Vector Construction and Immunogenicity of S and N Gene DNA Vaccine for TGEV
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摘要:
目的 构建猪传染性胃肠炎病毒(Transmissible gastroenteritis virus, TGEV)S、N基因的DNA疫苗载体,并进行免疫原性试验,为猪传染性胃肠炎(Transmissible gastroenteritis, TGE)的防控和DNA疫苗研究提供技术支撑和基础数据。 方法 扩增S基因的A位点、D位点和N基因,并将N基因(单独)、A位点和D位点(融合)克隆至pCDNA3.1-His-C构建重组疫苗载体,运用生物信息学软件预测分析S(A-D)蛋白、N蛋白二级结构组成、三级构像、亚细胞定位和优势B细胞抗原表位。将构建成功的重组载体分别转染至PK-15细胞进行间接免疫荧光试验,运用共聚焦检测重组蛋白的表达分布情况。将重组疫苗载体单独或联合免疫小鼠,运用间接ELISA检测IgG抗体水平。 结果 扩增出S基因的A位点、D位点和N基因,大小分别为498、606、 1149 bp。构建了A位点与D位点(融合)、N基因(单独)的DNA疫苗重组载体p-S(A-D)-His和p-N-His。生物信息学软件预测分析发现TGEV感染宿主细胞时N蛋白主要定位于细胞核和线粒体,S(A-D)蛋白主要定位于细胞质和线粒体,S(A-D)蛋白具有7个优势B细胞抗原表位,N蛋白具有8个优势B细胞抗原表位。重组载体p-S(A-D)-His和p-N-His均在PK-15细胞内成功表达,且S(A-D)-His和N-His在PK-15细胞核和细胞质中均有分布。重组疫苗载体免疫小鼠后,免疫效果由高至低依次为p-N-His>p-S(A-D)-His + p-N-His>p-S(A-D)-His。结论 本研究构建了TGEV的 S、N基因的DNA疫苗载体,免疫小鼠后均产生了较强的特异性抗体,为TGEV的核酸疫苗的研制提供了基础材料和依据。 Abstract:Objective DNA vaccine vector of S and N genes of porcine transmissible gastroenteritis virus (TGEV) was constructed with the vaccine immunogenicity detemined to pave the way for studying, preventing, and controling TGE. Method A and D sites on S and N from a TGEV were amplified. The N gene alone as well as the A and D sites fusion were cloned into the vaccine vector pCDNA3.1-His-C. Bioinformatics software was used to predict and analyze the secondary structure, tertiary configuration, subcellular localization, and dominant B cell epitope of S (A-D) and N proteins. The recombinant vectors were transfected into PK-15 cells, and expression distribution of N and the A and D sites fusion detected by indirect immunofluorescence and confocal detection. Mice were immunized with the single or combined recombinant vaccine vector to detect the IgG antibody using indirect ELISA. Result The A and D sites of the S were 498bp and 606bp, respectively, and the N, 1,149bp in length. The nucleic acid vaccine expression vectors p-S (A-D)-His and p-N-His for the A and D sites (fusion) and N were constructed. Bioinformatics software predicted that, when TGEV infected the host cells, N protein was mainly located in the nucleus and mitochondria and S (A-D) largely in the cytoplasm and mitochondria, while S (A-D) had 7 and N, 8 dominant B cell epitopes. All p-S (A-D)-His and p-N-His were successfully expressed in PK-15 cells distributed in the nucleus and cytoplasm. The immunized mice showed an effect of immunity in the order of p-N-His>p-S (A-D)-His + p-N-His>p-S (A-D)-His. Conclusion The DNA vaccine vectors of S and N of TGEV were successfully constructed. Strong specific antibodies were generated in lab mice after the immunization. -
Key words:
- TGEV /
- S and N gene /
- vector construction /
- immunogenicity
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图 2 TGEV S基因A、D位点扩增结果
A:A位点扩增结果;M为DNA分子质量标准DL2000,1为扩增的A位点。B:D位点扩增结果;M为DNA分子质量标准DL2000,1为扩增的D位点。
Figure 2. Amplified A and D sites of TGEV S gene
A: amplification results of A site; M was DNA Marker DL2000, 1 was the PCR-amplified A site. B: amplification results of D site; M was DNA Marker DL2000, 1 was the PCR-amplified D site.
图 4 S基因A位点重组载体p-S(A)-His的构建与鉴定
M:DNA分子质量标准DL2000;1、2:重组载体p-S(A)-His的单酶切;3、4:重组载体p-S(A)-His的双酶切。
Figure 4. Construction and identification of p-S (A)-His and p-S (D)-His at A and D sites of S gene
M1: DNA marker DL2000; M2: DNA marker DL10000; 1: single enzyme digestion of recombinant vector p-S (A)-His; 2: single enzyme digestion of recombinant vector p-S (D)-His; 3 and 4: double digestion of recombinant vector p-S (A)-His; 5 and 6: double digestion of recombinant vector p-S (D)-His.
图 5 重组载体p-S(A-D)-His的构建与鉴定
M:DNA分子质量标准DL2000; 1:重组载体p-S(A-D)-His的单酶切;2:重组载体p-S(A-D)-His的双酶切。
Figure 5. Construction and identification of recombinant vectors p-S (A-D)-His
M: DNA marker DL2000; 1: single enzyme digestion of recombinant vector p-S(A-D)-His; 2: double digestion of recombinant vector p-S (A-D)-His.
表 1 S基因A位点、D位点和N基因扩增引物序列
Table 1. Sequences of primers for amplifications of A and D sites and N gene
基因
Gene引物
Primers序列(5′−3′)
Sequence(5′−3′)酶切位点
Restriction enzyme cutting siteS基因A位点
A-site in S geneP1 CGCGGATCCATGTTAGTTACCAAACAGCCGT Bam H I P2 CCGGAATTCTATTGTCCAGAAAACGTCAC Eco R I S基因D位点
D-site in S geneP3 CCGGAATTCAAGTTGAAAACACAGCTATT Eco R I P4 TGCTCTAGA ACTATTATCAGACGGTACACC Xba I N基因
N GeneP5 CGCGGATCCATGGCCAACCAGGGAC Bam H I P6 CCGGAATTCGTTCGTTACCTCATCAATT Eco R I 表中加下划线的碱基序列为酶切位点序列。
Cleavage sites are underlined.表 2 小鼠分组及免疫程序
Table 2. Groups and procedures of mice immunization
组别
Group疫苗载体种类
Vaccine carrier type免疫剂量
Immunizing dose/μg小鼠数量
Number of mice免疫时间
Immune frequency免疫位置
Immune site1 p-S(A-D)-His 240 6 第1、7、21天 脚底板 2 p-N-His 240 6 第1、7、21天 脚底板 3 p-S(A-D)-His + p-N-His 120+120 6 第1、7、21天 脚底板 4 pCDNA3.1-His-C 240 6 第1、7、21天 脚底板 表 3 S(A-D)蛋白和N蛋白亚细胞定位预测
Table 3. Predicted subcellular localization of S (A-D) and N proteins
组别
Group亚细胞定位
Subcellular localization可能性
Possibility/%S(A-D)蛋白
S(A-D) protein细胞质 Cytoplasm 34.8 线粒体 Mitochondria 17.4 细胞核 Cell nucleus 13.0 质膜 Plasmalemma 13.0 内质网 Endoplasmic reticulum 8.7 N蛋白
N protein细胞核 Cell nucleus 65.2 线粒体 Mitochondria 17.4 细胞质 Cytoplasm 13.0 溶酶体 Lysosome 4.3 表 4 S(A-D)蛋白和N蛋白的B细胞抗原表位预测
Table 4. Predicted B cell epitope of S (A-D) and N proteins
蛋白
Protein序号
Number起始位点
Start site结束位点
End site序列
Amino acid sequenceS(A-D)蛋白
S(A-D)protein1 33 43 FDQCNGAVLNN 2 55 62 TTNVQSGK 3 86 101 DSSFFSYGEIPFGVTD 4 195 211 NLNNGFYPVSSSEVGLV 5 233 250 LGMKRSGYGQPIASTLSN 6 281 295 ALWDNIFKRNCTDVL 7 306 318 CPFSFDKLNNYLT N蛋白
N protein1 4 32 QGQRVSWGDESTKTRGRSNSRGRKSNNIP 2 43 87 QGSKFWNLCPRDFVPNGIGNRDQQIGYWNRQTRYRMVKGQRKELP 3 101 108 ADAKFKDK 4 118 146 DGAMNKPTTLGSRGANNESKALKFDGKVP 5 150 189 QLEVNQSRDNSRSRSQSRSRSRNRSQSRGRQQSNNKKDDS 6 201 244 LGVDTEKQQQRSRSKSKERSNSKTRDTTPKNENKHTWKRTAGKG 7 251 271 GARSSSANFGDSDLVANGSSA 8 316 378 DPKTEQFLQQINAYARPSEVAKEQRKRKSRSKSAERSEQEVVPDALIENYTDVFDDTQVEIID 表 5 免疫小鼠抗TGEV血清IgG间接ELISA检测
Table 5. Anti-TGEV serum IgG in immunized mice detected by indirect ELISA
组别
Group疫苗载体种类
Vaccine carrier type免疫后不同时间抗TGEV血清IgG水平(OD450 nm)
Anti-TGEV serum IgG levels at different time after immunization (OD450 nm)0天
0 days14天
14 days28天
28 days42天
42 days1 p-S(A-D)-His 0.133±0.011 a 0.218± 0.0075 b0.243± 0.0060 c0.401± 0.0100 c2 p-N-His 0.138±0.016 a 0.244± 0.0025 a0.344± 0.0070 a0.504± 0.0141 a3 p-S(A-D)-His + p-N-His 0.142± 0.0050 a0.225± 0.0021 b0.300± 0.0050 b0.471± 0.0075 b4 pCDNA3.1-His-C 0.134± 0.0089 a0.144± 0.0076 c0.141± 0.0069 c0.139± 0.0020 d同列数据肩标小写字母完全不同表示差异显著(P<0.05),含相同小写字母或无肩标表示差异不显著(P>0.05)。
Data with different lowercase letters on same column indicate significant differences at P<0.05; those with or without same lowercase letters indicate no significant differences at P>0.05. -
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