中国佤族人群MBL基因SNP及其单倍型与基因型的研究

甘露聚糖结合凝集素（mannan-binding lectin，MBL）通过激活补体凝集素途径和调理吞噬作用清除病原体及受感染细胞，在机体天然免疫中起关键作用。已发现MBL基因上存在至少20个单核苷酸多态性（SNP）位点，仅其中6个SNP位点对MBL血清水平有较大的影响，     

中国白族人群MBL基因SNP及其单倍型与基因型的研究

目的：研究中国云南白族人甘露聚糖结合凝集素（MBL）基因单核苷酸多态性（SNP）及其单倍型与基因型。方法：对MBL基因启动子区SNP位点-550G／C（称H／L等位基因）、-221C／G（X／Y）、＋4C／T（P／Q）已明确的白族DNA样本，采用序列特异性引物．多聚酶链反应技术检测结构基因第一外显子点突变CGT52TGT、CCC54GAC和CCA57CAA（分别称为D、B、C等位基因，野生型即A），并分析MBL基因的单倍型与基因型。结果：只检出GGC54GAC点突变，其频率为0．100；检出的5种单倍型及其频率是：HYPA0．250、LXPA0．107、LYQA0．407、LYPA0．135、LYPB0．100；各基因型及其频率为：LYPA／LYPA0．043、LXPA／LYQA0．143、LYPA／LYPB0．014、HYPA／LYQA0．086、LYPA／LYQA0．157、HYPA／LYPA0．014、LYPB／LYQA0．143、HYPA／LYPB0．043、LXPA／LXPA0．014、HYPA／LXPA0．043、LYQA／LYQA0．143、HYPA／HYPA0．157。结论：中国白族人群MBL基因存在GGC54GAC点突变，单倍型以LYQA和HYPA为主，基因型则多见LYPA／LYQA、HYPA／HYPA、LX—PA／LYQA、LYPB／LYQA和LYQA／LYQA。     

中国维吾尔族人群MBL基因启动子及第一外显子区SNP及其单倍型与基因型研究

收集新疆维吾尔族自治区维吾尔族一般人群血标本,提取白细胞基因组DNA,以序列特异性引物-多聚酶链反应技术检测其甘露聚糖结合凝集素(MBL)基因启动子区单核苷酸多态性位点-550G/C(称H/L等位基因)、-221C/G(X/Y)、+4C/T(P/Q)和结构基因第一外显子点突变CGT52TGT、GGC54GAC和GGA57GAA(分别称为D、B、C等位基因,野生型即A等位基因),并分析其单倍型与基因型。发现MBL基因启动子区等位基因主要为L、Y、P,第一外显子等位基因只发现B,未检出C和D;检出5种单倍型,其频率分别是HYPA 0.282、LYPA 0.268、LXPA 0.260、LYPB 0.120、LYQA 0.070。检出12种基因型,其频率分别为HYPA/HYPA 0.183、LXPA/LXPA 0.141、LYPA/LYQA 0.113、LYPA/LYPA 0.112、LYPA/LXPA 0.085、HYPA/LYPA 0.085、LXPA/LYPB 0.085、HYPA/LXPA 0.070、HYPA/LYPB 0.042、LYPA/LYPB 0.028、LYPB/LYQA 0.028、YPB/LYPB 0.028。     

联合应用配体和单克隆抗体亲和层析纯化人血浆天然MBL蛋白

目的优化从人血浆分离纯化天然甘露聚糖结合凝集素（MBL）的方法。方法联合应用甘露聚糖-Sepharose 4B层析柱和抗人MBL-CRD单克隆抗体-Sepharose 4B层析柱，3次上柱亲和层析分离，分别用EDTA、D-甘露糖、Gly-HCl（pH2．4）溶液洗脱结合蛋白。以SDS-PAGE、Western blot和ELISA等技术鉴定纯化产物。结果所获纯化MBL为Mr28000和Mr32000肽链构成的功能性寡聚体，其纯度较高，可与配体甘露聚糖结合并有效凝集酵母菌，还能与U937细胞胶凝素受体结合。结论联合使用配体亲和层析和单克隆抗体亲和层析从血浆中分离纯化MBL，获得高纯度、高活性的天然MBL蛋白。     

中国白族、佤族和拉祜族人群MBL基因启动子区SNP的研究

目的:研究中国白族、佤族和拉祜族人群甘露聚糖结合凝集素(MBL)基因启动子区单核苷酸多态性(SNP)。方法:抽提人外周血白细胞基因组DNA,建立SSP-PCR及PCR-分子灯塔实时分析技术,检测MBL基因启动子区SNP位点-550(G/C,称H/L等位基因)、-220(G/C,X/Y等位基因)和 4 4(C/T,P/Q等位基因),分析其单倍型及基因型频率。结果:从 71例白族、73例佤族和 94例拉祜族人中,分别检出等位基因型LYP/LYP4例(5.6% )、4例(5. 5% )和 2例(2. 1% );HYP/LYQ6例 (8. 5% )、11例(15. 1% )和 12例 (12. 8% );LYP/LYQ21例 (29. 6% )、14例 (19.2% )和 51例 (54. 3% );LXP/LXP1例 (1. 4% )、2例 (2. 7% )和 0例;LYQ/LYQ10例(14. 1% )、14例 (19. 2% )、7例 (7. 4% );LXP/LYQ10例(14. 1% )、13例 (17. 8% )和 15例 (16. 0% );HYP/LYP4例(5. 6% )、3例(4. 1% )和 4例(4. 3% );HYP/LXP3例(4. 2% )、1例(1. 4% )和 0例;HYP/HYP12例(16. 9% )、11例(15. 1% )和 3例(3. 2% )。结论:中国白族、佤族、拉祜族普通人群之间,MBL基因启动子区等位基因L/H的分布存在差异(P<0. 01),X/Y和P/Q无统计学意义的差异(P>0. 05);各单倍型和各基因型的分布存在差异(P<0. 01);基因型LYP/LYQ和LXP/LYQ在 3个民族均有较高的分布,其总体频率分别达 36. 1%及 16.     

抗人甘露聚糖结合凝集素(MBL)单克隆抗体的制备、鉴定与检测方法的建立

目的 制备抗甘露聚糖结合凝集素(MBL)的单克隆抗体(McAb),建立免疫学检测方法.方法 以纯化MBL为抗原,免疫Ualb/c小鼠,制备单克隆抗体,鉴定其特性,建立并验证夹心ELISA定量检测法.结果 筛选出2株稳定分泌抗MBL的单抗杂交瘤细胞株,免疫球蛋白亚类均为IgG1.两单抗间抑制率＜50%,结合位点不同两单抗特异识别MBL.选择包被抗体B10浓度为8μg/mL,酶标抗体B3稀释度为1:500,建立夹心EIJSA定量检测法.该法检出范围为1～100 μg/mL,与其他抗原无交叉反应.重复性试验的批内批间变异均小于10%,回收率在101%～103%之间,cv小于7%.检测结果与国外试剂盒比较无显著差异.结论 制备的抗MBL单克隆抗体可用于MBL的免疫学检测.     

联合应用配体和单克隆抗体亲和层析纯化人血浆天然MBL蛋自

目的 优化从人血浆分离纯化天然甘露聚糖结合凝集素(MBL)的方法.方法 联合应用甘露聚糖-Sepharose4B层析柱和抗人MBL-CRD单克隆抗体-Sepharose 4B层析柱,3次上柱亲和层析分离,分别用EDTA、D-甘露糖、Gly-HCI(pH 2.4)溶液洗脱结合蛋白.以SDS-PAGE、Western blot和ELISA等技术鉴定纯化产物.结果 所获纯化MBL为Mr28 000和Mr32 000肽链构成的功能性寡聚体,其纯度较高,可与配体甘露聚糖结合并有效凝集酵母菌,还能与U937细胞胶凝素受体结合.结论 联合使用配体亲和层析和单克隆抗体亲和层析从血浆中分离纯化MBL,获得高纯度、高活性的天然MBL蛋白.     

甘露聚糖结合凝集素基因多态性与血清蛋白表达水平的关系

目的了解汉族儿童甘露聚糖结合凝集素(MBL)第一外显子54密码子的基因多态性以及与血清MBL蛋白水平的关系。方法用ELISA方法检测71例儿童血清MBL水平,用聚合酶链反应-限制性内切酶片段长度多态性分析(PCR-RFLP)方法对第一外显子54密码子基因多态性进行分析,比较不同基因型的血清蛋白质表达水平,并测定部分PCR产物的核苷酸序列。结果汉族人群MBL基因第1外显子54密码子3种基因型为GGC/GGC(77.5%)、GGC/GAC(18.3%)、GAC/GAC(4.2%),等位基因GGC(0.87)出现频率较GAC(0.13)高;低MBL水平基因型为GGC/GGC(12.5%)、GGC/GAC(75.0%)、GAC/GAC(12.5%),GGC/GAC基因型及等位基因GAC(0.50)频率较正常MBL组(0.03)高(P<0.005);GGC/GGC基因型的血清MBL的水平比GGC/GAC基因型明显增高[(3.67±2.10)μg/ml,(0.10±0.05)μg/ml,P<0.001],GGC/GGC基因型汉族人群血清水平较巴布亚新几内亚人[Papua NewGuinea,(2.45±0.82)μg/ml]明显增高(P<0.001);发现MBL第一外显子15、21、58、61密码子的突变。结论第一外显子第54密码子表现不同基因多态性分布,并对应不同的血清MBL水平。主要是GGC/GAC导致低血清MBL水平,但可能存在除52、54、57密码子外的第一外显子其他部位的基因多态性导致血清MBL蛋白质表达的种族差异。     

中国人MBL cDNA的克隆与序列分析

从中国汉族人胎肝组织提取ＲＮＡ,以ＲＴ－ＰＣＲ方法获得了编码含号顺序的全长甘露聚糖结合凝集素肽链的ｃＤＮＡ片段,将其与ｐＧＥＭ－Ｔ载体连接,转化大肠杆菌ＴＧ１,     

慢性丙型肝炎患者血浆内毒素和血清MBL变化及临床意义

目的:探讨了慢性丙型肝炎患者血浆内毒素和血清甘露聚糖结合凝集素(MBL)水平的变化及意义.方法:应用鲎试验和酶联法对31例慢性丙型肝炎患者进行了血浆内毒素和血清MBL测定,并与35名正常健康人作比较.结果:慢性丙型肝炎患者血浆内毒素和血清MBL水平均非常显著地高于正常人水平(P<0.01),且内毒素水平与MBL呈正相关...     

中国蒙古族人MBL基因启动子区SNP的研究

目的 研究中国蒙古族人群甘露聚糖结合凝集素(MBL)基因启动子区单核苷酸多态性(SNP)。方法 抽提人外周血白细胞基因组DNA，建立SSP-PCR及分子灯塔实时荧光PCR技术，检测MBL基因启动子区SNP位点-550(G／C，称H/L等位基因)、-220(G／C，X／Y等位基因)和 4(C／T，P／Q等位基因)，分析其单倍型及基因型频率。结果 从82人中检出等位基因型LYP／LYP4例(4．9％)，HYP／LYQ5例(6．1％)，LYP／LYQ35例(42．9％)，LXP／LXP1例(1．2％)，LYQ／LYQ11例(13．4％)，LXP／LYQ14例(17．1％)，HYP／LYP2例(2．4％)，HYP／LXP1例(1．2％)，HYP／HYP9例(11．0％)。结论 中国蒙古族人群MBL基因启动子区SNP等位基因型以LYP／LYQ、LXP／LYQ、LYQ／LYQ和HYP／HYP为主。     

Functional polymorphisms in the mannan-binding lectin 2 gene: effect on MBL levels and otitis media

BACKGROUND: Mannan-binding lectin (MBL) can bind to microorganisms, initiating the lectin pathway of complement activation. Aberrant MBL serum levels, caused by MBL2 gene polymorphisms, are a possible risk factor for recurrent infections. Within the 7 common MBL haplotypes, still considerable variation in MBL serum levels exists. OBJECTIVE: To investigate functional MBL levels and MBL2 polymorphisms in a large cohort of children with recurrent acute otitis media. METHODS: Twelve genetic variants in the MBL2 gene and functional MBL serum levels were determined in a cohort of children with recurrent acute otitis media. Haplotypes were constructed and associated with functional MBL serum levels and the number of otitis episodes in the previous year. RESULTS: The 7 common MBL2 haplotypes mainly determine the level of functional MBL in serum. In addition, the 3130G>C single nucleotide polymorphism, located in exon 4, further significantly influenced functional MBL levels within the LXPA haplotype. LXPA carriers with 3130G showed a significantly lower geometric mean functional MBL serum level of 0.19 mug/mL compared with 0.70 mug/mL in 3130C carriers (P = .026). Nonwild-type MBL2 carriers between 12 and 24 months had a significantly increased number of otitis episodes (5.1/y) compared with wild-type MBL2 carriers (4.1/y; P = .027). In older children, this association was not found anymore. CONCLUSION: Additional single nucleotide polymorphisms within the 7 common haplotypes can further explain the observed variation in functional MBL serum levels. MBL seems to be of particular clinical importance during early childhood, when maternally derived antibodies have waned, and protective adaptive immunity is not well developed yet. CLINICAL IMPLICATIONS: Single nucleotide polymorphisms in the promoter region, in exon 1, and in exon 4 of MBL2 contribute to increased risk for otitis media in children younger than 2 years.     

甘露聚糖结合凝集素突变型等位基因与SLE关联的研究

收集系统性红斑狼疮(SLE)患者和普通人群血标本,提取白细胞基因组DNA,以多聚酶链反应扩增目的基因片段,应用荧光探针杂交技术检测甘露聚糖结合凝集素(MBL)基因GGC54GAC、GGA57GAA和CGT52TGT点突变(分别称为等位基因B、C、D,所有突变型统称为O,野生型即A),分析MBL突变型等位基因与SLE及其严重程度的关系。74例SLE患者中,检出等位基因型A/B24例(32.4%)、B/B5例(6.8%)、A/C2例(2.7%)、A/D1例(1.4%)和B/C2例(2.7%),B、C、D的频率为0.250、0.028和0.007,突变型等位基因O的频率为0.285;95例对照组中,检出A/B22例(23.2%)、B/B2例(2.1%)和A/C1例(1.1%),B、C的频率分别为0.137和0.005,O的频率为0.142;两者比较,其突变等位基因的分布有显著差异(P<0.05)。等位基因型O/O纯合子SLE患者肾脏损害的发生率达100%,而A/A或A/O型病人分别为35.0%和37.0%,存在非常显著差异(P<0.01)。因此,MBL突变型等位基因是SLE的易感因素并与肾脏累及有关。     

The level of the serum opsonin, mannan-binding protein in HIV-1 antibody-positive patients.

The concentrations of mannan-binding protein (MBP) in consecutive samples from 10 HIV+ persons were estimated using an ELISA based on polyclonal rabbit anti-MBP. The changes in MBP with time were similar in HIV+ and HIV- persons, and did not appear to be of clinical significance. MBP was determined in a further 70 persons found HIV-1+ during a period of 2.5 years (1984-1986). Out of the total of 80 patients, 32 have by now died from AIDS. According to the serum level of MBP the HIV-infected persons were grouped into high (> 650 ng MBP/ml), intermediate (101-650 ng/ml), and low MBP (< 101 ng/ml). At the termination of the study the frequency of deaths/total in each of the groups were: high MBP, 14/39 (36%); intermediate MBP, 12/26 (46%); and low MBP, 6/14 (43%). There was no association between the MBP level of the individual and the progressive loss of CD4+ T cells, and the level of MBP was not predictive for the length of time between the detection of HIV antibodies and development of AIDS, nor for the duration of AIDS before death occurred. The number of HIV+ persons without detectable MBP (10%) was significantly higher than previously reported for healthy persons (2.4%, P = 0.027). The course of HIV infection does not seem to be influenced by the level of MBP, nor does the antimicrobial activity of MBP appear to affect the progression of AIDS. Further studies are required to substantiate the significance of absence of MBP in the susceptibility to HIV.     

甘露聚糖结合凝集素缺损与自身免疫性疾病

甘露聚糖结合凝集素(MBL)系胶原凝集素家族成员,是天然免疫系统中的重要分子。血清MBL浓度受其结构基因第一外显子几个点突变的影响和启动子区多态性的调控。MBL基因突变使其血清浓度降低,除导致调理吞噬缺损外,还与自身免疫性疾病如系统性红斑狼疮、类风湿性关节炎、干燥综合征、皮肌炎、克隆病、动脉炎等有关。     

Detection of structural gene mutations and promoter polymorphisms in the mannan-binding lectin (MBL) gene by polymerase chain reaction with sequence-specific primers

This study describes a new approach to the determination of all known mannan-binding lectin (MBL) mutations. The distribution of known variants of the MBL gene in a population of healthy unrelated Danes was determined and the genotype was correlated with the plasma MBL concentrations. The following genetic polymorphisms were studied: three point mutations in the promoter region at position -550 (H/L variants), -221 (X/Y variants), -70 (nt C or T), one point mutation in the 5' untranslated (UT) region at position +4 (P/Q variants) and three point mutations located at codons 52, 54 and 57 in exon 1 of the MBL gene, at nucleotide positions 223, 230 and 239, respectively. To perform genotyping, we designed sequence specific primers for a polymerase chain reaction (PCR-SSP). PCR-SSP is a powerful technique for the discrimination of alleles resulting from single base substitutions and is a widely used technique. Another major advantage of the PCR-SSP method is its ability to determine whether sequence motifs are in cis or trans. The frequencies of variants in exon 1 obtained by PCR-SSP were completely comparable to results obtained by previously described PCR methods, restriction fragment length polymorphism (RFLP) and site-directed mutagenesis (SDM). This PCR-SSP method is performed with standard laboratory equipment and has the capacity to detect all genetic variants in 100 samples in 2 days at an estimated total cost of GBP 11 per sample. Analysing the correlation between MBL haplotype and plasma MBL levels, we confirmed that three different structural variants, B, C and D and the promoter haplotypes HY, LY and LX have a dominant effect on the concentration of MBL. The HY haplotype is associated with the highest plasma concentration, the LY haplotype with intermediate levels and the LX haplotype with the lowest levels. The LX haplotype was found to be associated with very low levels of MBL similar to those found in association with the structural B genotype. The gene frequencies of variants in the MBL gene in the Danish population studied correspond to previous reports on Caucasian populations.