMP-2在典型的大血管内皮细胞株EAhy926中高表达可能与该细胞独特的来源、表型特点和功能有关.     

Identification of HLA-Cw6.02 and HLA-Cw7.01 allele-specific binding motifs by screening synthetic peptide libraries

Unlike HLA-A and HLA-B, few peptide epitope motifs have been reported for HLA-C molecules. However, a number of cytotoxic T-lymphocyte epitopes derived from tumor antigens that bind to HLA-C molecules have been described. Here we report peptide-binding motifs for both HLA-Cw6.02 and HLA-Cw7.01 molecules. Recombinant human HLA molecules were generated and used to screen combinatorial 9mer peptide libraries. Complexes of HLA molecules properly folded and associated with ₂-microglobulin and peptides were identified using a conformation-specific HLA class I antibody conjugated to alkaline phosphatase. In the presence of substrate, peptide beads can be readily isolated and microsequenced to determine peptide identity. Of the peptides that bound to HLA-Cw6.02 and HLA-Cw7.01, 19 and 18 peptides, respectively, were sequenced, allowing motif identification for each C allele. This is the first report of an HLA-Cw7.01 peptide motif and extends the findings of Falk et al. [(1993) Proc Natl Acad Sci USA 90:12005] for an HLA-Cw6.02 motif. Anchoring amino acids for the HLA-Cw6.02 motif were phenylalanine or tyrosine in position (P)1, arginine in P2, and an aliphatic/aromatic residue at P9. Anchoring residues for HLA-Cw7.01 were positively charged amino acids in P1 and P2. Unlike most other HLA molecules, we were unable to assign P9 an anchoring residue, and we suspect that HLA-Cw7.01 binds peptides in an unconventional manner. Additionally, preferred amino acids were identified for both molecules. Identification of HLA-Cw6.02 and HLA-Cw7.01 peptide-binding motifs makes a significant contribution to the C allele peptide-binding motifs and will allow investigators to predict, design, and test HLA-Cw6.02 and HLA-Cw7.01 engineered peptides for immunotherapy.     

Human beta 2-microglobulin specifically enhances cell-surface expression of HLA class I molecules in transfected murine cells

Sequential transfections of P815 murine mastocytoma cells with class I gene encoding either HLA-Cw3, HLA-A3, or HLA-B7 H chain and subsequently with a human beta 2-microglobulin gene were performed to evaluate the relative efficiency of human and murine beta 2-microglobulins in promoting the cell-surface expression of HLA-class I molecules. A 6-, 11-, and 40-fold specific enhancement of the cell-surface expression of HLA-Cw3, HLA-A3, and HLA-B7 molecules, respectively, was observed in cells co-transfected with human beta 2-microglobulin gene. This effect was attributed to a more efficient association of HLA H chains with human than with murine beta 2-microglobulin, which apparently allowed a more rapid transport of the HLA molecules from the endoplasmic reticulum to the Golgi apparatus.     

HLA-Cw*04 and hepatitis C virus persistence

In studies of acute hepatitis C virus (HCV) infection, the early host immune response is one of the determinants of viral persistence. The class I human leukocyte antigens (HLA), which present foreign antigen to cytolytic T cells, are integral components of this response. We hypothesized that the highly polymorphic HLA genes affect the outcome of an HCV infection. To test this hypothesis, we molecularly typed 231 persons with well-documented clearance of an HCV infection and 444 matched persistently infected persons. HLA-A*1101 (odds ratio [OR], 0.49; 95% confidence interval [95% CI], 0.27 to 0.89), HLA-B*57 (OR, 0.62; 95% CI, 0.39 to 1.00), and HLA-Cw*0102 (OR, 0.43; 95% CI, 0.21 to 0.89) were associated with viral clearance, whereas HLA-A*2301 (OR, 1.78; 95% CI, 1.01 to 3.11) and HLA-Cw*04 (OR, 1.78; 95% CI, 1.21 to 2.59) were associated with viral persistence. HLA-Cw*04 is in strong linkage disequilibrium with HLA-B*53 and HLA-B*35, but only HLA-B*53 (OR, 1.70; 95% CI, 0.95 to 3.06) and the Cw*04-B*53 haplotype (OR, 1.76; 95% CI, 0.94 to 3.26) were weakly associated with viral persistence. HLA-B*53 has similar, but not necessarily identical, binding specificity to some HLA-B*35 subtypes (B*35-Px group). The association with the B*35-Px group was less strong than with HLA-B*53 alone. The association of HLA-Cw*04 with HCV persistence was codominant (two copies of the gene were more strongly associated with persistence than one copy). However, HLA-Cw*04 was not associated with HCV RNA levels among the persistently infected individuals. Since Cw*04 is a ligand for the killer immunoglobulin-like receptors on natural killer cells, these cells may be involved in recovery from HCV infection. Further investigation is needed to understand the relationship between class I alleles and HCV clearance.     

Analysis of the HLA-Cw3-specific cytotoxic T lymphocyte response of HLA-B7 X human beta 2m double transgenic mice

The cytolytic responses of either normal (non transgenic), HLA-B7 (single transgenic) or HLA-B7 x human beta 2 microglobulin (double transgenic) DBA/2 mice induced by transfected HLA-Cw3 P815 (H-2d) mouse mastocytoma cells were compared, to evaluate whether the expression of an HLA class I molecule in responder mice would favor the emergence of HLA-specific, H-2-unrestricted CTL. Only 8 of 300 HLA-Cw3-specific CTL clones tested could selectively lyse HLA-Cw3-transfected cells in an H-2-unrestricted manner, all having been isolated after hyperimmunization of double transgenic mice. These clones also lysed HLA-Cw3+ human cells. Unexpectedly, the lysis of the human but not that of the murine HLA-Cw3 cells was inhibited by Ly-2,3-specific mAb. Despite significant expression of HLA-B7 class I molecules on transgenic lymphoid cells, including thymic cells, limiting dilution analysis and comparative study of TCR-alpha and -beta gene rearrangements of the eight isolated clones (which suggested that they all derived from the same CTL precursor) indicated that the frequency of HLA-Cw3-specific H-2 unrestricted cytotoxic T lymphocytes remained low (even in HLA-B7 x human beta 2-microglobulin double transgenic mice). This suggests that coexpression of HLA class I H and L chain in transgenic mice is not the only requirement for significant positive selection of HLA class I-restricted cytotoxic mouse T lymphocytes.     

Human leukocyte antigen (HLA) complex and anti-thyroidal antibodies in Graves' disease

The study aimed at: 1) assessing occurrence of HLA-A, HLA-B and HLA-C antigens in patients with Graves' disease in comparison with control group of healthy individuals; 2) determining relationship between circulating serum antimicrosomal and antithyroglobulin antibodies and selected HLA complex antigens. Human leukocyte antigens A, B, and C were detected with serological technique using cytotoxicity test. Thyroidal antimicrosomal and antithyroglobulin antibodies were titrated with radioimmunological solid phase technique while anti-membrane antibodies with immunoenzyme technique. The study involved 50 patients with Graves' disease and 50 healthy individuals. HLA-B8, HLA-B15, HLA-B35, and HLA-Cw3 antibodies were detected more frequently in patients with Graves' disease than in the healthy individuals. Antimicrosomal and antithyroglobulin antibodies were detected in the same group in 76% and 58% of patients, respectively whereas anti-membrane antibodies in 92% of patients. Comparison of the occurrence of thyroidal antimicrosomal and antithyroglobulin antibodies with the presence of HLA-B8, HLA-B35, HLA-B15, and HLA-Cw3 antigens did not show statistically significant correlation between these two parameters.     

High Resolution Human Leukocyte Antigen Class I Allele Frequencies and HIV-1 Infection Associations in Chinese Han and Uyghur Cohorts

Background

Host immunogenetic factors such as HLA class I polymorphism are important to HIV-1 infection risk and AIDS progression. Previous studies using high-resolution HLA class I profile data of Chinese populations appeared insufficient to provide information for HIV-1 vaccine development and clinical trial design. Here we reported HLA class I association with HIV-1 susceptibility in a Chinese Han and a Chinese Uyghur cohort.

Methodology/Principal Findings

Our cohort included 327 Han and 161 Uyghur ethnic individuals. Each cohort included HIV-1 seropositive and HIV-1 seronegative subjects. Four-digit HLA class I typing was performed by sequencing-based typing and high-resolution PCR-sequence specific primer. We compared the HLA class I allele and inferred haplotype frequencies between HIV-1 seropositive and seronegative groups. A neighbor-joining tree between our cohorts and other populations was constructed based on allele frequencies of HLA-A and HLA-B loci. We identified 58 HLA-A, 75 HLA-B, and 32 HLA-Cw distinct alleles from our cohort and no novel alleles. The frequency of HLA-B*5201 and A*0301 was significantly higher in the Han HIV-1 negative group. The frequency of HLA-B*5101 was significantly higher in the Uyghur HIV-1 negative group. We observed statistically significant increases in expectation-maximization (EM) algorithm predicted haplotype frequencies of HLA-A*0201-B*5101 in the Uyghur HIV-1 negative group, and of Cw*0304-B*4001 in the Han HIV-1 negative group. The B62s supertype frequency was found to be significantly higher in the Han HIV-1 negative group than in the Han HIV-1 positive group.

Conclusions

At the four-digit level, several HLA class I alleles and haplotypes were associated with lower HIV-1 susceptibility. Homogeneity of HLA class I and Bw4/Bw6 heterozygosity were not associated with HIV-1 susceptibility in our cohort. These observations contribute to the Chinese HLA database and could prove useful in the development of HIV-1 vaccine candidates.