[目的]利用生物信息学方法预测绿脓杆菌外膜蛋白OprF的理化性质、高级结构和细胞表位。[方法]采用在线软件预测OprF蛋白的理化性质;Signal P 4.1软件预测OprF信号肽序列;利用TMHMM软件预测ACFA蛋白跨膜结构;SOPMA服务器预测蛋白的二级结...[目的]利用生物信息学方法预测绿脓杆菌外膜蛋白OprF的理化性质、高级结构和细胞表位。[方法]采用在线软件预测OprF蛋白的理化性质;Signal P 4.1软件预测OprF信号肽序列;利用TMHMM软件预测ACFA蛋白跨膜结构;SOPMA服务器预测蛋白的二级结构;Swiss-Model程序预测OprF三维结构;综合ABCpred与Bepi Pred方案预测OprF的B细胞表位;运用神经网络法预测OprF的CTL表位;使用MHC-Ⅱ类分子结合肽程序预测OprF的Th细胞表位。[结果]OprF为亲水性蛋白;1~24位氨基酸为信号肽序列;存在多个酶切位点;无跨膜结构并定位于细胞膜外;二级结构中含无规则卷曲34.36%、α-螺旋31.90%、β-转角11.66%、β-片层22.09%;并可能存在3个B细胞表位、2个CTL表位、4个Th细胞表位。[结论]系统分析了OprF蛋白的理化性质、信号肽、跨膜结构、二级与三级结构,以及B、T细胞抗原表位。展开更多
对溶藻弧菌外膜蛋白OmpU进行分子克隆构建,抗原性生物信息学分析,为疫苗的开发奠定了基础。通过分子克隆获得OmpU蛋白的原核表达菌株,重组表达后利用切胶纯化获得OmpU蛋白,免疫小鼠制备抗血清,Western Blotting检测发现OmpU蛋白具有很...对溶藻弧菌外膜蛋白OmpU进行分子克隆构建,抗原性生物信息学分析,为疫苗的开发奠定了基础。通过分子克隆获得OmpU蛋白的原核表达菌株,重组表达后利用切胶纯化获得OmpU蛋白,免疫小鼠制备抗血清,Western Blotting检测发现OmpU蛋白具有很好的抗原性。采用在线软件预测OmpU为亲水的分泌型蛋白;存在多个酶切位点。采用TMHMM Server v.2.0程序预测OmpU无跨膜结构并定位于细胞膜外。通过Signal P 4.1软件分析发现OmpU的1~21位氨基酸为信号肽序列。SOPMA服务器预测OmpU的二级结构含无规则卷曲27.94%,α-螺旋为33.24%,β-转角为10.29%,β-片层为28.53%。采用Swiss Model程序预测三维结构显示OmpU具有3个孔道结构。综合利用ABCpred和Bepi Pred方案,预测OmpU存在8个B细胞表位。运用神经网络法预测OmpU具有3个CTL表位。使用MHC-Ⅱ类分子结合肽在线程序预测OmpU存在1个Th表位。展开更多
Antibodies against the toxin portion of recombinant immunotoxins （RIT） reduce their efficacy and pose a potential safety risk. To overcome this problem we mutated the very immunogenic immunotoxin SSIP to produce LMB...Antibodies against the toxin portion of recombinant immunotoxins （RIT） reduce their efficacy and pose a potential safety risk. To overcome this problem we mutated the very immunogenic immunotoxin SSIP to produce LMB-T20, a de-immunized RIT that has the eight human T-cell epitopes in SSIP modified or removed. To determine the effect of T-cell epitope removal in vivo we mapped the T-cell epitopes in immune-competent BALB/c mice and found that these mice recognize two epitopes. One corresponds to the human immunodominant T-cell epitope and the other to a human subdominant epitope; both were eliminated in LMB-T20. We found that mice immunized with LMB-T20 did not have T-cell activation and did not develop anti-drug antibodies （ADA）, whereas mice immunized with SSIP, showed T-cell activation, and developed ADA detected by both ELISA and drug neutralizing assays. The ability of the mice treated with LMB-T20 to respond to other antigens was not compromised. We conclude that elimination of T-cell epitopes is sufficient to prevent formation of antibodies to an immunogenic foreign protein.展开更多
The in silico prediction of peptide binding affinities to MHC proteins is a very important first step in the process of epi-tope-based vaccine design and development. Five MHC class II binding prediction servers were ...The in silico prediction of peptide binding affinities to MHC proteins is a very important first step in the process of epi-tope-based vaccine design and development. Five MHC class II binding prediction servers were combined in different ways and the resulting performance of these combinations was evaluated using a test set, which consisted of 4540 known HLA-DRB1 binders. The five servers were: NetMHCIIpan, NetMHCII, ProPred, RANKPEP, and EpiTOP. The top 5% of the ranked predictions from each server were combined using union and intersection operators. The outputs were evaluated in terms of sensitivity and positive predictive value (PPV). The union operator showed high sensitivity (65-79%) and low PPVs (6-8%), while intersection outputs had low sensitivities (4-41%) yet significantly higher PPVs (14-31%). Thus there is a defining trade-off between sensitivity and PPV for each combination. The union of outputs from different servers brings more “noise” than “signal” to the resulting set of predicted binders. Conversely, selecting only commonly predicted binders increases the probability that an identified binder is a true binder.展开更多
The current study was designed to examine the protective efficacy of DNA vaccines based on gp63 and Hsp70 against murine visceral leishmaniasis. Inbred BALB/c mice were immunized subcutaneously twice at an interval of...The current study was designed to examine the protective efficacy of DNA vaccines based on gp63 and Hsp70 against murine visceral leishmaniasis. Inbred BALB/c mice were immunized subcutaneously twice at an interval of three weeks with pcDNA3.1 （＋） encoding T cell epitopes of gp63 and Hsp70 individually and in combination. Animals were challenged intracardially with 107 promastigotes ofLeishmania donovani 10 days post immunization and sacrificed 1,2 and 3 months post challenge. The immunized animals revealed a significant reduction （P 〈 0.05） in splenic and hepatic parasite burden as compared to the infected controls. Maximum reduction in parasite load （P 〈 0.05） was observed in animals treated with a combination ofpcDNA/gp63 and pcDNA/Hsp70. These animals also showed heightened DTH response, increased IgG2a, elevated Thl cytokines （IFN-γ and IL-2） and reduced IgG 1 and IL-10 levels. Thus, mice immunized with the cocktail vaccine exhibited significantly greater protection in comparison to those immunized with individual antigens.展开更多
文摘[目的]利用生物信息学方法预测绿脓杆菌外膜蛋白OprF的理化性质、高级结构和细胞表位。[方法]采用在线软件预测OprF蛋白的理化性质;Signal P 4.1软件预测OprF信号肽序列;利用TMHMM软件预测ACFA蛋白跨膜结构;SOPMA服务器预测蛋白的二级结构;Swiss-Model程序预测OprF三维结构;综合ABCpred与Bepi Pred方案预测OprF的B细胞表位;运用神经网络法预测OprF的CTL表位;使用MHC-Ⅱ类分子结合肽程序预测OprF的Th细胞表位。[结果]OprF为亲水性蛋白;1~24位氨基酸为信号肽序列;存在多个酶切位点;无跨膜结构并定位于细胞膜外;二级结构中含无规则卷曲34.36%、α-螺旋31.90%、β-转角11.66%、β-片层22.09%;并可能存在3个B细胞表位、2个CTL表位、4个Th细胞表位。[结论]系统分析了OprF蛋白的理化性质、信号肽、跨膜结构、二级与三级结构,以及B、T细胞抗原表位。
文摘对溶藻弧菌外膜蛋白OmpU进行分子克隆构建,抗原性生物信息学分析,为疫苗的开发奠定了基础。通过分子克隆获得OmpU蛋白的原核表达菌株,重组表达后利用切胶纯化获得OmpU蛋白,免疫小鼠制备抗血清,Western Blotting检测发现OmpU蛋白具有很好的抗原性。采用在线软件预测OmpU为亲水的分泌型蛋白;存在多个酶切位点。采用TMHMM Server v.2.0程序预测OmpU无跨膜结构并定位于细胞膜外。通过Signal P 4.1软件分析发现OmpU的1~21位氨基酸为信号肽序列。SOPMA服务器预测OmpU的二级结构含无规则卷曲27.94%,α-螺旋为33.24%,β-转角为10.29%,β-片层为28.53%。采用Swiss Model程序预测三维结构显示OmpU具有3个孔道结构。综合利用ABCpred和Bepi Pred方案,预测OmpU存在8个B细胞表位。运用神经网络法预测OmpU具有3个CTL表位。使用MHC-Ⅱ类分子结合肽在线程序预测OmpU存在1个Th表位。
文摘Antibodies against the toxin portion of recombinant immunotoxins （RIT） reduce their efficacy and pose a potential safety risk. To overcome this problem we mutated the very immunogenic immunotoxin SSIP to produce LMB-T20, a de-immunized RIT that has the eight human T-cell epitopes in SSIP modified or removed. To determine the effect of T-cell epitope removal in vivo we mapped the T-cell epitopes in immune-competent BALB/c mice and found that these mice recognize two epitopes. One corresponds to the human immunodominant T-cell epitope and the other to a human subdominant epitope; both were eliminated in LMB-T20. We found that mice immunized with LMB-T20 did not have T-cell activation and did not develop anti-drug antibodies （ADA）, whereas mice immunized with SSIP, showed T-cell activation, and developed ADA detected by both ELISA and drug neutralizing assays. The ability of the mice treated with LMB-T20 to respond to other antigens was not compromised. We conclude that elimination of T-cell epitopes is sufficient to prevent formation of antibodies to an immunogenic foreign protein.
文摘The in silico prediction of peptide binding affinities to MHC proteins is a very important first step in the process of epi-tope-based vaccine design and development. Five MHC class II binding prediction servers were combined in different ways and the resulting performance of these combinations was evaluated using a test set, which consisted of 4540 known HLA-DRB1 binders. The five servers were: NetMHCIIpan, NetMHCII, ProPred, RANKPEP, and EpiTOP. The top 5% of the ranked predictions from each server were combined using union and intersection operators. The outputs were evaluated in terms of sensitivity and positive predictive value (PPV). The union operator showed high sensitivity (65-79%) and low PPVs (6-8%), while intersection outputs had low sensitivities (4-41%) yet significantly higher PPVs (14-31%). Thus there is a defining trade-off between sensitivity and PPV for each combination. The union of outputs from different servers brings more “noise” than “signal” to the resulting set of predicted binders. Conversely, selecting only commonly predicted binders increases the probability that an identified binder is a true binder.
基金support provided by the Indian Council of Medical ResearchDepartment of Health Research,India for providing financial support for this study under project ref.5/8-7(77)/2006-ECD-||
文摘The current study was designed to examine the protective efficacy of DNA vaccines based on gp63 and Hsp70 against murine visceral leishmaniasis. Inbred BALB/c mice were immunized subcutaneously twice at an interval of three weeks with pcDNA3.1 （＋） encoding T cell epitopes of gp63 and Hsp70 individually and in combination. Animals were challenged intracardially with 107 promastigotes ofLeishmania donovani 10 days post immunization and sacrificed 1,2 and 3 months post challenge. The immunized animals revealed a significant reduction （P 〈 0.05） in splenic and hepatic parasite burden as compared to the infected controls. Maximum reduction in parasite load （P 〈 0.05） was observed in animals treated with a combination ofpcDNA/gp63 and pcDNA/Hsp70. These animals also showed heightened DTH response, increased IgG2a, elevated Thl cytokines （IFN-γ and IL-2） and reduced IgG 1 and IL-10 levels. Thus, mice immunized with the cocktail vaccine exhibited significantly greater protection in comparison to those immunized with individual antigens.
