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人Ⅰ型丙氨酸氨基转移酶原核表达、表位分析及其抗体制备
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摘要
丙氨酸氨基转移酶(Alanine aminotransferase)俗称谷丙转氨酶,它是糖异生和氨基酸代谢过程中一个至关重要的酶,主要分布在肝脏组织中。当肝组织损伤因为病毒性肝炎、非酒精性脂肪肝、肝硬化及药物因素损伤时,肝细胞中的ALT释放入血,使血清中ALT显著增高。因此,在过去的50多年间,临床上一直把血清中ALT作为反映肝功能的一个重要的生物标志物。通过对血清中ALT的检测,可以反映出肝脏功能是否损伤以及损伤的程度。
     近年来发现人体中ALT有3种同功酶,ALT_1、ALT_2和ALT_2-2。实验研究发现,ALT_1与ALT_2有着共同的催化活性,而ALT_2-2未发现有催化活性。ALT_1主要分布在肝脏、骨骼肌和肾脏组织中,亚细胞定位于胞浆和内质网;ALT_2主要分布在心肌细胞和骨骼肌中,而在肝脏和肾脏组织中未见表达,亚细胞定位于线粒体和内质网,在胞浆中不存在。因此,血清中ALT_1水平比总ALT能更特异的反应肝脏功能状态。
     目前,临床上对ALT的检测主要是通过检测总的ALT酶活性来完成的。这种方法虽然操作相对简便,结果准确,但要依赖常规的生化检测仪器,不能满足在献血现场对献血员ALT的快速筛查。
     我们拟建立基于免疫学诊断技术的检测方法,对血清中ALT_1的实际含量进行快速检测,以满足献血现场对血源筛查的需要,并且可以更准确、特异地反应肝脏功能。为进一步研发ALT_1免疫学体外诊断试剂奠定基础。本课题拟制备出ALT_1特异的抗体。
     目的:
     原核表达截短的ALT_1蛋白,用它免疫新西兰大白兔后,制备出特异的ALT_1多克隆抗体;用合成的表位肽免疫BALB/c小鼠,制备特异的ALT_1单克隆抗体。为研发ALT_1免疫学体外诊断试剂奠定基础。
     方法:
     1.利用分子克隆技术构建ALT_1截短表达载体pCold-TF-ALT_1。
     2.将表达载体转化入BL21(DE3)表达宿主菌,经IPTG诱导及SDS-PAGE分析表达形式后,用镍离子亲和层析法纯化融合蛋白,再经HRV-3C蛋白酶酶切后,应用凝胶过滤法去除标签蛋白,进而得到不带标签的截短ALT_1蛋白。
     3.通过B细胞抗原表位预测软件分析ALT_1的抗原表位,综合分析后,选取两段肽MC-15和CK-17交予公司合成,并分别偶联KLH以增加免疫原性。
     4.用纯化的截短ALT_1蛋白免疫新西兰大白兔,制备ALT_1多克隆抗体。
     5.用人工合成偶联有KLH的MC-15、CK-17表位肽分别免疫BALB/c小鼠,通过杂交瘤技术制备ALT_1单克隆抗体。
     结果:
     1.成功构建ALT_1的截短表达质粒,通过PCR和双酶切鉴定得到与预期大小一致的基因片段,同时通过基因测序分析证实完全一致,并无移码突变。
     2.通过镍离子亲和层析纯化后得到较纯的重组截短表达蛋白,融合蛋白再通过HRV-3C蛋白酶酶切后经分子筛纯化得到不带标签的目的蛋白。
     3.用纯化的ALT_1截短表达蛋白免疫新西兰大白兔后,制备出了特异性好、效价高的ALT_1多克隆抗体。
     4.用人工合成偶联有KLH的MC-15、CK-17表位肽免疫BALB/c小鼠,建立了多株稳定分泌ALT_1单克隆抗体的杂交瘤细胞株,通过腹水诱生法制备了腹水型ALT_1单克隆抗体,间接酶联免疫吸附试验法证明了腹水效价可达106,并可识别人血清中的ALT_1蛋白。
     结论:
     重组表达的截短融合蛋白经镍离子亲和层析纯化后,得到的融合蛋白再通过HRV-3C蛋白酶酶切后应用分子筛得到目的蛋白,用此蛋白制备了ALT_1特异性的多克隆抗体;用合成的表位肽制备了特异性的单克隆抗体。为进一步研发ALT_1免疫学体外诊断试剂奠定基础。
Alanine aminotransferase(ALT),also named glutamate pyruvate transaminase, is a key enzyme for gluconeogenesis and amino acid metabolism . ALT is mainly distributed in tissue of the liver. An elevated serum ALT activity is regarded as evidence of liver damage, including hepatitis、nonalcoholic steatohepatosis、fatty liver、cirrhosis and drug hepatoxicity. Analysis of serum ALT activity levels is routinely used for detecting liver injury, a biomarker that has been in use for more than 50 years.The serum ALT is mainly detected by the method of it’s activity in the practice of medicine. Although the method for enzymic activity detection is relatively simple and accurate during operation, but to rely on conventional biochemical testing equipment, can not meet the need for rapid detection of ALT on-site the source of blood donation. And the activity assay just reflects the total serum ALT activity, rather than the actual quality of ALT, test results will reflect more exactly to the liver state.
     Three forms of ALT have been identified, ALT_1、ALT_2andALT_2-2. Experimental study found that, ALT_1 and ALT_2 share a common catalytic activity, while ALT_2-2 was not found to have catalytic activity. ALT_1 was mainly in the liver, skeletal muscle and kidney tissue, subcellular localization in cytoplasm and endoplasmic reticulum; while ALT_2 was mainly in cardiac cells and skeletal muscle, no expression in liver and kidney tissue, subcellular in the mitochondria and endoplasmic reticulum, not exist in the cytoplasm.
     Therefore, we intend to establish a diagnosis method based on immunological detection techniques, to detect the actual content of serum ALT_1 and meet the need for blood screening of blood donation on the spot. In order to establish in vitro diagnostic method for ALT_1, we project to prepare the specific antibody of ALT_1.
     Objective:
     After acquireing the truncated ALT_1 protein by prokaryotic expression system , we immunized New Zealand white rabbits for the preparation of the specific ALT_1 polyclonal antibody.Simultaneously, we immuned BALB / c mices with the synthetic peptides,and prepared the specific ALT_1 monoclonal antibody. Made the foundation to the development of in vitro diagnostic test of ALT_1.
     Methods:
     1. We constructed expression vector of the truncated ALT_1 by the technique of molecular cloning using the pCold-TF vector.
     2. Expression vector with ALT_1 were transformated into E.coil BL21(DE3),then the recombinant proteins were induced by IPTG ,after beening analyzed the express pattern by SDS-PAGE, proteins were purified by Ni2+ affinity chromatography,then cut the TF tag-protein by HRV-3C protease,in the end ,we acquired the truncated ALT_1 protein by gel filtration.
     3. Considering results coming from different B cell epitope prediction softwares,two epitopes-MC15 and CK17, were got to prepare the ALT_1 monoclonal antibody.We Submitted the sequences to the company to synthesis peptides and coupled with the protein carrier KLH to increase the immunogenicity.
     4. ALT_1 polyclonal antibody was prepared after the rabbits being immunied with purified truncated protein.
     5. ALT_1 monoclonal antibody was prepared after BALB/c mices were immunized with the coupled peptides -MC15 and CK17.
     Results:
     1.Truncated ALT_1 expression plasmid was constructed successfully after the identification by PCR and restriction enzyme digestion,which appeared a gene fragment consistent with the expected size. Also confirmed the same by gene sequence analysis, without any frameshift mutations.
     2.Pure recombinant protein was acquire after being purified by Ni2+ affinity chromatography.And truncated ALT_1 protein was purified by gel filtration after being digested by HRV-3C prolease.
     3. High specificity and titer ALT_1 polyclonal antibody was acquired after rabbits being immunized with purified truncated protein.
     4. Hybridoma cells were acquired after BALB/c mices being immunized with synthesis peptides. And ALT_1 monoclonal antibody was acquired after mices being injected with hybridoma cells though abdominal cavity.Also the McAb titer was detected up to 106 by ELISA. Certainly,the McAb could recognize the native ALT_1 in the serum.
     Conclusions:
     Pure truncated ALT_1 protein was acquired after being purified by Ni2+ affinity chromatography and gel filtration. High specificity and titer ALT_1 polyclonal antibody and monoclonal antibody were acquired after rabbits or BALB/c mices being immunized with purified truncated protein or coupled peptides,which made a foundation to the development of a rapid in vitro diagnostic test strip of ALT_1.
引文
[1] P. Felig, The glucose–alanine cycle, Metabolism 22 (1973) 179–207.
    [2] T. Ota et al., Nat. Genet. 36 (2004) 40–45.
    [3] Glinghammar B et al, Detection of the mitochondrial and catalytically active alanine aminotransferase in human tissues and plasma[J] Int J Mol Med. 2009 May,23(5):621-31.
    [4] Lindblom P, Rafter I et al, Isoforms of alanine aminotransferases in human tissues and serum—Differential tissue expression using novel antibodies[J]. Arch Biochem Biophys. 2007 Oct 1;466(1):66-77.
    [5] Josef Ozer, Marcia Ratner et al.The current state of serum biomarkers of hepatotoxicity[J]. Toxicology .245 (2008) 194–205.
    [6] Ruhl CE, Everhart JE. Relation of elevated serum alanine aminotransferase activity with iron and antioxidant levels in the United States[J]. Gastroenterology
    [7] 2003,124:1821-1829.
    [8] Lozano M, Cid J, Bedini JL,et al. Study of serum alanine-aminotransferase levels in blood donors in Spain. Haematologica[J].1998;83:237-239.
    [9] Johnston DE. Special considerations in interpreting liver function tests[J].Am Fam Physician 1999;59:2223-2230.
    [10] Saxena S, et al.A review of donor alanine aminotransferase testing: implications for the blood donor and practitioner[J].Arch Pathol Lab Med 1989;113:767-771.
    [11] Giboney PT. Mildly elevated liver transaminase levels in the asymptomatic patient[J]. Am Fam Physician 2005;71:1105-1110.
    [12] Chen CH, Huang MH, Yang JC, Nien CK, Yang CC, Yeh YH, et al.Prevalence and etiology of elevated serum alanine aminotransferase level in an adult population in Taiwan[J]. J Gastroenterol Hepatol 2007;22:1482-1489.
    [13] Clark JM, et al. The prevalence and etiology of elevated aminotransferase levels in the United States[J]. Am J Gastroenterol 2003;98:960-967.
    [14] Browning JD, et al. Prevalence of hepatic steatosis in an urban population inthe United States: impact of ethnicity[J]. HEPATOLOGY 2004;40:1387-1395.
    [15] Bacon BR. Treatment of patients with hepatitis C and normal serum aminotransferase levels[J]. HEPATOLOGY 2002;36:S179-S184.
    [16] Marcellin P, Levy S, Erlinger S. Therapy of hepatitis C: patients with normal aminotransferase levels[J]. HEPATOLOGY 1997;26:133S–136S.
    [17] Ozer J, Ratner M, et al.The current state of serum biomarkers of hepatotoxicity[J]. Toxicology 2008;245:194-205.
    [18] Dufour DR, Lott JA et al.Diagnosis and monitoring of hepatic injury. II.Recommendations for use of laboratory tests in screening, diagnosis, and monitoring[J]. Clin Chem 2000;46:2050-2068.
    [19]中华人民共和国国家标准.献血者健康体检要求.[S] GB18467.2001.9-12.
    [20]中华人民共和国卫生部.中国输血技术操作规程血站部分[M].天津:天津科学技术出版社,1997:3.
    [1]司徒镇强,吴军正.细胞培养[M].现世界图书出版社,1996:232-242.
    [2]秦璐璐,耿建萍.杂交瘤细胞染色体制备及生物学意义初探[J].医学理论与实践2008年第21卷第4期375-376.
    [3] Kohler G, Milstein C. Continuous cultures of fused cells secreting antibody of predefined specificity[J]. Nature 1975; 256 (5517): 495-7
    [4] Chinen J, Shearer WT. Advances in basic and clinical immunology in 2010 J Allergy Clin Immunol[J]. 2011 Feb;127(2):336-41.
    [5] Sabine Geisse, Hermann Gram ,Eukaryotic Expression Systems: A Comparison[J]. PROTEIN EXPRESSION AND PURIFICATION.1996. 8, 271–282
    [6] Li Liu, Shao Zhong , Rongze Yang ,Expression, purification, and initial characterization of human alanine aminotransferase (ALT) isoenzyme 1 and 2 in High-five insect cells[J]. Protein Expression and Purification2008 .60.225–231
    [7] Picard F, Dressaire C, Girbal L, Cocaign-Bousquet M. Examination of post-transcriptional regulations in prokaryotes by integrative biology[J].C R Biol. 2009 Nov;332(11):958-73.
    [8] Westhof, E., Altschuh, D., Moras, D., Bloomer,A.C., Mondragon, A., Klug, A., and Van Regenmortel,M.H.V. Correlation between segmental mobility and the location of antigenic determinants in proteins[J]. Nature 1984.311:123-126.
    [9] John E. Coligan, James P. Tam, and Jun Shao Production of Antipeptide Antisera [M].Current Protocols in Neuroscience (1997) 5.6.1-5.6.21
    [1] Van Regenmortel MH,Synthetic peptides versus natural antigens in immunoassaya[J] Ann Biol Clin (Paris) 1993, 51:39-41.
    [2] Barlow DJ, Edwards MS, Thornton JM,Continuous and discontinuous protein antigenic determinants[J]. Nature 1986,322:747-748.
    [3] Langeveld JP, martinez-Torrecuadrada J, et al,Characterisation of a protective linear B cell epitope against feline parvoviruses[J]. Vaccine 2001,19:2352-2360.
    [4] El Kasmi KC, Muller CP, New strategies for closing the gap of measles susceptibility in infants: towards vaccines compatible with current vaccination schedules[J]. Vaccine 2001, 19:2238-2244.
    [5] 5. Sabhanini L, Manocha M, et al,Developing subunit immunogens using B and T cell epitopes and their constructs derived from F1 antigen of Yersinia pestis using novel delivery vehicles[J]. FEMS Immunol Med Microbiol 2003, 1579:1-15.
    [6] Kieber-Emmons T, Luo P, Qiu J et al, Vaccination with carbohydrate peptide mimotopes promotes anti-tumor responses[J]. Nat Biotechnol 1999, 17:660-665.
    [7] Selo I, Clement G, Bernard H, et al,Allergy to bovine beta-lactoglobulin:specificity of human IgE to tryptic peptides[J]. Clin Exp Allergy 1999, 29:1055-1063.
    [8] Odorico M, Pellequer JL, BEPITOPE: predicting the location of continuous epitope and patterns in proteins[J]. J Mol Recognit 16:20-22.
    [9] Alix AJ, Predictive estimation of protein linear epitopes by using the program PEOPLE[J]. Vaccine 1999, 18:311-314.
    [10] Hoop JP,WoodKR.Prediction ofproteinantigenic determinants from anlino acid 8eqIIences[J].Immunology 1981,78(6):3824.
    [11] Kyte J,DolittleR F,A Simplemethodfordisplaying hydropathic character of a protein[J].J Mol Biol 1983,157(1):105.
    [12] Tsche H,Modern methods in protein and nucleic acid research[M].1th.New York:Walter de Gruger Berlin 1990.1231.
    [13] Welling GW,et al,Prediction of sequential antigenic regions in proteins[J].FEBS Lctt 1985.188 (2):215.
    [14] Karplus PA ,Schultz G E,Prediction of chain flexibility in proteins[J],Immunology1985,72(2):212.
    [15] [15] Gershoni JM ,Stem B,Venisova G,Combinatorial libraries,epitope structure and the prediction of conformations[J].Immu-nol Today 1997,18(5):108.
    [16]来鲁华.蛋白质的结构预测与分子设计[M].第1版.北京:北京大学出版社,1993,49。
    [17] Saha , S , Bhasin , M , and Raghava , G. P. S. Bcipep: A database of B-cell epitopes .BMC Genomics 6 ,79[M] .Biochemistry 2005.25 .5425 -5432 .
    [18] Levitt , M. Conformational preferences of amino acids in globular proteins[M] . Biochemistry 1978.17 , 4277 -4285 .
    [19] Parker,J,Guo,D,and Hodges,R. New hydrophilicity scale derived from highperformance liquid chromatography peptide retention data: correlation of predicted surface residues with antigenicity and X-rayderived accessible sites [M]. 1986. Biochemistry 25 ,,5425 -5432.
    [20] Pontoppidan Larsen , J. E, et al,Improved method for predicting linear B-cell epitopes[M] . 2006.Immunome Res. 2 ,2 .
    [21] McSparron , et al. A novel computational information resource for immunobiology and vaccinology [J]. 2003.J. Chem. Inf. Comp. Sci. 43 , 1276- 1287.
    [22] Bairoch A, Apweiler R: The SWISS-PROT protein sequence database and its supplement TrEMBL in 2000[J]. Nucleic Acids Res 2000, 28:45-48.
    [23] Westbrook J, Feng Z, Jain S, et al,The Protein Data Bank: unifying the archive[J]. Nucleic Acids Res 2002, 30:245-248.
    [24] Bhasin M, Singh H, Raghava GPS: MHCBN: A comprehensive database of MHC binding and non-binding peptides[M]. Bioinformatics 2003, 19:666-667.
    [25] An LL, Whitton JL,A multivalent minigene vaccine, containing B-cell, cytotoxic T-lymphocyte, and Th epitopes from several microbes, induces appropriate responses in vivo and confers protection against more than one pathogen[J]. J Virol 1997, 71:2292-2302.
    [26] Obeid OE, Stanley CM, Steward MW: Immunological analysis of the protective responses to the chimeric synthetic peptide representing T- and B-cell epitopes from the fusion protein of measles virus[J]. Virus Res 1996, 42:173-180.
    [27] Fernandez IM, Snijders A, et al,Influence of epitope polarity and adjuvants on the immunogenicity and efficacy of a synthetic peptide vaccine against Semliki Forest virus[J]. J Virol 1993, 67:5843-8.
    [28] Todryk SM, et al,Effect of route of immunisation and adjuvant on T and B cell epitope recognition within a streptococcal antigen[J]. Vaccine 1998, 16:174-180.
    [29] 29. Andersen , P. H. Prediction of residues in discontinuous B cell epitopes using protein 3D structures [M]. 2006.Protein Sci. 15 , 2558 - 2567 .
    [30] Xiao Y, Lu Y, Chen YH: Epitope-vaccine as a new strategy against HIV-1 mutation[J]. Immunol Lett 2001, 77:3-6.
    [31] Wu HC, Yeh CT, Huang YL, Tarn LJ, Lung CC: Characterization of neutralizing antibodies and identification of neutralizing epitope mimics on the Clostridium botulinum neurotoxin type A[M]. Appl Environ Microbiol 2001, 67:3201-3207.
    [32] Meng J, Dai X, Chang JC, et al,Identification and characterization of the neutralization epitope(s) of the hepatitis E virus[J]. Virology 2001, 288:203-211.
    [33] Corcoran A, Mahon BP, Doyle S: B cell memory is directed toward conformational epitopes of parvovirus B19 capsidproteins and the unique region of VP1[J]. J Infect Dis 2004, 189:1873-1880.

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