Development of a vaccine against haemonchus contortus

Haemonchus contortus is an economically important nematode parasite of sheep and the occurrence worldwide of strains resistant to anthelmintic chemicals has emphasized the need to develop a vaccine against it. Here, Ed Munn describes the approach to this problem adopted in his laboratory. The principle developed should be applicable to other gastrointestinal parasites.     

2～59岁健康人群接种ACYW135群脑膜炎球菌多糖疫苗的免疫原性观察

目的评价ACYW135群脑膜炎球菌多糖疫苗在2～59岁健康人群中的免疫原性。方法 2～59岁健康人群接种者随机抽样(n=60),接种一剂四价脑膜炎球菌多糖疫苗。采集接种前和接种后1个月血清,采用体外杀菌试验(Serum bactericidal assay,SBA)检测血清中抗A、C、Y、W135群脑膜炎球菌的血清杀菌滴度。结果免疫前、后血清抗A群脑膜炎球菌的血清杀菌滴度GMTs(95%CI)分别为1241(736,2091)和7559(5520,10351)(P<0.05);抗C群脑膜炎球菌的血清杀菌滴度GMTs(95%CI)分别为4(9,21)和4787(2947,7775)(P<0.05);抗W135群脑膜炎球菌的血清杀菌滴度GMTs(95%CI)分别为16(9,28)和368(162,883)(P<0.05);抗Y群脑膜炎球菌的血清杀菌滴度GMTs(95%CI)分别为120(58,246)和1373(687,2745)(P<0.05)。免疫前和免疫后血清抗A群脑膜炎球菌的杀菌滴度≥128的比例分别为87(77.4,95.1)%和100(83.2,100)%;抗C群脑膜炎球菌的比例分别为17(8.3,28.5)%和97(88.5,99.6)%;抗W135群脑膜炎球菌的比例分别为13(5.9,24.6)%和68(55.0,79.7)%;抗Y群脑膜炎球菌的比例分别为57(43.2,69.4)%和85(73.4,92.9)%。免疫后较免疫前抗A群、C群、W135群和Y群脑膜炎球菌杀菌抗体滴度≥4倍升高的比例分别为50(27.2,72.8)%、97(88.5,99.6)%、62(43.2,73.9)%和55(41.6,67.9)%。结论虽然免疫前人群由于地方和国家免疫计划的实施已具有较高水平的抗A群脑膜炎球菌的血清杀菌滴度,但接种ACYW135群脑膜炎球菌多糖疫苗后可以使其保护水平进一步提高,并使人群对C群、W135群和Y群脑膜炎球菌的低水平杀菌抗体滴度均显著升高达到保护水平,证明ACYW135群脑膜炎球菌多糖疫苗在2～59岁健康人群中具有比较好的免疫原性。     

Immunogenicity of a chromatographically concentrated influenza vaccine

The immunogenicity of the Czechoslovak-made commercial vaccine Adinvira as well as that of the chromatographically concentrated vaccine Leningrad of Soviet origin was evaluated in an immunization project. The both vaccines were well tolerated after administration, the Soviet-made Leningrad brand featuring greater efficiency in eliciting an antibody response against influenza virus haemagglutinin.     

Immunogenicity of a novel, bivalent, plant-based oral vaccine against hepatitis B and human immunodeficiency viruses

A synthetic chimeric gene, TBI-HBS, encoding the immunogenic ENV and GAG epitopes of human immunodeficiency virus (HIV-1) and the surface protein antigen (HBsAg) of hepatitis B virus (HBV), was expressed in tomato plants. Tomato fruits containing the TBI-HBS antigen were fed to experimental mice and, on days 14 and 28 post-feeding, high levels of HIV- and HBV-specific antibodies were present in the serum and feces of the test animals. Intraperitoneal injection of a DNA vaccine directing synthesis of the same TBI-HBsAg antigen boosted the antibody response to HIV in the blood serum; however, it had no effect on the high level of antibodies produced to HBV.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Development of a genetically engineered vaccine against poultry coccidiosis

Coccidiosis is caused by infection with Eimeria spp. The disease is responsible for major economic loss to the poultry industry unless infections are controlled by anticoccidial drugs. John Ellis and Fiona Tomley discuss recent research on the characterization and cloning of antigens from Eimeria spp and advances towards the development of genetically engineered vaccines against poultry coccidiosis.     

Development of a mimotope-based vaccine against CD20 antigen

CD20, a B-cell-specific protein, is a primary target for immunotherapy of B-cell lymphomas. We used a mimotopes of CD20 to construct vaccines for B-cell-related disorders. The immunogenicity of the vaccines was tested in BALB/c mice. Results of this study suggest that the mimotope may be a useful tool for the construction of a functional vaccine to treat B cell-related disorders.     

Immunogenicity of multi-epitope-based vaccine candidates administered with the adjuvant Gp96 against rabies

Rabies, a zoonotic disease, causes 55,000 human deaths globally and results in at least 500 million dollars in losses every year. The currently available rabies vaccines are mainly inactivated and attenuated vaccines, which have been linked with clinical diseases in animals. Thus, a rabies vaccine with high safety and efficacy is urgently needed. Peptide vaccines are known for their low cost, simple production procedures and high safety. Therefore, in this study, we examined the efficacy of multi-epitope-based vaccine candidates against rabies virus. The ability of various peptides to induce epitope-specific responses was examined, and the two peptides that possessed the highest antigenicity and conservation, i.e., AR16 and h PAB, were coated with adjuvant canineGp96 and used to prepare vaccines. The peptides were prepared as an emulsion of oil in water(O/W) to create three batches of bivalent vaccine products. The vaccine candidates possessed high safety. Virus neutralizing antibodies were detected on the day 14 after the first immunization in mice and beagles, reaching 5–6 IU/m L in mice and 7–9 IU/m L in beagles by day 28. The protective efficacy of the vaccine candidates was about 70%–80% in mice challenged by a virulent strain of rabies virus. Thus, a novel multi-epitope-based rabies vaccine with Gp96 as an adjuvant was developed and validated in mice and dogs. Our results suggest that synthetic peptides hold promise for the development of novel vaccines against rabies.     

针对结核分枝杆菌潜伏感染的DNA疫苗V569免疫原性及保护性的初步研究

为研究针对结核分枝杆菌潜伏感染的DNA疫苗,基于质粒A39构建了p-VAX1-Ag85B-Rv3425-Rv2029c-PPE26 (V569)质粒DNA,并对其免疫原性及保护性进行初步研究。免疫性评价试验共分6组：PBS、p-VAX1-Ag85B(A)、p-VAX1-Ag85B-Rv3425(A3)、A39、V569和BCG,采用左后腿肌内注射C57BL/6小鼠,用流式细胞术和酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)分别检测细胞免疫和体液免疫水平;构建斑马鱼-海分枝杆菌潜伏感染模型,将PBS、A、A3、A39、BCG、V569分别通过腹腔注射免疫斑马鱼后,每日注射地塞米松10ug诱导海分枝杆菌复发感染,对斑马鱼肝脏进行菌落计数并绘制生存曲线。结果显示,与BCG组相比,V569能引发实验小鼠强烈的细胞免疫反应(IFN-γ高水平分泌),外周血CD4^＋/CD8^＋ T细胞比例明显增加。在斑马鱼-海分枝杆菌潜伏感染复发模型中,与BCG 免疫组相比,V569免疫斑马鱼后可显著减少其肝脏中海分枝杆菌数量,斑马鱼存活情况得到显著改善,表明V569 DNA疫苗可能是一种抗结核潜伏感染的候选DNA疫苗。     

Immunogenicity of a vaccine made from soluble Proteus antigens

Hemagglutinins with different specificity were determined in 270 subjects: of these, 101 were examined in the time course before and after immunization with Proteus vaccine prepared from soluble antigens. The preparation possessed pronounced immunological potency and stimulated the formation of antibodies to the vaccine strain, to heterologous Proteus strains and to the common antigens of Gram-negative bacteria. The combined scheme of the subcutaneous and local administration of the above-mentioned Proteus vaccine ensured an increase in the synthesis of IgM and IgA in patients with Proteus wound infection. Active immunization ensured an essential rise in the level of hemagglutinins to Re-glycolipid in donors and oncological patients not infected with Proteus, but did not ensure the statistically significant shifts in the antibody level to Re-glycolipids in patients with chronic Proteus infection.     

Development of a Listeria monocytogenes based vaccine against prostate cancer

Prostate specific antigen (PSA) is a likely immunotherapeutic target antigen for prostate cancer, the second leading cause of cancer-related death in American men. Previously, we demonstrated that attenuated strains of Listeria monocytogenes (Lm) can be used as effective vaccine vectors for delivery of tumor antigens causing regression of established tumors accompanied by strong immune responses toward these antigens in murine models of cancer. In the present study, we have developed and characterized a recombinant live attenuated L. monocytogenes/PSA (Lm–LLO–PSA) vaccine with potential use for the treatment of pCa. Human PSA gene was cloned into and expressed by an attenuated Lm strain. This recombinant bacterial vaccine, Lm–LLO–PSA was tested for stability, virulence, immunogenicity and anti-tumor effects in a murine model for pCa. Immunization with Lm–LLO–PSA was shown to lower the number of tumor infiltrating T regulatory cells and cause complete regression of over 80% of tumors formed by an implanted genetically modified mouse prostate adenocarcinoma cell line, which expressed human PSA. Lm–LLO–PSA was immunogenic in C57BL/6 mice and splenocytes from mice immunized with Lm–LLO–PSA showed significantly higher number of IFN-γ secreting cells over that of the naïve animals in response to a PSA H2Db-specific peptide, as measured by both, ELISpot and intracellular cytokine staining. In addition, using a CTL assay we show that the T cells specific for PSA were able to recognize and lyse PSA-peptide pulsed target cells in vitro. In a comparison study with two other PSA-based vaccines (a pDNA and a vaccinia vaccine), Lm–LLO–PSA was shown to be more efficacious in regressing established tumors when used in a homologues prime/boost regimen. Together, these results indicate that Lm–LLO–PSA is a potential candidate for pCa immunotherapy and should be further developed.     

脑膜炎球菌疫苗血清学评价的相关研究进展

研究证明,脑膜炎球菌荚膜多糖、多糖蛋白结合物以及外膜蛋白等物质都能够诱导产生抗体,帮助保护机体抵御脑膜炎球菌疾病。阐述了脑膜炎球菌疫苗研制过程中特异性抗体的检测方法以及在疫苗效果评价中的意义,指出在脑膜炎球菌疫苗的效果评价中,抗体含量以及功能性抗体活性的检测是重要指标,为疫苗的市场应用提供了依据。     

Development of a mucosal complex vaccine against oral Salmonella infection in mice

We examined the immunogenicity of a Salmonella enterica complex vaccine (CV), consisting of flagellin and polysome purified from serotype Typhimurium LT2. CV plus cholera toxin (CT), in three oral doses given at 7-day intervals, conferred complete protection on C57BL/6 mice against lethal oral infection with a wild-type strain. It elicited mucosal IgA > IgG2a > IgG1 and systemic IgG2a > IgG1 > IgA antibodies to flagellin and polysome, and delayed footpad response (DFR) to both antigens. In Peyer's patches (PPs) and lamina propria (LP), IgA was produced under a Th1-dominant environment; CD4+T cells from produced interleukin (IL)-2, interferon (IFN)-gamma, and IL-10 by stimulation with salmonella extract. On the same protocol, flagellin plus CT induced flagellin-specific mucosal and systemic IgA and IgG1 antibodies, CD4+T cells producing IL-10 and IFN-gamma in PPs and LP, and only minimal levels of flagellin-specific DFR. Polysome plus CT induced polysome-specific mucosal and systemic IgG2a in addition to IgG1 and IgA antibodies, CD4+T cells producing IFN-gamma and IL-2 in PPs and LP, and polysome-specific DFR. These two vaccines, however, conferred at most 50-60% survival rates. Our results suggest that polysomes in CV provide effective adjuvant activity for the induction of both mucosal and systemic Th1-biased responses toward flagellin.     

Immunogenicity and efficacy of a chimpanzee adenovirus-vectored Rift Valley Fever vaccine in mice

Background

Rift Valley Fever (RVF) is a viral zoonosis that historically affects livestock production and human health in sub-Saharan Africa, though epizootics have also occurred in the Arabian Peninsula. Whilst an effective live-attenuated vaccine is available for livestock, there is currently no licensed human RVF vaccine. Replication-deficient chimpanzee adenovirus (ChAd) vectors are an ideal platform for development of a human RVF vaccine, given the low prevalence of neutralizing antibodies against them in the human population, and their excellent safety and immunogenicity profile in human clinical trials of vaccines against a wide range of pathogens.

Methods

Here, in BALB/c mice, we evaluated the immunogenicity and efficacy of a replication-deficient chimpanzee adenovirus vector, ChAdOx1, encoding the RVF virus envelope glycoproteins, Gn and Gc, which are targets of virus neutralizing antibodies. The ChAdOx1-GnGc vaccine was assessed in comparison to a replication-deficient human adenovirus type 5 vector encoding Gn and Gc (HAdV5-GnGc), a strategy previously shown to confer protective immunity against RVF in mice.

Results

A single immunization with either of the vaccines conferred protection against RVF virus challenge eight weeks post-immunization. Both vaccines elicited RVF virus neutralizing antibody and a robust CD8⁺ T cell response.

Conclusions

Together the results support further development of RVF vaccines based on replication-deficient adenovirus vectors, with ChAdOx1-GnGc being a potential candidate for use in future human clinical trials.

     

Immunogenicity of a recombinant MVA and a DNA vaccine for Japanese encephalitis virus in swine

We previously reported that mice immunized with recombinant modified vaccinia virus Ankara (MVA) encoding Japanese encephalitis virus (JEV) prM and E genes were completely protected against JEV challenge (Nam, J.H., Wyatt, L.S., Chae, S.L., Cho, H.W., Park, Y.K., Moss, B. Vaccine 1999,17: 261-268). In this study, we examined the immunogenicity in swine of this recombinant MVA (vJH9) or a DNA vaccine (pcJH-1) expressing the same JEV genes. Although the booster effect in mice with a combination of vJH9, pcJH-1 and inactivated JEV commercial vaccine was not apparent by measuring JEV antibodies, the recombinant MVA vaccine (vJH9) and the DNA vaccine (pcJH-l) efficiently produced neutralizing antibodies in swine and 2 doses of each showed a booster effect in mice and swine. Therefore, both vJH9 and pcJH-1 are good candidates for a second generation JEV vaccine.     

登革病毒共有序列候选DNA疫苗的免疫原性和保护性研究

目的研究登革病毒(Dengue virus, DENV)共有序列候选DNA疫苗pVAX1-cE80在小鼠体内的免疫原性及其保护作用。方法首先利用pVAX1-cE80 DNA免疫BALB/c小鼠,通过ELISA和噬斑减少中和试验(plaque reduction neutralization test, PRNT)分别检测免疫后小鼠血清中抗登革病毒的4种血清型(dengue virus serotype 1-4, DENV1-4)IgG抗体和中和抗体(neutralizing antibody, nAb)效价;利用酶联免疫斑点试验(enzyme-linked immunospot assay, ELISPOT)检测小鼠脾细胞分泌DENV1-4特异性Th1/Th2型细胞因子的能力;通过攻毒试验评价疫苗对DENV1-4感染的保护作用。结果接种疫苗的小鼠可产生针对DENV1-4的四价抗体,其中抗DENV2抗体水平最高,IgG抗体和nAb效价分别为1∶1 086和1∶120;免疫后小鼠脾细胞在DENV1-4抗原刺激下均可分泌较高水平的IFN-γ和IL-4;疫苗免疫可为小鼠提供针对DENV1-4的部分保护作用。结论单一共有序列登革病毒候选DNA疫苗可诱导小鼠产生四价体液免疫反应和细胞免疫反应,并为小鼠提供部分保护作用,为登革病毒共有序列疫苗的研发奠定了基础。     

Immunogenicity of Mycobacterium ulcerans Hsp65 and protective efficacy of a Mycobacterium leprae Hsp65-based DNA vaccine against Buruli ulcer

Buruli ulcer, a disease caused by Mycobacterium ulcerans, is emerging as an increasingly important cause of morbidity throughout the world, for which surgery is the only efficient treatment to date. The aim of this work was to identify potential vaccine candidates in an experimental model of mouse infection. In BALB/c mice infected with M. ulcerans subcutaneously, Hsp65 appeared to be an immunodominant antigen eliciting both humoral and cellular responses. However, vaccination of mice with a DNA vector encoding Mycobacterium leprae Hsp65 only poorly limited the progression of M. ulcerans infection. In contrast, a substantial degree of protection was conferred by subcutaneous vaccination with BCG, suggesting that BCG antigens that are conserved in M. ulcerans, such as TB10.4, the 19 kDa antigen, PstS3 and Hsp70, may be interesting to consider as subunit vaccines in future prospects.     

Genome sequence of Mycobacterium bovis BCG Moreau, the Brazilian vaccine strain against tuberculosis

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine available against tuberculosis, and the strains used worldwide represent a family of daughter strains with distinct genotypic characteristics. Here we report the complete genome sequence of M. bovis BCG Moreau, the strain in continuous use in Brazil for vaccine production since the 1920s.     

伤寒结合疫苗免疫原性和动物安全性研究

伤寒V i多糖与白喉类毒素(DT)蛋白以己二酰肼(ADH)作连接臂,在碳二亚胺(EDAC)的作用下结合成V i-DT结合物,进行抗原性、免疫原性和动物安全性试验。结果显示,3批结合物抗体阳转率均为100%,加强免疫一针后GMT值明显升高(p<0.001),免疫剂量以0.75μg/只抗体增长最为明显,甚至以低剂量0.375μg/只仍能获得较高的抗体滴度,多项动物试验证明该结合物是安全的。显示V i-DT结合物有很好的动物安全性和免疫原性,为临床试验提供实验室依据。     

伤寒Vi-rEPA结合疫苗在小鼠中的免疫原性研究

以伤寒Vi多糖疫苗及结合物含量分别为20％、40％、60％的伤寒Vi-rEPA结合疫苗经皮下免疫小鼠后眼眶采血分离血清,用ELISA法测血清抗体浓度。血清抗体分析表明,伤寒Vi多糖疫苗和伤寒Vi-rEPA结合疫苗均有良好的免疫原性,但伤寒Vi-rEPA结合疫苗的免疫原性优于伤寒Vi多糖疫苗;伤寒Vi多糖疫苗无加强免疫应答效应,而伤寒Vi-rEPA结合疫苗有加强免疫应答效应;不同高分子结合物含量的伤寒Vi-rEPA结合疫苗免疫小鼠,其结合物含量为40％、60％的伤寒Vi-rEPA结合疫苗比结合物含量为20％的结合疫苗具有更好的免疫原性,而前二者的免疫原性无显著性差异。