AIM： To study the immunological protective effect of H pylori vaccine with chitosan as an adjuvant and its mechanism. METHODS： Female BALB/c mice were randomly divided into seven groups and orally immunized respecti...AIM： To study the immunological protective effect of H pylori vaccine with chitosan as an adjuvant and its mechanism. METHODS： Female BALB/c mice were randomly divided into seven groups and orally immunized respectively with PBS, chitosan solution, chitosan particles, H pylori antigen, H pylori antigen plus cholera toxin （CT）, H pylori antigen plus chitosan solution, Hpylori antigen plus chitosan particles once a week for four weeks. Four weeks after the last immunization, the mice were challenged twice by alive Hpylori （1 × 10^9 CFU/mL） and sacrificed. Part of the gastric mucosa was embedded in paraffin, cut into sections and assayed with Giemsa staining. Part of the gastric mucosa was used to quantitatively culture Hpylori. EUSA was used to detect cytokine level in gastric mucosa and anti- Hpylori IgG1, IgG2a levels in serum. RESULTS： In the groups with chitosan as an adjuvant, immunological protection was achieved in 60% mice, which was significantly higher than in groups with H pylori antigen alone and without H pylori antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IFN and IL-12 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in the control group and the group without adjuvant （P 〈 0.05 or 0.005）. After challenge, the level of IFN and IL-12 was significantly higher in the groups with adjuvant than in the groups without adjuvant and antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IL-2 in gastric mucosa was not different among different groups. After challenge the level of IL-2 was significantly higher in the groups with adjuvant than in the control group （P 〈 0.05 or 0.001）. Before challenge, the level of IL-10 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05 or 0.01）. After challenge, the level of IL-10 was not different among different groups. Before challenge, the level of IL-4 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05）. After challenge, the level of IL-4 was significantly higher in the groups with chitosan particles as an adjuvant than in the group with CT as an adjuvant （P 〈 0.05）, and in the group with chitosan solution as an adjuvant, the level of IL-4 was significantly higher than that in control group, non-adjuvant group and the groups with CT （P 〈 0.05 or 0.001）. The ratio of anti- Hpylori IgG2a/ IgG1 in serum was significantly lower in the groups with chitosan as an adjuvant than in the groups with CT as an adjuvant or without adjuvant （P 〈 0.01）. CONCLUSION： H pylori vaccine with chitosan as an adjuvant can protect against H pylori infection and induce both Thl and Th2 type immune response.展开更多
AIM： To construct a recombinant live attenuated Salmonella typhimurium DNA vaccine encoding H pylori ureB gene and mouse IL-2 gene and to detect its immunogenicity in vitro and in vivo. METHODS： Hpylori ureB and mou...AIM： To construct a recombinant live attenuated Salmonella typhimurium DNA vaccine encoding H pylori ureB gene and mouse IL-2 gene and to detect its immunogenicity in vitro and in vivo. METHODS： Hpylori ureB and mouse IL-2 gene fragments were amplified by polymerase chain reaction （PCR） and cloned into pUCmT vector. DNA sequence of the amplified ureB and IL-2 genes was assayed, then cloned into the eukaryotic expression vector pIRES through enzyme digestion and ligation reactions resulting in pIRES-ureB and pIRES-ureB-IL-2. The recombinant plasmids were used to transform competent E. co/i DH5α, and the positive clones were screened by PCR and restriction enzyme digestion. Then, the recombinant pIRES-ureB and pIRES-ureB-IL-2 were used to transform LB5000 and the recombinant plasmids extracted from LB5000 were finally introduced into the final host SL7207. After that, recombinant strains were grown in vitro repeatedly. In order to detect the immunogenicib/of the vaccine in vitro, pIRES-ureB and pIRES-ureB-IL-2 were transfected to COS-7 cells using LipofectamineTM2000, the immunogenicity of expressed UreB and IL-2 proteins was assayed with SDS-PAGE and Western blot. C57BL/6 mice were orally immunized with 1 × 10^8 recombinant attenuated Salmonella typhimurium DNA vaccine. Four weeks after vaccination, mice were challenged with 1 × 10^7 CFU of live Hpylori SS1. Mice were sacrificed and the stomach was isolated for examination of H pylon 4 wk post-challenge. RESULTS： The 1700 base pair ureB gene fragment amplified from the genomic DNA was consistent with the sequence of H pylori ureB by sequence analysis. The amplified 510 base pair fragment was consistent with the sequence of mouse IL-2 in gene bank. It was confirmed by PCR and restriction enzyme digestion that H pylori ureB and mouse IL-2 genes were inserted into the eukaryotic expression vector pIRES. The experiments in vitro showed that stable recombinant live attenuated Salmonella typhimurium DNA vaccine carrying ureB and IL-2 genes was successfully constructed and the specific strips of UreB and IL-2 expressed by recombinant plasmids were detected through Western blot. Study in vivo showed that the positive rate of rapid urease test of the immunized group including ureB and ureB-IL-2 was 37.5% and 12.5% respectively, and was significantly lower than that （100%） in the control group （P 〈 0.01）. CONCLUSION： Recombinant attenuated Salmonella typhimurium DNA vaccine expressing UreB protein and IL-2 protein with immunogenicity can be constructed. It can protect mice against H pylori infection, which may help the development of a human-use H pylori DNA vaccine.展开更多
AIM： To construct a live attenuated Salmonella typhimurium （S. typhimurium） strain harboring the H pylori neutrophil activating protein （HP-NAP） gene as an oral recombinant DNA vaccine, and to evaluate its immuno...AIM： To construct a live attenuated Salmonella typhimurium （S. typhimurium） strain harboring the H pylori neutrophil activating protein （HP-NAP） gene as an oral recombinant DNA vaccine, and to evaluate its immunogenicity. METHODS： By genetic engineering methods, the genomic DNA of Hpylori was extracted as a template. The total length of the HP-NAP gene was amplified by polymerase chain reaction （PCR） and cloned into pBT vector for sequencing and BLAST analysis, then subcloned into a eukaryotic expression vector pIRES followed by PCR identification and restriction enzyme digestion. The identified recombinant plasmid pIRES-NAP was transfected into COS-7 cells for target fusion protein expression, and its antigenicity was detected by Western blotting. Then the recombinant plasmid was transformed into a live attenuated S. typhimurium strain SL7207 as an oral vaccine strain, and its immunogenicity was evaluated with animal experiments. RESULTS： A 435 bp product was cloned using high homology with HP-NAP gene in GenBank （more than 98%）. With identification by PCR and restriction enzyme digestion, a recomoinant eukaryotic expression plasmid pIRES-NAP containing the HP-NAP gene of H pylori was successfully constructed. The expressed target protein had a specific reaction with Hpyloril whole cell antibody and showed a single strip result detected by Western blotting. Oral immunization of mice with recombinant DNA vaccine strain SL7207 （pIRES-NAP） also induced a specific immune response. CONCLUSION： The successful construction of HP-NAP oral DNA vaccine with good immunogenicity may help to further investigate its immunoprotection effects and develop vaccine against Hpylori infection.展开更多
AIM:To construct a recombinant strain which expresses adhesin AlpA of Helicobacter pylori (H pylori) and to study the immunogenicity of adhesin AlpA. METHODS: Gene Ab, which was amplified from H pylori chromosomal DNA...AIM:To construct a recombinant strain which expresses adhesin AlpA of Helicobacter pylori (H pylori) and to study the immunogenicity of adhesin AlpA. METHODS: Gene Ab, which was amplified from H pylori chromosomal DNA by PCR technique, was sequenced and the biological information was analyzed, and inserted into the Nco I and Not I restriction fragments of the expression vector pET-22b(+) using T4 DNA ligase. The resulting plasmid pET-AlpA was transformed into competent E.coli BL21(DE3) cells using ampicillin resistance for selection. Recombinant strains were incubated in 5 mL LB with 100 μg/mL ampicillin overnight at 37 ℃. Sonication of BL21(DE3)pET-22b(+)/AlpA was analyzed by Western blot to detect AlpA immunogenicity. RESULTS: The gene encoding AlpA protein was amplified by PCR with chromosomal DNA of H pylori Sydney strain (SS1) as templates. It revealed that AlpA DNA fragment amplified by PCR had approximately 1 500 nucleotides, compatible with the previous reports. The recombinant plasmid pET-22b(+)/AB was successfully constructed. DNA sequencing showed one open reading frame with the length of 588 bp. It encoded seven conservative regions that showed good antigenicity and hydrophobicity by Parker and Welling method. Furthermore, INTERNET EXPASY, NNPREDICT and ISREC predicted that it was a porin-like structure consisting of β-pleated sheets that were embedded in the outer membrane. BLAST analyzed 836 767 protein sequences and found that the similar sequences were all belonging to H pylori OMP sequences. SDS-PAGE and scan analysis showed that the molecular weight of AB was 22.5 ku and recombinant protein amounted to 29% of the total bacterial protein, among which dissolved expression amounted to 21.9% of sonicated supernatant. The rAB purity amounted to 96% through affinity chromatography. Western blot analysis of rAB confirmed that it could be specially recognized by serum form rabbit immunized with AlpA and H pylori infected. CONCLUSION: Adhesin AlpA recombinant protein may be a potential vaccine for control and treatment of H pylori infection.展开更多
基金Supported by Natural Science Foundation of Jiangxi Province (No.30460052)Program of Jiangxi Provincial Leaders in Their Chosen Field of Learning,No. K010501
文摘AIM： To study the immunological protective effect of H pylori vaccine with chitosan as an adjuvant and its mechanism. METHODS： Female BALB/c mice were randomly divided into seven groups and orally immunized respectively with PBS, chitosan solution, chitosan particles, H pylori antigen, H pylori antigen plus cholera toxin （CT）, H pylori antigen plus chitosan solution, Hpylori antigen plus chitosan particles once a week for four weeks. Four weeks after the last immunization, the mice were challenged twice by alive Hpylori （1 × 10^9 CFU/mL） and sacrificed. Part of the gastric mucosa was embedded in paraffin, cut into sections and assayed with Giemsa staining. Part of the gastric mucosa was used to quantitatively culture Hpylori. EUSA was used to detect cytokine level in gastric mucosa and anti- Hpylori IgG1, IgG2a levels in serum. RESULTS： In the groups with chitosan as an adjuvant, immunological protection was achieved in 60% mice, which was significantly higher than in groups with H pylori antigen alone and without H pylori antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IFN and IL-12 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in the control group and the group without adjuvant （P 〈 0.05 or 0.005）. After challenge, the level of IFN and IL-12 was significantly higher in the groups with adjuvant than in the groups without adjuvant and antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IL-2 in gastric mucosa was not different among different groups. After challenge the level of IL-2 was significantly higher in the groups with adjuvant than in the control group （P 〈 0.05 or 0.001）. Before challenge, the level of IL-10 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05 or 0.01）. After challenge, the level of IL-10 was not different among different groups. Before challenge, the level of IL-4 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05）. After challenge, the level of IL-4 was significantly higher in the groups with chitosan particles as an adjuvant than in the group with CT as an adjuvant （P 〈 0.05）, and in the group with chitosan solution as an adjuvant, the level of IL-4 was significantly higher than that in control group, non-adjuvant group and the groups with CT （P 〈 0.05 or 0.001）. The ratio of anti- Hpylori IgG2a/ IgG1 in serum was significantly lower in the groups with chitosan as an adjuvant than in the groups with CT as an adjuvant or without adjuvant （P 〈 0.01）. CONCLUSION： H pylori vaccine with chitosan as an adjuvant can protect against H pylori infection and induce both Thl and Th2 type immune response.
基金the National Natural Science Foundation of China, No. 30170427
文摘AIM： To construct a recombinant live attenuated Salmonella typhimurium DNA vaccine encoding H pylori ureB gene and mouse IL-2 gene and to detect its immunogenicity in vitro and in vivo. METHODS： Hpylori ureB and mouse IL-2 gene fragments were amplified by polymerase chain reaction （PCR） and cloned into pUCmT vector. DNA sequence of the amplified ureB and IL-2 genes was assayed, then cloned into the eukaryotic expression vector pIRES through enzyme digestion and ligation reactions resulting in pIRES-ureB and pIRES-ureB-IL-2. The recombinant plasmids were used to transform competent E. co/i DH5α, and the positive clones were screened by PCR and restriction enzyme digestion. Then, the recombinant pIRES-ureB and pIRES-ureB-IL-2 were used to transform LB5000 and the recombinant plasmids extracted from LB5000 were finally introduced into the final host SL7207. After that, recombinant strains were grown in vitro repeatedly. In order to detect the immunogenicib/of the vaccine in vitro, pIRES-ureB and pIRES-ureB-IL-2 were transfected to COS-7 cells using LipofectamineTM2000, the immunogenicity of expressed UreB and IL-2 proteins was assayed with SDS-PAGE and Western blot. C57BL/6 mice were orally immunized with 1 × 10^8 recombinant attenuated Salmonella typhimurium DNA vaccine. Four weeks after vaccination, mice were challenged with 1 × 10^7 CFU of live Hpylori SS1. Mice were sacrificed and the stomach was isolated for examination of H pylon 4 wk post-challenge. RESULTS： The 1700 base pair ureB gene fragment amplified from the genomic DNA was consistent with the sequence of H pylori ureB by sequence analysis. The amplified 510 base pair fragment was consistent with the sequence of mouse IL-2 in gene bank. It was confirmed by PCR and restriction enzyme digestion that H pylori ureB and mouse IL-2 genes were inserted into the eukaryotic expression vector pIRES. The experiments in vitro showed that stable recombinant live attenuated Salmonella typhimurium DNA vaccine carrying ureB and IL-2 genes was successfully constructed and the specific strips of UreB and IL-2 expressed by recombinant plasmids were detected through Western blot. Study in vivo showed that the positive rate of rapid urease test of the immunized group including ureB and ureB-IL-2 was 37.5% and 12.5% respectively, and was significantly lower than that （100%） in the control group （P 〈 0.01）. CONCLUSION： Recombinant attenuated Salmonella typhimurium DNA vaccine expressing UreB protein and IL-2 protein with immunogenicity can be constructed. It can protect mice against H pylori infection, which may help the development of a human-use H pylori DNA vaccine.
基金Supported by the National Natural Science Foundation of China, No. 30170427
文摘AIM： To construct a live attenuated Salmonella typhimurium （S. typhimurium） strain harboring the H pylori neutrophil activating protein （HP-NAP） gene as an oral recombinant DNA vaccine, and to evaluate its immunogenicity. METHODS： By genetic engineering methods, the genomic DNA of Hpylori was extracted as a template. The total length of the HP-NAP gene was amplified by polymerase chain reaction （PCR） and cloned into pBT vector for sequencing and BLAST analysis, then subcloned into a eukaryotic expression vector pIRES followed by PCR identification and restriction enzyme digestion. The identified recombinant plasmid pIRES-NAP was transfected into COS-7 cells for target fusion protein expression, and its antigenicity was detected by Western blotting. Then the recombinant plasmid was transformed into a live attenuated S. typhimurium strain SL7207 as an oral vaccine strain, and its immunogenicity was evaluated with animal experiments. RESULTS： A 435 bp product was cloned using high homology with HP-NAP gene in GenBank （more than 98%）. With identification by PCR and restriction enzyme digestion, a recomoinant eukaryotic expression plasmid pIRES-NAP containing the HP-NAP gene of H pylori was successfully constructed. The expressed target protein had a specific reaction with Hpyloril whole cell antibody and showed a single strip result detected by Western blotting. Oral immunization of mice with recombinant DNA vaccine strain SL7207 （pIRES-NAP） also induced a specific immune response. CONCLUSION： The successful construction of HP-NAP oral DNA vaccine with good immunogenicity may help to further investigate its immunoprotection effects and develop vaccine against Hpylori infection.
基金Supported by the National Natural Science Foundation of China,No. 30270078
文摘AIM:To construct a recombinant strain which expresses adhesin AlpA of Helicobacter pylori (H pylori) and to study the immunogenicity of adhesin AlpA. METHODS: Gene Ab, which was amplified from H pylori chromosomal DNA by PCR technique, was sequenced and the biological information was analyzed, and inserted into the Nco I and Not I restriction fragments of the expression vector pET-22b(+) using T4 DNA ligase. The resulting plasmid pET-AlpA was transformed into competent E.coli BL21(DE3) cells using ampicillin resistance for selection. Recombinant strains were incubated in 5 mL LB with 100 μg/mL ampicillin overnight at 37 ℃. Sonication of BL21(DE3)pET-22b(+)/AlpA was analyzed by Western blot to detect AlpA immunogenicity. RESULTS: The gene encoding AlpA protein was amplified by PCR with chromosomal DNA of H pylori Sydney strain (SS1) as templates. It revealed that AlpA DNA fragment amplified by PCR had approximately 1 500 nucleotides, compatible with the previous reports. The recombinant plasmid pET-22b(+)/AB was successfully constructed. DNA sequencing showed one open reading frame with the length of 588 bp. It encoded seven conservative regions that showed good antigenicity and hydrophobicity by Parker and Welling method. Furthermore, INTERNET EXPASY, NNPREDICT and ISREC predicted that it was a porin-like structure consisting of β-pleated sheets that were embedded in the outer membrane. BLAST analyzed 836 767 protein sequences and found that the similar sequences were all belonging to H pylori OMP sequences. SDS-PAGE and scan analysis showed that the molecular weight of AB was 22.5 ku and recombinant protein amounted to 29% of the total bacterial protein, among which dissolved expression amounted to 21.9% of sonicated supernatant. The rAB purity amounted to 96% through affinity chromatography. Western blot analysis of rAB confirmed that it could be specially recognized by serum form rabbit immunized with AlpA and H pylori infected. CONCLUSION: Adhesin AlpA recombinant protein may be a potential vaccine for control and treatment of H pylori infection.
