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1.
A cDNA encoding the simian-human immunodeficiency virus (SHIV 89.6p) Tat regulatory element protein was fused to the c-terminus of the cholera toxin B subunit gene (ctxB-tat) and introduced into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation methods. The fusion gene was detected in the genomic DNA of transformed potato leaf cells by PCR DNA amplification. Synthesis and assembly of the CTB-Tat fusion protein into oligomeric structures of pentamer size was detected in transformed tuber extracts by immunoblot analysis. The binding of CTB-Tat fusion protein pentamers to intestinal epithelial cell membrane glycolipid receptors was quantified by G(M1)-ganglioside enzyme-linked immunosorbent assay (G(M1)-ELISA). Based on the ELISA results, CTB-Tat fusion protein made up about 0.005-0.007% of total soluble tuber protein or approximately 4.6mg per 100g potato tuber tissue. The synthesis and assembly of CTB-Tat monomers into biologically active oligomers in transformed potato tuber tissues demonstrates the feasibility of using viral pathogen antigens synthesized in edible plants for mucosal immunization against HIV-1 infection.  相似文献   

2.
A DNA encoding the 27-kDa domain I of anthrax lethal factor protein (LF), was linked to the carboxyl terminus of the cholera toxin B-subunit (CTB-LF). The CTB-LF fusion gene was transferred into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated in vivo transformation methods and antibiotic-resistant plants were regenerated. The CTB-LF fusion gene was detected in transformed potato leaf genomic DNA by polymerase chain reaction (PCR)-mediated DNA amplification. Immunoblot analysis with anti-CTB and anti-LF primary antibodies verified the synthesis and assembly of biologically active CTB-LF fusion protein oligomers in transformed plant tuber tissues. Furthermore, the binding of CTB-LF fusion protein pentamers to intestinal epithelial cell membrane receptors measured by GM1-ganglioside enzyme-linked immunosorbent assay (GM1-ELISA) indicated that the CTB-LF fusion protein made up approx 0.002% of the total soluble tuber protein. Synthesis of CTB-LF monomers and their assembly into biologically active CTB-LF fusion protein pentamers in potato tuber tissues demonstrates the feasibility of using edible plants for production and delivery of adjuvanted LF protein for CTB-mediated immunostimulation of mucosal immune responses against anthrax toxin.  相似文献   

3.
A gene encoding VP7, the outer capsid protein of simian rotavirus SA11, was fused to the carboxyl terminus of the cholera toxin B subunit gene. A plant expression vector containing the fusion gene under control of the mannopine synthase P2 promoter was introduced into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation. The CTB::VP7 fusion gene was detected in the genomic DNA of transformed potato leaf cells by polymerase chain reaction (PCR) amplification methods. Immunoblot analysis of transformed potato tuber tissue extracts showed that synthesis and assembly of the CTB::VP7 fusion protein into oligomers of pentameric size occurred in the transformed plant cells. The binding of CTB::VP7 fusion protein pentamers to sialo-sugar containing GM1 ganglioside receptors on the intestinal epithelial cell membrane was quantified by enzyme-linked immunosorbent assay (ELISA). The ELISA results showed that the CTB::VP7 fusion protein made up approx 0.01% of the total soluble tuber protein. Synthesis and assembly of CTB::VP7 monomers into biologically active pentamers in transformed potato tubers demonstrates the feasibility of using edible plants as a mucosal vaccine for the production and delivery system for rotavirus capsid protein antigens.  相似文献   

4.
A deoxyribonucleic acid (DNA) fragment encoding the cholera toxin B subunit (CTB) was linked 5′ to the simian immunodeficiency virus (SIVmac) Gag p27 capsid gene (CTB-Gag). The fusion gene was transferred into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation methods and transformed plants regenerated. The CTB-Gag gene fusion was detected in transformed potato leaf genomic DNA by polymerase chain reaction-mediated DNA amplification. The results of immunoblot analysis with anti-CTB and anti-Gag antibodies verified the synthesis of biologically active CTB-Gag fusion protein in transformed leaf and tuber tissues. Synthesis and assembly of the CTB-Gag fusion protein into oligomeric structures of pentamer size was confirmed by GM1-ganglioside-enzyme-linked immunosorbent assay (GM1-ELISA) of transformed potato tuber tissue extracts. The binding of CTB-Gag fusion protein oligomers to intestinal epithelial cell membrane receptors quantified by GM1-ELISA showed that CTB-Gag fusion protein made up approx 0.016–0.022% of the total soluble tuber protein. The synthesis of CTB-Gag monomers and their assembly into biologically active CTB-Gag fusion protein oligomers in potato tuber tissues provides the opportunity for employment of the carrier and adjuvant properties of CTB for the development of edible plant-based subunit mucosal vaccines for enhanced mucosal immunity against SIV in macaques.  相似文献   

5.
A CTB-NSP4(175) fusion gene encoding the entire 175-aa murine rotavirus NSP4 enterotoxin protein was transferred into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation. The CTB-NSP4(175) enterotoxin fusion gene was detected in the genomic DNA of transformed leaves by PCR DNA amplification. Synthesis and assembly of the full-length CTB-NSP4(175) fusion protein into oligomeric structures of pentamer size was detected in transformed tuber extracts by immunoblot analysis. The binding of CTB-NSP4(175 )fusion protein pentamers to intestinal epithelial cell membrane receptors was quantified by G(M1)-ganglioside enzyme-linked immunosorbent assay (G(M1)-ELISA). The ELISA results showed that CTB-NSP4(175) fusion protein was 0.006-0.026% of the total soluble tuber protein. The synthesis of CTB-NSP4(175) monomers and their assembly into biologically active oligomers in transformed potato tubers demonstrates the feasibility of using edible plants for the synthesis of enterocyte-targeted full-length rotavirus enterotoxin antigens that retain all of their pathogenic epitopes for initiation of a maximum mucosal immune response.  相似文献   

6.
The gram-negative anaerobic oral bacterium Porphyromonas gingivalis initiates periodontal disease by binding to saliva-coated oral surfaces. To assess whether edible plants can synthesize biologically active P. gingivalis fimbrial antigen, for application as an oral vaccine, a cDNA fragment encoding the C-terminal binding portion of P. gingivalis fimbrial protein (FimA), was cloned into a plant expression vector immediately downstream of a cDNA fragment encoding the cholera toxin B subunit (CTB). The chimeric plasmid was transferred into potato (Solanum tuberosum) cells and the ctb-fimA cDNA fragment detected in transformed leaf genomic DNA by PCR amplification methods. A novel protein band of 21 kDa was detected in transformed potato tuber extracts by immunoblot analysis. Oligomeric CTB-FimA (266-337) fusion protein was identified in the extracts through the binding of anti-CTX and anti-native fimbriae antibodies. The pentameric structure of CTB-FimA fusion protein was confirmed by ELISA measurements of GM1 ganglioside receptor binding. Quantification of the CTB-FimA fusion protein by ELISA indicated that the chimeric protein made up about 0.33% of total soluble tuber protein. The biosynthesis of immunologically detectable CTB-FimA fusion proteins and the assembly of fusion protein monomers into biologically active pentamers in transformed potato tuber tissues demonstrate the feasibility of synthesizing adjuvanted fimbrial protein in edible plants for development of adjuvanted mucosal vaccines against P. gingivalis generated periodontal disease.  相似文献   

7.
SIVmac Gag p27 capsid protein gene expression in potato   总被引:3,自引:0,他引:3  
A cDNA encoding the Simian immunodeficiency virus type (SIV(mac)) Gag capsid protein was introduced into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation methods. The gag gene was detected in the genomic DNA of transformed leaf tissues by PCR DNA amplification. Immunoblot analysis of transformed potato plant extracts with anti-Gag monoclonal antibody showed that biologically active Gag protein was synthesized in transformed tuber tissues. Based on ELISA results, recombinant Gag protein made up 0.006-0.014% of total soluble tuber protein. The synthesis of SIV Gag in transformed potato tubers opens the way for development of Gag-based edible plant vaccines for protection against SIV and potentially HIV-1 infection.  相似文献   

8.
A gene encoding the outer capsid glycoprotein (VP7) of simian rotavirus SA11, was genetically linked to the amino terminus of the ricin toxin B subunit (RTB) isolated from castor-oil plant (Ricinus communis) seeds. To assess fusion protein expression in plant cells, the VP7::RTB fussion gene was transferred into potato (Solanum tuberosum) cells by Agrobacterium tumefaciens-mediated transformation methods and transformed plants regenerated. The fusion gene was detected in transformed potato genomic DNA by polymerase chain reaction DNA amplification methods. Immunoblot analysis with anti-SA11 antiserum as the primary antibody verified the presence of VP7::RTB fusion protein in transformed potato tuber tissues. The plant-synthesized fusion protein bound RTB membrane receptors as measured by asialofetuin-enzyme-linked immunosorbent assay (ELISA). The ELISA results indicated that the VP7::RTB fusion protein was biologically active and made up approx 0.03% of total soluble transformed tuber protein. The biosynthesis of receptor binding VP7::RTB fusion protein in potato tissues demonstrates the feasibility of producing monomeric ricin toxin B subunit adjuvant-virus antigen fusion proteins in crop plants for enhanced immunity.  相似文献   

9.
目的构建含有HIV-1C亚型gp120基因重组腺病毒载体,并在293细胞中表达gp120蛋白。方法PCR扩增,获得HIV-1C亚型gp120片段,定向克隆人腺病毒转移载体pTrack-CMV,线性化后转化至含有腺病毒骨架载体pAd-easy-1的大肠埃希菌BJ5183,获得重组子prAd—gp120,PacI酶切纯化后转染293细胞,包装成复制缺陷型重组腺病毒vAd—gp120。结果经PCR、酶切及DNA测序,插入片段大小、方向正确,获得了具有感染力的vAd—gp120重组腺病毒;通过Western印迹检测,重组腺病毒在293细胞中表达出分子量为120kD的蛋白。结论成功构建了含有HIV-1C亚型gp120基因重组腺病毒载体,并获得该基因的表达。  相似文献   

10.
Expression of cholera toxin B subunit oligomers in transgenic potato plants   总被引:36,自引:0,他引:36  
A gene encoding the cholera toxin B subunit protein (CTB), fused to an endoplasmic reticulum (ER) retention signal (SEKDEL) was inserted adjacent to the bi-directional mannopine synthase P2 promoter in a plant expression vector containing a bacterial luciferase AB fusion gene (luxF) linked to the P1 promoter. Potato leaf explants were transformed by Agrobacterium tumefaciens carrying the vector and kanamycin-resistant plants were regenerated. The CTB-SEKDEL fusion gene was identified in the genomic DNA of bioluminescent plants by polymerase chain reaction amplification. Immunoblot analysis indicated that plant-derived CTB protein was antigenically indistinguishable from bacterial CTB protein, and that oligomeric CTB molecules (Mr 50 kDa) were the dominant molecular species isolated from transgenic potato leaf and tuber tissues. Similar to bacterial CTB, plant-synthesized CTB dissociated into monomers (Mr 15 kDa) during heat or acid treatment. The maximum amount of CTB protein detected in auxin-induced transgenic potato leaf and tuber tissues was approximately 0.3% of total soluble plant protein. Enzyme-linked immunosorbent assay methods indicated that plant-synthesized CTB protein bound specifically to GM1-ganglioside, the natural membrane receptor of cholera toxin. In the presence of the SEKDEL signal, CTB protein accumulates in potato tissues and is assembled into an oligomeric form that retains native biochemical and immunological properties. The expression of oligomeric CTB protein with immunological and biochemical properties identical to native CTB protein in edible plants opens the way for preparation of inexpensive food plant-based oral vaccines for protection against cholera and other pathogens in endemic areas throughout the world  相似文献   

11.
Periodontal disease caused by the gram-negative oral anaerobic bacterium Porphyromonas gingivalis is thought to be initiated by the binding of P. gingivalis fimbrial protein to saliva-coated oral surfaces. To assess whether biologically active fimbrial antigen can be synthesized in edible plants, a cDNA fragment encoding the C-terminal binding portion of P. gingivalis fimbrial protein, fimA (amino acids 266–337), was cloned behind the mannopine synthase promoter in plant expression vector pPCV701. The plasmid was transferred into potato (Solanum tuberosum) leaf cells by Agrobacterium tumefaciens in vivo transformation methods. The fimA cDNA fragment was detected in transformed potato leaf genomic DNA by PCR amplification methods. Further, a novel immunoreactive protein band of ~6.5 kDa was detected in boiled transformed potato tuber extracts by acrylamide gel electrophoresis and immunoblot analysis methods using primary antibodies to fimbrillin, a monomeric P. gingivalis fimbrial subunit. Antibodies generated against native P. gingivalis fimbriae detected a dimeric form of bacterial-synthesized recombinant FimA(266–337) protein. Further, a protein band of ~160 kDa was recognized by anti-FimA antibodies in undenatured transformed tuber extracts, suggesting that oligomeric assembly of plant-synthesized FimA may occur in transformed plant cells. Based on immunoblot analysis, the maximum amount of FimA protein synthesized in transformed potato tuber tissues was approximately 0.03% of total soluble tuber protein. Biosynthesis of immunologically detectable FimA protein and assembly of fimbrial antigen subunits into oligomers in transformed potato tuber tissues demonstrate the feasibility of producing native FimA protein in edible plant cells for construction of plant-based oral subunit vaccines against periodontal disease caused by P. gingivalis.  相似文献   

12.
Glycosphingolipids from human erythrocytes mediate CD4-dependent fusion with cells expressing human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins. To identify the glycosphingolipid(s) which participates in the fusion process, we have analyzed the interaction of HIV-1 gp120 (X4 and R5X4 isolates) with reconstituted membrane microdomains of human erythrocyte glycosphingolipids. We identified globotriaosylceramide (Gb3) and ganglioside GM3 as the main glycosphingolipids recognized by gp120. In the presence of CD4, Gb3 interacted preferentially with the X4 gp120, whereas GM3 interacted exclusively with the R5X4 gp120. These data suggest that glycosphingolipid microdomains are required in CD4-dependent fusion and that Gb3 and/or GM3 may function as alternative entry cofactors for selected HIV-1 isolates.  相似文献   

13.
A random mutagenesis library of gp120-801 (a large segment of the envelope protein gene of HIV-1) was constructed using error-prone PCR and DNA shuffling methods, and one mutant of gp120-801 was selected from this library using a green fluorescent protein (GFP) fusion vector. After being cloned into pEX31b and expressed in E. coli, the expressed fusion protein reached to 15% of total bacterial proteins for the mutant but was just 1–2% for the wild type.  相似文献   

14.
To study the intracellular transport and biological properties of the human immunodeficiency virus type 1 (HIV-1) transmembrane glycoprotein (TM; gp41), we constructed a truncated envelope gene in which the majority of the coding sequences for the surface glycoprotein (SU; gp120) were deleted. Transient expression of this truncated env gene in primate cells resulted in the biosynthesis of two proteins with M(r)s of 52,000 and 41,000, respectively. Immunofluorescence studies with antibodies to the HIV-1 TM protein indicated that the intracellular and surface localization of these proteins were indistinguishable from those of the native HIV-1 gp120-gp41 complex. These results indicate that the oligosaccharide processing and cell surface transport of the HIV-1 TM protein were not dependent on the presence of the receptor binding subunit, gp120. Syncytium formation was readily detected upon expression of the deleted HIV-1 env gene into COS and CD4+ HeLa cell lines, suggesting that in the absence of gp120, the TM protein retained biological activity. This observation was confirmed by infection of primate and mouse cell lines with a recombinant vaccinia virus (vvgp41) expressing the truncated HIV-1 env gene. These results strongly suggest that (i) the two biological activities of the HIV-1 envelope glycoprotein can occur independently and (ii) the association of the two glycoprotein subunits may restrict the fusion activity of the transmembrane component to CD4+ cells.  相似文献   

15.
To construct the eukaryotic expression vector of HIV-1 gp120 gene and observe its expression in vitro, the recombinant expression vector pVAX1GP120 was constructed by inserting the gp120 gene into the eukaryotic expression vector pVAX1. The pVAX1GP120 was transfected into Vero cells by lipofectamine and the expressed product was detected by indirect immunofluore- scence.Restriction enzymes digestion analysis and sequencing results revealed that the recombinant expression vector pVAX1GP120 has been constructed successfully. The indirect immunofluorescence result showed green fluorescence on the membrane of transfected cells. The constructed eukaryotic expression vector of HIV-1 gp120 can be expressed in vitro, which lay the foundation for the further study of HIV-1 DNA vaccine.  相似文献   

16.
The Gag protein of human immunodeficiency virus type 1 (HIV-1) associates with the envelope protein complex during virus assembly. The available evidence indicates that this interaction involves recognition of the gp41 cytoplasmic tail (CT) by the matrix protein (MA) region of Pr55(Gag). Here we show that substitution of Asp for Leu at position 49 (L49D) in MA results in a specific reduction in particle-associated gp120 without affecting the levels of gp41. Mutant virions were markedly reduced in single-cycle infectivity despite a relatively modest defect in fusion with target cells. Studies with HIV-1 particles containing decreased levels of envelope proteins suggested that the L49D mutation also inhibits a postentry step in infection. Truncation of the gp41 tail, or pseudotyping by vesicular stomatitis virus glycoprotein, restored both the fusion and infectivity of L49D mutant virions to wild-type levels. Truncation of gp41 also resulted in equivalent levels of gp120 on particles with and without the MA mutation and enhanced the replication of the L49D mutant virus in T cells. The impaired fusion and infectivity of L49D mutant particles were also complemented by a single point mutation in the gp41 CT that disrupted the tyrosine-containing endocytic motif. Our results suggest that an altered interaction between the MA domain of Gag and the gp41 cytoplasmic tail leads to dissociation of gp120 from gp41 during HIV-1 particle assembly, thus resulting in impaired fusion and infectivity.  相似文献   

17.
A DNA fragment encoding a 12-amino acid (aa) HIV-1 Tat transduction peptide fused to a 90-aa murine rotavirus NSP4 enterotoxin protein (Tat-NSP490) was transferred to Solanum tuberosum by Agrobacterium tumefaciens-mediated transformation. The fusion gene was detected in the genomic DNA of transformed plant leaf tissues by PCR DNA amplification. The Tat-NSP490 fusion protein was identified in transformed tuber extracts by immunoblot analysis using anti-NSP490 and anti-Tat as the primary antibodies. Enzyme-linked immunosorbent assay results showed that the Tat-NSP490 fusion protein made up to 0.0015% of the total soluble tuber protein. The synthesis of Tat-NSP490 fusion protein in transformed potato tuber tissues demonstrates the feasibility of plant cell delivery of the HIV-1 Tat transduction domain as a carrier for non-specific targeting of fused antigens to the mucosal immune system.Abbreviations APC Antigen-presenting cells - BA Benzyladenine - BSA Bovine serum albumin - CT Cholera toxin - CTB Cholera toxin B subunit - CTL Cytotoxic T lymphocytes - 2,4-D 2,4-Dichlorophenoxyacetic acid - ELISA Enzyme-linked immunosorbent assay - HIV-1 Human immunodeficiency virus type 1 - MHC Major histocompatibility complex - IAA Indole-3-acetic acid - NAA -Naphthaleneacetic acid - NPT II Neomycin phosphotransferase II - NSP4 Rotavirus enterotoxin non-structural protein - PBS Phosphate-buffered saline - PBST Phosphate-buffered saline containing 0.05% Tween-20 - PTD Protein transduction domain Communicated by W.A. Parrott  相似文献   

18.
The HIV-1 envelope glycoproteins are assembled by the trimeric gp120s and gp41s proteins. The gp120 binds sequentially to CD4 and coreceptor for initiating virus entry. Because of noncovalent interaction and heavy glycosylation for envelope glycoproteins, it is highly difficult to determine entire envelope glycoproteins structure now. Such question extremely limits our good understanding of HIV-1 membrane fusion mechanism. Here, a novel and reasonable assembly model of trimeric gp120s and gp41s was proposed based on the conformational dynamics of trimeric gp120-gp41 complex and gp41, respectively. As for gp41, the heptad repeat sequences in the gp41 C-terminal is of enormous flexibility. On the contrary, the heptad repeat sequences in the gp41 N-terminal likely present stable three-helical bundle due to strong nonpolar interaction, and they were predicted to associate three alpha1 helixes from the non-neutralizing face of the gp120 inner domain, which is quite similar to gp41 fusion core structure. Such interaction likely leads to the formation of noncovalent gp120-gp41 complex. In the proposed assembly of trimeric gp120-gp41 complex, three gp120s present not only perfectly complementary and symmetrical distribution around the gp41, but also different flexibility degree in the different structural domains. Thus, the new model can well explain numerous experimental phenomena, present plenty of structural information, elucidate effectively HIV-1 membrane fusion mechanism, and direct to further develop vaccine and novel fusion inhibitors.  相似文献   

19.
Host cell-mediated proteolytic cleavage of the human immunodeficiency virus type 1 (HIV-1) gp160 precursor glycoprotein into gp120 and gp41 subunits is required to generate fusion-competent envelope glycoprotein (Env) spikes. The gp120-directed broadly neutralizing monoclonal antibodies (bNabs) isolated from HIV-infected individuals efficiently recognize fully cleaved JRFL Env spikes; however, nonneutralizing gp120-directed monoclonal antibodies isolated from infected or vaccinated subjects recognize only uncleaved JRFL spikes. Therefore, as an immunogen, cleaved spikes that selectively present desired neutralizing epitopes to B cells may elicit cross-reactive neutralizing antibodies. Accordingly, we inoculated nonhuman primates (NHPs) with plasmid DNA encoding transmembrane-anchored, cleaved JRFL Env or by electroporation (EP). Priming with DNA expressing soluble, uncleaved gp140 trimers was included as a comparative experimental group of NHPs. DNA inoculation was followed by boosts with soluble JRFL gp140 trimers, and control NHPs were inoculated with soluble JRFL protein trimers without DNA priming. In the TZM-bl assay, elicitation of neutralizing antibodies against HIV-1 tier 1 isolates was robust following the protein boost. Neutralization of tier 2 isolates was detected, but only in animals primed with plasmid DNA and boosted with trimeric protein. Using the more sensitive A3R5 assay, consistent neutralization of both clade B and C tier 2 isolates was detected from all regimens assessed in the current study, exceeding levels achieved by our previous vaccine regimens in primates. Together, these data suggest a potential advantage of B cell priming followed by a rest interval and protein boosting to present JRFL Env spikes to the immune system to better generate HIV-1 cross-clade neutralizing antibodies.  相似文献   

20.
周鹤峰  邵敏  葛正龙 《广西植物》2005,25(4):353-355,i0002
采用浸苗法将野生天麻总DNA导入马铃薯试管苗,对筛选得到的转化植株进行蛋白及药用成份的分析。结果显示:(1)在200株转化的马铃薯中有21株的紫外扫描图谱与正常对照组有显著差异,且在220nm有明显吸收峰。(2)5株经PCR扩增出野生天麻抗真菌蛋白(GAFP)基因。(3)转基因马铃薯与正常马铃薯的蛋白表达有明显差异,并且在转基因马铃薯中有一条与野生天麻抗真菌蛋白(GAFP)相同的条带。而正常马铃薯中无此条带。(4)通过薄层层析法检测出3株转基因马铃薯表达野生天麻的有效药用成份天麻素。说明采用浸苗法进行外源总DNA导入是可行的。  相似文献   

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