白细胞介素-17和叉头状螺旋转录因子3在子痫前期发病机制中的作用及剖宫产术后自控镇痛对其表达的影响

目的 探究白细胞介素-17(IL-17)和叉头状螺旋转录因子3(Foxp3)在子痫前期发病机制中的作用,对比重度子痫前期产妇剖宫产术后,超声引导下双侧腹横肌平面(TAP)阻滞复合静脉泵自控镇痛(PCIA)与硬膜外镇痛对疼痛控制及外周血中IL-17和Foxp3表达水平的影响.方法 筛选2016年2月至2020年2月苏州市...     

TAP1*rs1057141基因多态性与新疆维吾尔族变应性鼻炎的相关性研究

目的初步探讨抗原提呈转运蛋白1(transporter associated with antigen processing 1,TAP1)基因rs1057141位点多态性与新疆维吾尔族变应性鼻炎(allergic rhinitis,AR)易感性的关系。方法采用病例-对照研究方法,随机选择新疆医科大学第一附属医院耳鼻喉科维吾尔族住院患者150例(病例组)和门诊健康体检者150例(对照组),采用SNaPshot SNP分型技术检测300个样本rs1057141基因位点多态性,并与NCBI基因库中世界其他种族人群进行比较。结果基因型G/G、G/A、A/A在病例组中的频率分别为4.00%、35.33%、60.67%,在对照组中的频率分别为8.67%、40.00%、51.33%,两组间基因型频率分布差异无统计学意义(P>0.05);等位基因G和A的频率在对照组为28.67%、71.33%,在病例组为21.67%、78.23%,两组间等位基因频率分布差异有统计学意义(P<0.05)。维吾尔族TAP1*rs1057141基因型及等位基因与世界其他种族人群相比较,差异均有统计学意义(P<0.05)。结论 TAP1*rs1057141多态性与新疆维吾尔族变应性鼻炎易感性相关,可能是易感基因。新疆地区维吾尔族人群中TAP1*rs1057141位点基因型频率分布与世界其他种族人群比较均有差异。     

TAP1真核表达载体的构建及其对GES-1细胞HLA-I分子表达的影响

目的:构建抗原加工相关转运蛋白TAP1真核表达载体,并观察其对HLA-I分子表达的影响。方法:采用基因重组技术,构建含人TAP1基因全长的pcDNA3.1/V5-His-TAP1真核表达质粒,并采用细胞转染、RT-PCR、Western blot以及流式细胞术(FCM)观察TAP1转染对胃黏膜上皮(GES-1)细胞HLA-I分子表达的影响。结果:以人外周血单个核细胞总RNA为模板,经RT-PCR反应获得人全长TAP1基因,以pcDNA3.1/V5-HisB为载体,经酶切、连接、转化等基因重组技术,构建了含人TAP1基因全长的pcDNA3.1/V5-His-TAP1质粒,并经测序结果证实。以GES-1作为靶细胞进行转染,经RT-PCR和Westernblot证实,转染后TAP1基因表达明显增加,细胞适于所构建的TAP1质粒的转染。进一步检测了TAP1转染对GES-1细胞HLA-I类分子表达的影响。结果发现,TAP1转染组HLA-A、HLA-B、HLA-C(重链)在mR-NA水平表达明显增加,β2m(轻链)mRNA水平无明显影响。FCM及Western blot检测结果表明,TAP1转染可以上调HLA-I蛋白的表达。结论:成功构建了TAP1真核表达质粒,细胞转染后TAP1表达的增加,可引起细胞表面HLA-I分子表达的相应增加,从而证实了TAP1在HLA-I抗原表达以及抗原递呈途径中的重要作用。     

Control of cross-presentation during dendritic cell maturation

The initiation of most cytotoxic immune responses requires MHC class I-restricted presentation of internalized antigens to CD8(+) T lymphocytes, a process called cross-presentation. In dendritic cells (DC), the only antigen-presenting cells that activate naive T cells, cross-presentation is particularly efficient after internalization of opsonized antigens or immune complexes, which are cross-presented through a proteasome- and transporter associated with antigen processing (TAP)-dependent MHC class I antigen presentation pathway. We now show that FcgammaR-mediated cross-presentation is tightly regulated during DC maturation. Cross-presentation increases soon after activation by lipopolysaccharides, and it is then inhibited in fully mature cells. The initial induction of cross-presentation results from an increase of both antigen internalization and delivery to the cytosol, and from a slight rise in the activity of the proteasome and TAP. The subsequent block of cross-presentation in mature DC is a consequence of the selective down-modulation of antigen internalization and cytosolic delivery, while proteasome and TAP activities continue to rise. Therefore, FcgammaR-mediated cross-presentation is regulated during DC maturation by the selective control of antigen internalization and transport to the cytosol.     

Presentation of endogenous viral proteins in association with major histocompatibility complex class II: On the role of intracellular compartmentalization,invariant chain and the TAP transporter system

Major histocompatibility complex (MHC) class II-associated antigen presentation is mainly linked to processing of exogenous antigens upon cellular uptake by endocytosis, but has also been observed for endogenously sythesized antigens. We have studied the MHC class II-associated presentation of the endogenously synthesized membrane associated glycoprotein (GP) and the cytosolic nucleoprotein (NP) of lymphocytic choriomeningitis virus (LCMV) in professional antigen presenting cells (APC) of mice. Since LCMV is a noncytopathic virus and minimally affects cellular protein synthesis. it is a convenient virus for the study of antigen presentation. In contrast, most other studies assessing class II-associated presentation of endogeneously synthesized viral antigens used cytolytic viruses such as vaccinia, measles and influenza virus, which drastically interfere with host cell functions. In addition, most studies were performed using non-professional APC. We found that class II-associated presentation of endogenously synthesized membrane associated LCMV-GP was efficient and could not be inhibited by chloroquine or leupeptin. Neither the transporter associated with processing (TAP) system nor the invariant chain (Ii) were significantly involved in this process. In contrast, MHC class II-associated presentation of endogenously synthesized cytosolic LCMV-NP was not observed even in Ii-deficient APC. Thus, MHC class II loading of endogenously synthesized LCMV-GP apparently does not require processing in acidie endosomal compartments as defined by chloroquine and leupeptin insensitivity. Furthermore, although the TAP molecules transport peptides of up to 15 amino acids in length, which potentially could bind to MHC class II molecules in the endoplasmic reticulum, such a process apparently does not occur for either the glycoprotein or the nucleoprotein. Therefore, the subcellular localization of an endogenously synthesized protein influences crucially whether or not MHC class II loading can occur independently of the acidic compartments usually involved in MHC class II loading.     

Analysis of allelic variation of the TAP2 gene in sarcoidosis

Sarcoidosis is a systemic granulomatous disease and the DRB1 gene of the DR subregion has been implicated for determining the genetic susceptibility to the disease. We evaluated the allelic variation of the TAP2 gene using the PCR-RFLP method as well as the mismatched PCR-RFLP method in 82 Japanese patients with sarcoidosis and 92 healthy controls. A new allele, TAP2*0103 and a new polymorphic variation at codon 577 in addition to TAP2*0101, TAP2*0102 and TAP2*0201 have been recognized in the Japanese subjects. No significant differences were observed in the frequencies of any TAP2 alleles or dimorphism at codon 577 between the patients and healthy controls. Polymorphic variation of the TAP2 gene does not confer the susceptibility to sarcoidosis.     

肝癌H-22细胞膜抗原肽提取物对小鼠免疫功能的影响及其抑瘤作用

目的应用小鼠肝癌H-22细胞膜相关抗原肽(TAP)提取物免疫小鼠,观察其对小鼠自身移植肿瘤生长及免疫学参数的影响,为制备肿瘤疫苗提供实验依据.方法采用微酸洗脱法制备分子量≤3000 Da的细胞膜TAP提取物,皮下免疫小鼠,检测胸腺细胞增殖反应、T细胞亚组百分数的变化,脾细胞Con A反应性、IL-2和IFN-γ活性、CTL杀伤活性的变化及抑瘤效应.结果 TAP提取物免疫后,移植肿瘤的发生率降低(P＜0.01),平均出现时间延迟(P＜0.001),生长速度减慢;同时,脾细胞Con A反应性(P＜0.01)、IFN-γ(P＜0.05)和IL-2分泌活性和CTL杀伤活性(P＜0.05)不同程度增强;胸腺细胞3H-TdR自发掺入率(P＜0.05)及CD4 和CD8 T细胞百分数(P＜0.05)也有不同程度增高.结论小鼠肝癌H-22细胞膜TAP提取物具有免疫原性,能有效激发免疫系统功能,抑制自身移植肿瘤的生长.     

Major histocompatibility complex class I presentation of ovalbumin peptide 257–264 from exogenous sources: protein context influences the degree of TAP-independent presentation

Peritoneal macrophages from C57BL/6 mice process antigens from bacteria or coated on polystyrene beads for presentation by major histocompatibility complex (MHC) class I molecules. To investigate this antigen processing pathway, peritoneal macrophages from homozygous TAP1^−/− mice, which lack the transporter associated with antigen processing (TAP) and are defective in presenting endogenous antigens on MHC class I, were used. TAP1^−/− or C57BL/6 macrophages were co-incubated with either bacteria or polystyrene beads containing the 257–264 epitope from ovalbumin [OVA(257–264)], which binds the mouse class I molecule K^b. The source of the OVA(257–264) epitope was either the Crl-OVA(257–264) (Crl-OVA) fusion protein, the maltose binding protein (MBP)-Crl-OVA fusion protein, native OVA or bacterial recombinant OVA (rOVA); Crl-OVA, MBP-Crl-OVA and rOVA were each expressed in bacteria, and Crl-OVA and MBP-Crl-OVA purified from bacterial lysates and native egg OVA were coated onto polystyrene beads. The data reveal that peritoneal macrophages from C57BL/6 and TAP1^−/− mice can process bacteria expressing Crl-OVA, MBP-Crl-OVA and rOVA as well as beads coated with native OVA, purified Crl-OVA, and purified MBP-Crl-OVA and present OVA(257–264) for recognition by OVA(257–264)/K^b-specific T hybridoma cells, albeit with different relative processing efficiencies. The processing efficiency of TAP1^−/− macrophages co-incubated with bacteria or beads containing Crl-OVA or MBP-Crl-OVA was reduced approximately three to five times compared to C57BL/6 macrophages, but OVA(257–264) was presented 100 times less efficiently when the source of OVA(257–264) was full-length OVA. Chloroquine inhibition studies showed a differential requirement for acidic compartments in C57BL/6 versus TAP1^−/− macrophages, which also depended upon the source of the OVA (257–264) epitope (Crl-OVA versus full-length OVA). These data suggest that TAP1^−/− and C57BL/6 macrophages may process Crl-OVA and full-length OVA in different cellular compartments and that the protein context of the OVA(257–264) epitope influences the extent of TAP-independent processing for MHC class I presentation.     

Translocation of long peptides by transporters associated with antigen processing (TAP)

The major histocompatibility complex (MHC)-encoded transporters associated with antigen processing (TAP) translocate peptides from the cytosol into the lumen of the endoplasmic reticulum (ER) where they associate with MHC class I molecules. The length of class I-binding peptides is usually 8–11 amino acids, but examples of significantly longer peptides have been described. The preferred lengths and upper and lower size limits for peptides translocated by TAP have not been determined in detail because in the currently used test systems, peptides are subject to proteolytic degradation. In the present study, three sets of individual peptides or partially randomized peptide libraries ranging between 6 and 40 residues were used that contained a radiolabeled tyrosine and a consensus sequence for ER-specific N-glycosylation at opposite ends, thus ensuring that only nondegraded peptides were monitored in the transport/glycosylation assay. For three different transporters, rat TAP1/2^a, rat TAP1/2^u and hTAP, the most efficient ATP-dependent transport was observed for peptides with 8–12 amino acids. Hexamers and longer peptides of up to 40 amino acids were also translocated, albeit less efficiently. For two of the three sets of peptides analyzed, rat TAP1/2^a showed a less stringent length selection than rat TAP1/2^u and human TAP. The superior transport of the decamer of the TNKT . Y series was not due to faster degradation or less efficient glycosylation of shorter or longer length variants. A binding assay with TAP-containing microsomes revealed a high affinity for the radiolabeled decamer (K_D = 580 nM), while other length variants were clearly inferior in their binding affinities. Thus, TAP binds and preferentially translocates peptides with a length suitable for binding to MHC class I molecules, but peptides that are considerably longer may also be substrates. About 10⁵ peptide binding sites per cell equivalent of microsomes were determined, providing an estimate for the number of TAP complexes in the ER membrane.     

Expression and genetic analysis of transporter associated with antigen processing in cervical carcinoma

OBJECTIVE: Transporter associated with antigen processing (TAP) loss causes human leukocyte antigen (HLA) class I downregulation which is frequently found in cervical carcinomas and their precursors. HLA class I molecules activate T-cells by antigen presentation and are therefore essential for immunological surveillance. To add to the hitherto limited knowledge of molecular mechanisms underlying TAP loss, we investigated TAP expression, loss of heterozygosity (LOH) and possible TAP mutations. METHODS: Twenty-three cervical carcinomas and adjacent precursor lesions were stained with HLA-A-, HLA-B/C-, beta2 -microglobulin-, TAP1- and TAP2- antibodies. In order to separate tumour and non-tumour cells, cervical carcinoma samples were sorted by flow-cytometry and were subsequently analysed for LOH with 3 markers in the TAP region on chromosome 6p21.3. Mutation analysis of the complete TAP1 gene was performed. RESULTS: Aberrant TAP1 expression was detected in 10/23 cervical carcinoma lesions and in 5/10 adjacent cervical intraepithelial neoplasia (CIN) lesions. All the lesions with low TAP expression also had reduced HLA class I expression. LOH was found in 7 out of 10 lesions with TAP loss. Mutation analysis detected no aberrations, but identified a polymorphism in the 5'-untranslated region (UTR) of the TAP1 gene in two lesions. CONCLUSIONS: This study shows that defective TAP expression in cervical carcinoma is often associated with LOH in the TAP region but not with mutations in the TAP1 gene.