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Sample records for attenuated vaccine development

  1. Research progress in live attenuated Brucella vaccine development.

    PubMed

    Wang, Zhen; Wu, Qingmin

    2013-01-01

    Brucella spp. are facultative intracellular bacteria that cause brucellosis, which is a globally occurring zoonotic disease that is characterized by abortion in domestic animals and undulant fever, arthritis, endocarditis, and meningitis in humans. There are currently no licensed vaccines against brucellosis for human use, and only a few licensed live Brucella vaccines are available for use in animals. However, the available animal vaccines may cause abortion and are associated with lower protection rates in animals and higher virulence in humans. Much research has been performed recently to develop novel Brucella vaccines for the prevention and control of animal brucellosis. This article discusses the approaches and strategies for novel live attenuated vaccine development.

  2. Live attenuated hepatitis A vaccines developed in China.

    PubMed

    Xu, Zhi-Yi; Wang, Xuan-Yi

    2014-01-01

    Two live, attenuated hepatitis A vaccines, H 2 and LA-1 virus strains, were developed through serial passages of the viruses in cell cultures at 32 °C and 35 °C respectively. Both vaccines were safe and immunogenic, providing protection against clinical hepatitis A in 95% of the vaccinees, with a single dose by subcutaneous injection. The vaccine recipients were not protected from asymptomatic, subclinical hepatitis A virus (HAV) infection, which induced a similar antibody response as for unvaccinated subjects. A second dose caused anamnestic response and can be used for boosting. Oral immunization of human with H 2 vaccine or of marmoset with LA-1 vaccine failed, and no evidence was found for person-to-person transmission of the H 2 strain or for marmoset-to-marmoset transmission of LA-1 strain, by close contact. H 2 strain was genetically stable when passaged in marmosets, humans or cell cultures at 37 °C; 3 consecutive passages of the virus in marmosets did not cause virulence mutation. The live vaccines offer the benefits of low cost, single dose injection, long- term protection, and increased duration of immunity through subclinical infection. Improved sanitation and administration of 150 million doses of the live vaccines to children had led to a 90% reduction in the annual national incidence rate of hepatitis A in China during the 16-year period, from 1991 to 2006. Hepatitis A immunization with both live and inactivated HA vaccines was implemented in the national routine childhood immunization program in 2008 and around 92% of the 16 million annual births received the affordable live, attenuated vaccines at 18 months of age. Near elimination of the disease was achieved in China for 14 years following introduction of the H 2 live vaccine into the Expanded Immunization Program (EPI) in 1992.

  3. Development of live attenuated influenza vaccines against pandemic influenza strains.

    PubMed

    Coelingh, Kathleen L; Luke, Catherine J; Jin, Hong; Talaat, Kawsar R

    2014-07-01

    Avian and animal influenza viruses can sporadically transmit to humans, causing outbreaks of varying severity. In some cases, further human-to-human virus transmission does not occur, and the outbreak in humans is limited. In other cases, sustained human-to-human transmission occurs, resulting in worldwide influenza pandemics. Preparation for future pandemics is an important global public health goal. A key objective of preparedness is to gain an understanding of how to design, test, and manufacture effective vaccines that could be stockpiled for use in a pandemic. This review summarizes results of an ongoing collaboration to produce, characterize, and clinically test a library of live attenuated influenza vaccine strains (based on Ann Arbor attenuated Type A strain) containing protective antigens from influenza viruses considered to be of high pandemic potential.

  4. Using recombinant DNA technology for the development of live-attenuated dengue vaccines.

    PubMed

    Lee, Hsiang-Chi; Butler, Michael; Wu, Suh-Chin

    2012-07-15

    Dramatic increases in dengue (DEN) incidence and disease severity have been reported, in great part due to the geographic expansion of Aedes aegypti and Aedes albopictus mosquitoes. One result is the expanded co-circulation of all dengue 1-4 serotype viruses (DENV) in urban areas worldwide, especially in South and South-East Asia, and South America. DEN disease severity ranges from asymptomatic infections to febrile dengue fevers (DF) to life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). There is an urgent need for a safe and effective tetravalent DEN vaccine. Several live attenuated, tetravalent DEN vaccine candidates have been generated by recombinant DNA technology; these candidates are capable of providing immunity to all four DENV serotypes. In this paper we review (a) recombinant live-attenuated DEN vaccine candidates in terms of deletion, antigen chimerization, and the introduction of adaptive mutations; (b) strategies for improving tetravalent vaccine attenuation; and (c) live-attenuated DENV vaccine development.

  5. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design

    SciTech Connect

    Yamshchikov, Vladimir Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-15

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E{sub 138}K and K{sub 279}M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use. - Highlights: • Further attenuation of a WN vaccine precursor is outlined. • Effect of SA14-14-2 attenuating mutations is tested. • Mechanism of attenuation is proposed and illustrated. • The need for additional attenuating mutations is justified.

  6. Development of a human live attenuated West Nile infectious DNA vaccine: conceptual design of the vaccine candidate.

    PubMed

    Yamshchikov, Vladimir

    2015-10-01

    West Nile virus has become an important epidemiological problem attracting significant attention of health authorities, mass media, and the public. Although there are promising advancements toward addressing the vaccine need, the perspectives of the commercial availability of the vaccine remain uncertain. To a large extent this is due to lack of a sustained interest for further commercial development of the vaccines already undergoing the preclinical and clinical development, and a predicted insignificant cost effectiveness of mass vaccination. There is a need for a safe, efficacious and cost effective vaccine, which can improve the feasibility of a targeted vaccination program. In the present report, we summarize the background, the rationale, and the choice of the development pathway that we selected for the design of a live attenuated human West Nile vaccine in a novel infectious DNA format.

  7. Development of live attenuated Streptococcus agalactiae as potential vaccines by selecting for resistance to sparfloxacin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To develop attenuated bacteria as potential live vaccines, sparfloxacin was used in this study to modify 40 isolates of Streptococcus agalactiae. Majority of S. agalactiae used in this study were able to develop at least 80-fold resistance to sparfloxacin. When the virulence of the sparfloxacin-resi...

  8. Development of Live-Attenuated Arenavirus Vaccines Based on Codon Deoptimization

    PubMed Central

    Cheng, Benson Yee Hin; Ortiz-Riaño, Emilio; Nogales, Aitor

    2015-01-01

    ABSTRACT Arenaviruses have a significant impact on public health and pose a credible biodefense threat, but the development of safe and effective arenavirus vaccines has remained elusive, and currently, no Food and Drug Administration (FDA)-licensed arenavirus vaccines are available. Here, we explored the use of a codon deoptimization (CD)-based approach as a novel strategy to develop live-attenuated arenavirus vaccines. We recoded the nucleoprotein (NP) of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) with the least frequently used codons in mammalian cells, which caused lower LCMV NP expression levels in transfected cells that correlated with decreased NP activity in cell-based functional assays. We used reverse-genetics approaches to rescue a battery of recombinant LCMVs (rLCMVs) encoding CD NPs (rLCMV/NPCD) that showed attenuated growth kinetics in vitro. Moreover, experiments using the well-characterized mouse model of LCMV infection revealed that rLCMV/NPCD1 and rLCMV/NPCD2 were highly attenuated in vivo but, upon a single immunization, conferred complete protection against a subsequent lethal challenge with wild-type (WT) recombinant LCMV (rLCMV/WT). Both rLCMV/NPCD1 and rLCMV/NPCD2 were genetically and phenotypically stable during serial passages in FDA vaccine-approved Vero cells. These results provide proof of concept of the safety, efficacy, and stability of a CD-based approach for developing live-attenuated vaccine candidates against human-pathogenic arenaviruses. IMPORTANCE Several arenaviruses cause severe hemorrhagic fever in humans and pose a credible bioterrorism threat. Currently, no FDA-licensed vaccines are available to combat arenavirus infections, while antiarenaviral therapy is limited to the off-label use of ribavirin, which is only partially effective and is associated with side effects. Here, we describe the generation of recombinant versions of the prototypic arenavirus LCMV encoding codon-deoptimized viral

  9. General Molecular Strategy for Development of Arenavirus Live-Attenuated Vaccines

    PubMed Central

    Iwasaki, Masaharu; Ngo, Nhi; Cubitt, Beatrice; Teijaro, John R.

    2015-01-01

    ABSTRACT Hemorrhagic fever arenaviruses (HFA) pose important public health problems in regions where they are endemic. Thus, Lassa virus (LASV) infects several hundred thousand individuals yearly in West Africa, causing a large number of Lassa fever cases associated with high morbidity and mortality. Concerns about human-pathogenic arenaviruses are exacerbated because of the lack of FDA-licensed arenavirus vaccines and because current antiarenaviral therapy is limited to an off-label use of ribavirin that is only partially effective. The Mopeia virus (MOPV)/LASV reassortant (ML29) is a LASV candidate live-attenuated vaccine (LAV) that has shown promising results in animal models. Nevertheless, the mechanism of ML29 attenuation remains unknown, which raises concerns about the phenotypic stability of ML29 in response to additional mutations. Development of LAVs based on well-defined molecular mechanisms of attenuation will represent a major step in combatting HFA. We used the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) to develop a general molecular strategy for arenavirus attenuation. Our approach involved replacement of the noncoding intergenic region (IGR) of the L genome segment with the IGR of the S genome segment to generate a recombinant LCMV, rLCMV(IGR/S-S), that was highly attenuated in vivo but induced protection against a lethal challenge with wild-type LCMV. Attenuation of rLCMV(IGR/S-S) was associated with a stable reorganization of the control of viral gene expression. This strategy can facilitate the rapid development of LAVs with the antigenic composition of the parental HFA and a mechanism of attenuation that minimizes concerns about increased virulence that could be caused by genetic changes in the LAV. IMPORTANCE Hemorrhagic fever arenaviruses (HFA) cause high morbidity and mortality, and pose important public health problems in the regions where they are endemic. Implementation of live-attenuated vaccines (LAV) will represent a

  10. Development of live-attenuated arenavirus vaccines based on codon deoptimization of the viral glycoprotein.

    PubMed

    Cheng, Benson Y H; Nogales, Aitor; de la Torre, Juan Carlos; Martínez-Sobrido, Luis

    2017-01-15

    Several arenaviruses, chiefly Lassa (LASV) in West Africa, cause hemorrhagic fever (HF) disease in humans and pose important public health problems in their endemic regions. To date, there are no FDA-approved arenavirus vaccines and current anti-arenaviral therapy is limited to the use of ribavirin that has very limited efficacy. In this work we document that a recombinant prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) with a codon deoptimized (CD) surface glycoprotein (GP), rLCMV/CD, exhibited wild type (WT)-like growth properties in cultured cells despite barely detectable GP expression levels in rLCMV/CD-infected cells. Importantly, rLCMV/CD was highly attenuated in vivo but able to induce complete protection against a subsequent lethal challenge with rLCMV/WT. Our findings support the feasibility of implementing an arenavirus GP CD-based approach for the development of safe and effective live-attenuated vaccines (LAVs) to combat diseases caused by human pathogenic arenaviruses.

  11. Live attenuated vaccines for invasive Salmonella infections

    PubMed Central

    Tennant, Sharon M.; Levine, Myron M.

    2015-01-01

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed S. Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: S. Typhi, S. Paratyphi A, S. Paratyphi B (currently uncommon but may become dominant again), S. Typhimurium, S. Enteritidis and S. Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines. PMID:25902362

  12. Live attenuated vaccines for invasive Salmonella infections.

    PubMed

    Tennant, Sharon M; Levine, Myron M

    2015-06-19

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines.

  13. Development of TV003/TV005, a single dose, highly immunogenic live attenuated dengue vaccine; what makes this vaccine different from the Sanofi-Pasteur CYD™ vaccine?

    PubMed

    Whitehead, Stephen S

    2016-01-01

    Dengue is caused by four serotype-distinct dengue viruses (DENVs), and developing a multivalent vaccine against dengue has not been straightforward since partial immunity to DENV may predispose to more severe disease upon subsequent DENV infection. The vaccine that is furthest along in development is CYD™, a live attenuated tetravalent vaccine (LATV) produced by Sanofi Pasteur. Although the multi-dose vaccine demonstrated protection against severe dengue, its overall efficacy was limited by DENV serotype, serostatus at vaccination, region and age. The National Institute of Allergy and Infectious Diseases has developed the LATV dengue vaccines TV003/TV005. A single dose of either TV003 or TV005 induced seroconversion to four DENV serotypes in 74-92% (TV003) and 90% (TV005) of flavivirus seronegative adults and elicited near-sterilizing immunity to a second dose of vaccine administered 6-12 months later. The important differences in the structure, infectivity and immune responses to TV003/TV005 are compared with CYD™.

  14. Progress toward the development of a genetically engineered attenuated hepatitis A virus vaccine.

    PubMed Central

    Funkhouser, A W; Raychaudhuri, G; Purcell, R H; Govindarajan, S; Elkins, R; Emerson, S U

    1996-01-01

    Mutations which positively affect growth of hepatitis A virus in cell culture may negatively affect growth in vivo. Therefore, development of an attenuated vaccine for hepatitis A may require a careful balancing of mutations to produce a virus that will grow efficiently in cells suitable for vaccine production and still maintain a satisfactory level of attenuation in vivo. Since such a balance could be achieved most directly by genetic engineering, we are analyzing mutations that accumulated during serial passage of the HM-175 strain of hepatitis A virus in MRC-5 cell cultures in order to determine the relative importance of the mutations for growth in MRC-5 cells and for attenuation in susceptible primates. Chimeric viral genomes of the HM-175 strain were constructed from cDNA clones derived from a virulent virus and from two attenuated viruses adapted to growth in African green monkey kidney (AGMK) and MRC-5 cells, respectively. Viruses encoded by these chimeric genomes were recovered by in vitro or in vivo transfection and assessed for their ability to grow in cultured MRC-5 cells or to cause hepatitis in primates (tamarins). The only MRC-5-specific mutations that substantially increased the efficiency of growth in MRC-5 cells were a group of four mutations in the 5' noncoding (NC) region. These 5' NC mutations and a separate group of 5' NC mutations that accumulated during earlier passages of the HM-175 virus in primary AGMK cells appeared, independently and additively, to result in decreased biochemical evidence of hepatitis in tamarins. However, neither group of 5' NC mutations had a demonstrable effect on the extent of virus excretion or liver pathology in these animals. PMID:8892918

  15. Progress toward the development of a genetically engineered attenuated hepatitis A virus vaccine.

    PubMed

    Funkhouser, A W; Raychaudhuri, G; Purcell, R H; Govindarajan, S; Elkins, R; Emerson, S U

    1996-11-01

    Mutations which positively affect growth of hepatitis A virus in cell culture may negatively affect growth in vivo. Therefore, development of an attenuated vaccine for hepatitis A may require a careful balancing of mutations to produce a virus that will grow efficiently in cells suitable for vaccine production and still maintain a satisfactory level of attenuation in vivo. Since such a balance could be achieved most directly by genetic engineering, we are analyzing mutations that accumulated during serial passage of the HM-175 strain of hepatitis A virus in MRC-5 cell cultures in order to determine the relative importance of the mutations for growth in MRC-5 cells and for attenuation in susceptible primates. Chimeric viral genomes of the HM-175 strain were constructed from cDNA clones derived from a virulent virus and from two attenuated viruses adapted to growth in African green monkey kidney (AGMK) and MRC-5 cells, respectively. Viruses encoded by these chimeric genomes were recovered by in vitro or in vivo transfection and assessed for their ability to grow in cultured MRC-5 cells or to cause hepatitis in primates (tamarins). The only MRC-5-specific mutations that substantially increased the efficiency of growth in MRC-5 cells were a group of four mutations in the 5' noncoding (NC) region. These 5' NC mutations and a separate group of 5' NC mutations that accumulated during earlier passages of the HM-175 virus in primary AGMK cells appeared, independently and additively, to result in decreased biochemical evidence of hepatitis in tamarins. However, neither group of 5' NC mutations had a demonstrable effect on the extent of virus excretion or liver pathology in these animals.

  16. Development and clinical evaluation of multiple investigational monovalent DENV vaccines to identify components for inclusion in a live attenuated tetravalent DENV vaccine.

    PubMed

    Durbin, Anna P; Kirkpatrick, Beth D; Pierce, Kristen K; Schmidt, Alexander C; Whitehead, Stephen S

    2011-09-23

    The Laboratory of Infectious Diseases at the National Institute of Allergy and Infectious Diseases, National Institutes of Health has been engaged in an effort to develop a safe, efficacious, and affordable live attenuated tetravalent dengue vaccine (LATV) for more than ten years. Numerous recombinant monovalent DENV vaccine candidates have been evaluated in the SCID-HuH-7 mouse and in rhesus macaques to identify those candidates with a suitable attenuation phenotype. In addition, the ability of these candidates to infect and disseminate in Aedes mosquitoes had also been determined. Those candidates that were suitably attenuated in SCID-HuH-7 mice, rhesus macaques, and mosquitoes were selected for further evaluation in humans. This review will describe the generation of multiple candidate vaccines directed against each DENV serotype, the preclinical and clinical evaluation of these candidates, and the process of selecting suitable candidates for inclusion in a LATV dengue vaccine.

  17. Development of live-attenuated arenavirus vaccines based on codon deoptimization of the viral glycoprotein

    PubMed Central

    Cheng, Benson Y.H.; Nogales, Aitor; de la Torre, Juan Carlos; Martínez-Sobrido, Luis

    2016-01-01

    Several arenaviruses, chiefly Lassa (LASV) in West Africa, cause hemorrhagic fever (HF) disease in humans and pose important public health problems in their endemic regions. To date, there are no FDA-approved arenavirus vaccines and current anti-arenaviral therapy is limited to the use of ribavirin that has very limited efficacy. In this work we dcument that a recombinant prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) with a codon deoptimized (CD) surface glycoprotein (GP), rLCMV/CD, exhibited wild type (WT)-like growth properties in cultured cells despite barely detectable GP expression levels in rLCMV/CD-infected cells. Importantly, rLCMV/CD was highly attenuated in vivo but able to induce complete protection against a subsequent lethal challenge with rLCMV/WT. Our findings support the feasibility of implementing an arenavirus GP CD-based approach for the development of safe and effective live-attenuated vaccines (LAVs) to combat diseases caused by human pathogenic arenaviruses. PMID:27855284

  18. Development of a Live Attenuated Bivalent Oral Vaccine Against Shigella sonnei Shigellosis and Typhoid Fever.

    PubMed

    Wu, Yun; Chakravarty, Sumana; Li, Minglin; Wai, Tint T; Hoffman, Stephen L; Sim, B Kim Lee

    2017-01-15

    Shigella sonnei and Salmonella Typhi cause significant morbidity and mortality. We exploited the safety record of the oral, attenuated S. Typhi vaccine (Ty21a) by using it as a vector to develop a bivalent oral vaccine to protect against S. sonnei shigellosis and typhoid fever. We recombineered the S. sonnei form I O-antigen gene cluster into the Ty21a chromosome to create Ty21a-Ss, which stably expresses S. sonnei form I O antigen. To enhance survivability in the acid environment of the stomach, we created an acid-resistant strain, Ty21a-AR-Ss, by inserting Shigella glutaminase-glutamate decarboxylase systems coexpressed with S. sonnei form I O-antigen gene. Mice immunized intranasally with Ty21a-AR-Ss produced antibodies against S. sonnei and S. Typhi, and survived lethal intranasal S. sonnei challenge. This paves the way for proposed good manufacturing practices manufacture and clinical trials intended to test the clinical effectiveness of Ty21a-AR-Ss in protecting against S. sonnei shigellosis and typhoid fever, as compared with the current Ty21a vaccine.

  19. A pilot study comparing the development of EIAV Env-specific antibodies induced by DNA/recombinant vaccinia-vectored vaccines and an attenuated Chinese EIAV vaccine.

    PubMed

    Meng, Qinglai; Lin, Yuezhi; Ma, Jian; Ma, Yan; Zhao, Liping; Li, Shenwei; Yang, Kai; Zhou, Jianhua; Shen, Rongxian; Zhang, Xiaoyan; Shao, Yiming

    2012-12-01

    Data from successful attenuated lentiviral vaccine studies indicate that fully mature Env-specific antibodies characterized by high titer, high avidity, and the predominant recognition of conformational epitopes are associated with protective efficacy. Although vaccination with a DNA prime/recombinant vaccinia-vectored vaccine boost strategy has been found to be effective in some trials with non-human primate/simian/human immunodeficiency virus (SHIV) models, it remains unclear whether this vaccination strategy could elicit mature equine infectious anemia virus (EIAV) Env-specific antibodies, thus protecting vaccinated horses against EIAV infection. Therefore, in this pilot study we vaccinated horses using a strategy based on DNA prime/recombinant Tiantan vaccinia (rTTV)-vectored vaccines encoding EIAV env and gag genes, and observed the development of Env-specific antibodies, neutralizing antibodies, and p26-specific antibodies. Vaccination with DNA induced low titer, low avidity, and the predominant recognition of linear epitopes by Env-specific antibodies, which was enhanced by boosting vaccinations with rTTV vaccines. However, the maturation levels of Env-specific antibodies induced by the DNA/rTTV vaccines were significantly lower than those induced by the attenuated vaccine EIAV(FDDV). Additionally, DNA/rTTV vaccines did not elicit broadly neutralizing antibodies. After challenge with a virulent EIAV strain, all of the vaccinees and control horses died from EIAV disease. These data indicate that the regimen of DNA prime/rTTV vaccine boost did not induce mature Env-specific antibodies, which might have contributed to immune protection failure.

  20. Rational Development of an Attenuated Recombinant Cyprinid Herpesvirus 3 Vaccine Using Prokaryotic Mutagenesis and In Vivo Bioluminescent Imaging

    PubMed Central

    Boutier, Maxime; Ronsmans, Maygane; Ouyang, Ping; Fournier, Guillaume; Reschner, Anca; Rakus, Krzysztof; Wilkie, Gavin S.; Farnir, Frédéric; Bayrou, Calixte; Lieffrig, François; Li, Hong; Desmecht, Daniel; Davison, Andrew J.; Vanderplasschen, Alain

    2015-01-01

    Cyprinid herpesvirus 3 (CyHV-3) is causing severe economic losses worldwide in common and koi carp industries, and a safe and efficacious attenuated vaccine compatible with mass vaccination is needed. We produced single deleted recombinants using prokaryotic mutagenesis. When producing a recombinant lacking open reading frame 134 (ORF134), we unexpectedly obtained a clone with additional deletion of ORF56 and ORF57. This triple deleted recombinant replicated efficiently in vitro and expressed an in vivo safety/efficacy profile compatible with use as an attenuated vaccine. To determine the role of the double ORF56-57 deletion in the phenotype and to improve further the quality of the vaccine candidate, a series of deleted recombinants was produced and tested in vivo. These experiments led to the selection of a double deleted recombinant lacking ORF56 and ORF57 as a vaccine candidate. The safety and efficacy of this strain were studied using an in vivo bioluminescent imaging system (IVIS), qPCR, and histopathological examination, which demonstrated that it enters fish via skin infection similar to the wild type strain. However, compared to the parental wild type strain, the vaccine candidate replicated at lower levels and spread less efficiently to secondary sites of infection. Transmission experiments allowing water contamination with or without additional physical contact between fish demonstrated that the vaccine candidate has a reduced ability to spread from vaccinated fish to naïve sentinel cohabitants. Finally, IVIS analyses demonstrated that the vaccine candidate induces a protective mucosal immune response at the portal of entry. Thus, the present study is the first to report the rational development of a recombinant attenuated vaccine against CyHV-3 for mass vaccination of carp. We also demonstrated the relevance of the CyHV-3 carp model for studying alloherpesvirus transmission and mucosal immunity in teleost skin. PMID:25700279

  1. Attempt to develop live attenuated bacterial vaccines by selecting resistance to gossypol, proflavine hemisulfate, novobiocin, or ciprofloxacin.

    PubMed

    Pridgeon, Julia W; Klesius, Phillip H; Yildirim-Aksoy, Mediha

    2013-04-26

    In an attempt to develop attenuated bacteria as potential live vaccines, four chemicals (gossypol, proflavine hemisulfate, novobiocin, and ciprofloxacin) were used to modify the following four genera of bacteria through chemical-resistance strategy: (1) Aeromonas hydrophila (9 isolates); (2) Edwardsiella tarda (9 isolates); (3) Streptococcus iniae (9 isolates); and (4) S. agalactiae (11 isolates). All bacteria used in this study were able to develop high resistance to gossypol. However, only some bacteria were able to develop resistance to proflavine hemisulfate, novobiocin, or ciprofloxacin. When the virulence of resistant bacteria was tested in tilapia or catfish, none of the gossypol-resistant isolate was attenuated, whereas majority of the proflavine hemisulfate-resistant isolates were attenuated. However, all proflavine hemisulfate-attenuated bacteria failed to provide significant protection to fish. Eight novobiocin- or ciprofloxacin-resistant Gram-positive bacteria (S. agalactiae and S. inaie) were found to be attenuated. However, none of them offered protection higher than 70%. Of seven attenuated novobiocin- or ciprofloxacin-resistant Gram-negative isolates (A. hydrophila and E. tarda), only one (novobiocin-resistant E. tarda 30305) was found to safe and highly efficacious. When E. tarda 30305-novo vaccinated Nile tilapia were challenged by its virulent E. tarda 30305, relative percent of survival of vaccinated fish at 14- and 28-days post vaccination (dpv) was 100% and 92%, respectively. Similarly, E. tarda 30305-novo offered 100% protection to channel catfish against challenges with virulent parent isolate E. tarda 30305 at both 14- and 28-dpv. Our results suggest that the development of live attenuated bacterial vaccines that are safe and efficacious is challenging, although it is feasible.

  2. Development of live attenuated Streptococcus agalactiae vaccine for tilapia via continuous passage in vitro.

    PubMed

    Li, L P; Wang, R; Liang, W W; Huang, T; Huang, Y; Luo, F G; Lei, A Y; Chen, M; Gan, X

    2015-08-01

    Fish Streptococcus agalactiae (S. agalactiae) seriously harms the world's aquaculture industry and causes huge economic losses. This study aimed to develop a potential live attenuated vaccine of S. agalactiae. Pre-screened vaccine candidate strain S. agalactiae HN016 was used as starting material to generate an attenuated strain S. agalactiae YM001 by continuous passage in vitro. The biological characteristics, virulence, and stability of YM001 were detected, and the protective efficacy of YM001 immunization in tilapia was also determined. Our results indicated that the growth, staining, characteristics of pulsed-field gel electrophoresis (PFGE) genotype, and virulence of YM001 were changed significantly as compared to the parental strain HN016. High doses of YM001 by intraperitoneal (IP) injection (1.0 × 10(9) CFU/fish) and oral gavage (1.0 × 10(10) CFU/fish) respectively did not cause any mortality and morbidity in tilapia. The relative percent survivals (RPSs) of fishes immunized with YM001 (1.0 × 10(8) CFU/fish, one time) via injection, immersion, and oral administration were 96.88, 67.22, and 71.81%, respectively, at 15 days, and 93.61, 60.56, and 53.16%, respectively, at 30 days. In all tests with 1-3 times of immunization in tilapia, the dosages at 1 × 10(8) and 1 × 10(9) CFU/fish displayed the similar best results, whereas the immunoprotection of the dosages at 1 × 10(6) and 1 × 10(7) CFU/fish declined significantly (P < 0.01), and 1 × 10(5) CFU/fish hardly displayed any protective effect. In addition, the efficacy of 2-3 times of immunization was significantly higher than that of single immunization (P < 0.01) while no significant difference in the efficacy between twice and thrice of immunization was seen (P > 0.05). The level of protective antibody elicited by oral immunization was significantly higher compared to that of the control group (P < 0.01), and the antibody reached their maximum levels 14-21 days after the immunization but decreased

  3. Attempt to develop live attenuated bacterial vaccines by selecting resistance to gossypol, proflavine hemisulfate, novobiocin, or ciprofloxacin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an attempt to develop attenuated bacteria as potential live vaccines, four chemicals (gossypol, proflavine hemisulfate, novobiocin, and ciprofloxacin) were used to modify the following four genera of bacteria through chemical-resistance strategy: 1) Aeromonas hydrophila (9 isolates); 2) Edwardsie...

  4. Attempt to develop live attenuated bacterial vaccines by selecting resistance to gossypol, proflavine hemisulfate, novobiocin, or ciprofloxacin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an attempt to develop attenuated bacteria as potential live vaccines, four chemicals (gossypol, proflavine hemisulfate, novobiocin, and ciprofloxacin) were used to modify the following four genera of bacteria through chemical-resistance strategy: (1) Aeromonas hydrophila (9 isolates); (2) Edwards...

  5. Generation of growth arrested Leishmania amastigotes: a tool to develop live attenuated vaccine candidates against visceral leishmaniasis.

    PubMed

    Selvapandiyan, Angamuthu; Dey, Ranadhir; Gannavaram, Sreenivas; Solanki, Sumit; Salotra, Poonam; Nakhasi, Hira L

    2014-06-30

    Visceral leishmaniasis (VL) is fatal if not treated and is prevalent widely in the tropical and sub-tropical regions of world. VL is caused by the protozoan parasite Leishmania donovani or Leishmania infantum. Although several second generation vaccines have been licensed to protect dogs against VL, there are no effective vaccines against human VL [1]. Since people cured of leishmaniasis develop lifelong protection, development of live attenuated Leishmania parasites as vaccines, which can have controlled infection, may be a close surrogate to leishmanization. This can be achieved by deletion of genes involved in the regulation of growth and/or virulence of the parasite. Such mutant parasites generally do not revert to virulence in animal models even under conditions of induced immune suppression due to complete deletion of the essential gene(s). In the Leishmania life cycle, the intracellular amastigote form is the virulent form and causes disease in the mammalian hosts. We developed centrin gene deleted L. donovani parasites that displayed attenuated growth only in the amastigote stage and were found safe and efficacious against virulent challenge in the experimental animal models. Thus, targeting genes differentially expressed in the amastigote stage would potentially attenuate only the amastigote stage and hence controlled infectivity may be effective in developing immunity. This review lays out the strategies for attenuation of the growth of the amastigote form of Leishmania for use as live vaccine against leishmaniasis, with a focus on visceral leishmaniasis.

  6. Development and approval of live attenuated influenza vaccines based on Russian master donor viruses: Process challenges and success stories.

    PubMed

    Rudenko, Larisa; Yeolekar, Leena; Kiseleva, Irina; Isakova-Sivak, Irina

    2016-10-26

    Influenza is a viral infection that affects much of the global population each year. Vaccination remains the most effective tool for preventing the disease. Live attenuated influenza vaccine (LAIV) has been used since the 1950s to protect humans against seasonal influenza. LAIVs developed by the Institute of Experimental Medicine (IEM), Saint Petersburg, Russia, have been successfully used in Russia since 1987. In 2006, the World Health Organization (WHO) announced a Global action plan for influenza vaccines (GAP). WHO, recognizing potential advantages of LAIV over the inactivated influenza vaccine in a pandemic situation, included LAIV in the GAP. BioDiem Ltd., a vaccine development company based in Melbourne, Australia which held the rights for the Russian LAIV, licensed this technology to WHO in 2009. WHO was permitted to grant sub-licenses to vaccine manufacturers in newly industrialized and developing countries to use the Russian LAIV for the development, manufacture, use and sale of pandemic and seasonal LAIVs. To date, WHO has granted sub-licenses to vaccine manufacturers in China (Changchun BCHT Biotechnology Co., Ltd.), India (Serum Institute of India Pvt. Ltd.) and Thailand (Government Pharmaceutical Organization). In parallel, in 2009, IEM signed an agreement with WHO, under which IEM committed to supply pandemic and seasonal candidate vaccine viruses to the sub-licensees. This paper describes the progress made by collaborators from China, India, Russia and Thailand in developing preventive measures, including LAIV against pandemic influenza.

  7. [History of development of the live poliomyelitis vaccine from Sabin attenuated strains in 1959 and idea of poliomyelitis eradication].

    PubMed

    Lashkevich, V A

    2013-01-01

    In 1958 Poliomyelitis Institute in Moscow and Institute of Experimental Medicine in St. Petersburg received from A. Sabin the attenuated strains of poliomyelitis virus. The characteristics of the strains were thoroughly studied by A. A. Smorodintsev and coworkers. They found that the virulence of the strains fluctuated slightly in 10 consecutive passages through the intestine of the non-immune children. A part of the Sabin material was used by A. A. Smorodintsev and M. P. Chumakov in the beginning of 1959 for immunizing approximately 40000 children in Estonia, Lithuania, and Latvia. Epidemic poliomyelitis rate in these republics decreased from approximately 1000 cases yearly before vaccination to less than 20 in the third quarter of 1959. This was a convincing proof of the efficacy and safety of the vaccine from the attenuated Sabin strains. In 1959, according to A. Sabin's recommendation, a technology of live vaccine production was developed at the Poliomyelitis Institute, and several experimental lots of vaccine were prepared. In the second part of 1959, 13.5 million children in USSR were immunized. The epidemic poliomyelitis rate decreased 3-5 times in different regions without paralytic cases, which could be attributed to the vaccination. These results were the final proof of high efficiency and safety of live poliomyelitis vaccine from the attenuated Sabin strains. Based on these results, A. Sabin and M. P. Chumakov suggested in 1960 the idea of poliomyelitis eradication using mass immunization of children with live vaccine. 72 million persons up to 20 years old were vaccinated in USSR in 1960 with a 5 times drop in the paralytic rate. 50-year-long use of live vaccine results in poliomyelitis eradication in almost all countries worldwide. More than 10 million children were rescued from the death and palsy. Poliomyelitis eradication in a few countries where it still exists depends not on medical services but is defined by the attitude of their leaders to fight

  8. Prolonging morbidity in rabid dogs by intrathecal injection of attenuated rabies vaccine.

    PubMed Central

    Baer, G M; Shaddock, J H; Williams, L W

    1975-01-01

    Dogs vaccinated intrathecally with attenuated rabies vaccine developed antibodies that were detected in the cerebrospinal fluid, blood, and brain; dogs similarly vaccinated but with an inactivated vaccine developed no antibodies in the brain. When the attenuated vaccine was administered to rabid dogs, a prolongation of the morbidity period was noted and, in some dogs, recovery from the disease. Rhesus monkeys died when administered any of the available attenuated vaccines intrathecally, and further studies with that species could not be undertaken. PMID:1095494

  9. Development of an acid-resistant Salmonella Typhi Ty21a attenuated vector for improved oral vaccine delivery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, T...

  10. Rational development of an attenuated recombinant cyprinid herpesvirus 3 vaccine using prokaryotic mutagenesis and in vivo bioluminescent imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyprinid herpesvirus 3 (CyHV-3) is causing severe economic losses worldwide in the carp industry, and a safe and efficacious attenuated vaccine compatible with mass vaccination is needed. We produced single deleted recombinants using prokaryotic mutagenesis. When producing a recombinant lacking open...

  11. Development of a live attenuated antigenic marker classical swine fever vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical Swine Fever, caused by Classical Swine Fever Virus (CSFV), is a highly contagious disease affecting swine worldwide. The two main strategies for disease control are prophylactic vaccination and non-vaccination “stamping out” policies. In a vaccination-to-live strategy, marker vaccines coul...

  12. Chikungunya vaccines in development

    PubMed Central

    Schwameis, Michael; Buchtele, Nina; Wadowski, Patricia Pia; Schoergenhofer, Christian; Jilma, Bernd

    2016-01-01

    ABSTRACT Chikungunya virus has become a global health threat, spreading to the industrial world of Europe and the Americas; no treatment or prophylactic vaccine is available. Since the late 1960s much effort has been put into the development of a vaccine, and several heterogeneous strategies have already been explored. Only two candidates have recently qualified to enter clinical phase II trials, a chikungunya virus-like particle-based vaccine and a recombinant live attenuated measles virus-vectored vaccine. This review focuses on the current status of vaccine development against chikungunya virus in humans and discusses the diversity of immunization strategies, results of recent human trials and promising vaccine candidates. PMID:26554522

  13. Dengue virus vaccine development.

    PubMed

    Yauch, Lauren E; Shresta, Sujan

    2014-01-01

    Dengue virus (DENV) is a significant cause of morbidity and mortality in tropical and subtropical regions, causing hundreds of millions of infections each year. Infections range from asymptomatic to a self-limited febrile illness, dengue fever (DF), to the life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). The expanding of the habitat of DENV-transmitting mosquitoes has resulted in dramatic increases in the number of cases over the past 50 years, and recent outbreaks have occurred in the United States. Developing a dengue vaccine is a global health priority. DENV vaccine development is challenging due to the existence of four serotypes of the virus (DENV1-4), which a vaccine must protect against. Additionally, the adaptive immune response to DENV may be both protective and pathogenic upon subsequent infection, and the precise features of protective versus pathogenic immune responses to DENV are unknown, complicating vaccine development. Numerous vaccine candidates, including live attenuated, inactivated, recombinant subunit, DNA, and viral vectored vaccines, are in various stages of clinical development, from preclinical to phase 3. This review will discuss the adaptive immune response to DENV, dengue vaccine challenges, animal models used to test dengue vaccine candidates, and historical and current dengue vaccine approaches.

  14. Cross-Protection against Marburg Virus Strains by Using a Live, Attenuated Recombinant Vaccine

    DTIC Science & Technology

    2006-10-01

    considered to have potential as a biological weapon. Recently, we reported the development of a promising attenuated, replication -competent vaccine against...MARV infections, we recently described the development of a promising new replication -competent vaccine against MARV based on recombinant vesicular...reported the development of a promising attenuated, replication -competent vaccine against MARV based on recombinant vesicular stomatitis virus (VSV

  15. Genetic engineering of attenuated malaria parasites for vaccination.

    PubMed

    Khan, Shahid M; Janse, Chris J; Kappe, Stefan H I; Mikolajczak, Sebastian A

    2012-12-01

    Vaccination with live-attenuated Plasmodium sporozoites that arrest in the liver can completely protect against a malaria infection both in animal models and in humans; this has provided the conceptual basis for the most promising, but also challenging, approach to develop an efficacious malaria vaccine. Advances in genetic manipulation of Plasmodium in conjunction with improved genomic and biological information has enabled new approaches to design genetically attenuated parasites (GAPs). In this review we discuss the principles in discovery and development of GAPs in preclinical models that are important in selecting GAP parasites for first-in-human clinical studies. Finally, we highlight the challenges in manufacture, formulation and delivery of a live-attenuated whole parasite malaria vaccine, as well as the further refinements that may be implemented in the next generation GAP vaccines.

  16. A novel live-attenuated vaccine candidate for mayaro Fever.

    PubMed

    Weise, William J; Hermance, Meghan E; Forrester, Naomi; Adams, A Paige; Langsjoen, Rose; Gorchakov, Rodion; Wang, Eryu; Alcorn, Maria D H; Tsetsarkin, Konstantin; Weaver, Scott C

    2014-08-01

    Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  17. A Novel Live-Attenuated Vaccine Candidate for Mayaro Fever

    PubMed Central

    Weise, William J.; Hermance, Meghan E.; Forrester, Naomi; Adams, A. Paige; Langsjoen, Rose; Gorchakov, Rodion; Wang, Eryu; Alcorn, Maria D. H.; Tsetsarkin, Konstantin; Weaver, Scott C.

    2014-01-01

    Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease. PMID:25101995

  18. Promises and pitfalls of live attenuated pneumococcal vaccines.

    PubMed

    Rosch, Jason W

    2014-01-01

    The pneumococcus is a remarkably adaptable pathogen whose disease manifestations range from mucosal surface infections such as acute otitis media and pneumonia to invasive infections such as sepsis and meningitis. Currently approved vaccines target the polysaccharide capsule, of which there are over 90 distinct serotypes, leading to rapid serotype replacement in vaccinated populations. Substantial progress has been made in the development of a universal pneumococcal vaccine, with efforts focused on broadly conserved and protective protein antigens. An area attracting considerable attention is the potential application of live attenuated vaccines to confer serotype-independent protection against mucosal and systemic infection. On the basis of recent work to understand the mucosal and systemic responses to nasal administration of pneumococci and to develop novel attenuation strategies, the prospect of a practical and protective live vaccine remains promising.

  19. Blockade of CTLA-4 promotes the development of effector CD8+ T lymphocytes and the therapeutic effect of vaccination with an attenuated protozoan expressing NY-ESO-1.

    PubMed

    Dos Santos, Luara Isabela; Galvão-Filho, Bruno; de Faria, Paula Cristina; Junqueira, Caroline; Dutra, Miriam Santos; Teixeira, Santuza Maria Ribeiro; Rodrigues, Maurício Martins; Ritter, Gerd; Bannard, Oliver; Fearon, Douglas Thomas; Antonelli, Lis Ribeiro; Gazzinelli, Ricardo Tostes

    2015-03-01

    The development of cancer immunotherapy has long been a challenge. Here, we report that prophylactic vaccination with a highly attenuated Trypanosoma cruzi strain expressing NY-ESO-1 (CL-14-NY-ESO-1) induces both effector memory and effector CD8(+) T lymphocytes that efficiently prevent tumor development. However, the therapeutic effect of such a vaccine is limited. We also demonstrate that blockade of Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) during vaccination enhances the frequency of NY-ESO-1-specific effector CD8(+) T cells producing IFN-γ and promotes lymphocyte migration to the tumor infiltrate. As a result, therapy with CL-14-NY-ESO-1 together with anti-CTLA-4 is highly effective in controlling the development of an established melanoma.

  20. Dengue 4 Vaccine Development

    DTIC Science & Technology

    1987-09-01

    CopU~1C FftE 0~AD( ) DENGUE 4 VACCINE DEVELOPMENT Lf 0, to ANNUAL AND FINAL REPORT0 by 0Nyven J. Marchette, Ph.D. September 1, 1987 (For the period 1... Dengue 4 Vaccine Development 12. PERSONAL AUTHOR(S) Nyven Marchette. Ph.D. 13a. TYPE OF REPORT T COVERED 114. DATE OF REPORT (Year, Month, Day) 15. PAGE...necessary and identi’fy by block number) FIELD GROUP SUB-GROUP Key words: Virus, arbovirus, dengue , dengue -4, vaccinej attenuation, immunity, RAI

  1. Mycoplasma gallisepticum: Control by live attenuated vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercially available attenuated strains of Mycoplasma gallisepticum (MG) are commonly used within the layer industry to control MG-induced mycoplasmosis. Among these are two live MG vaccines derived from the moderately pathogenic MG “chick F” strain. In the present study, the commercially availa...

  2. Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery

    PubMed Central

    Feuille, Catherine M.; Starke, Carly Elizabeth C.; Bhagwat, Arvind A.; Stibitz, Scott; Kopecko, Dennis J.

    2016-01-01

    The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain. PMID:27673328

  3. Brunenders: a partially attenuated historic poliovirus type I vaccine strain.

    PubMed

    Sanders, Barbara P; Liu, Ying; Brandjes, Alies; van Hoek, Vladimir; de Los Rios Oakes, Isabel; Lewis, John; Wimmer, Eckard; Custers, Jerome H H V; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2015-09-01

    Brunenders, a type I poliovirus (PV) strain, was developed in 1952 by J. F. Enders and colleagues through serial in vitro passaging of the parental Brunhilde strain, and was reported to display partial neuroattenuation in monkeys. This phenotype of attenuation encouraged two vaccine manufacturers to adopt Brunenders as the type I component for their inactivated poliovirus vaccines (IPVs) in the 1950s, although today no licensed IPV vaccine contains Brunenders. Here we confirmed, in a transgenic mouse model, the report of Enders on the reduced neurovirulence of Brunenders. Although dramatically neuroattenuated relative to WT PV strains, Brunenders remains more virulent than the attenuated oral vaccine strain, Sabin 1. Importantly, the neuroattenuation of Brunenders does not affect in vitro growth kinetics and in vitro antigenicity, which were similar to those of Mahoney, the conventional type I IPV vaccine strain. We showed, by full nucleotide sequencing, that Brunhilde and Brunenders differ at 31 nucleotides, eight of which lead to amino acid changes, all located in the capsid. Upon exchanging the Brunenders capsid sequence with that of the Mahoney capsid, WT neurovirulence was regained in vivo, suggesting a role for the capsid mutations in Brunenders attenuation. To date, as polio eradication draws closer, the switch to using attenuated strains for IPV is actively being pursued. Brunenders preceded this novel strategy as a partially attenuated IPV strain, accompanied by decades of successful use in the field. Providing data on the attenuation of Brunenders may be of value in the further construction of attenuated PV strains to support the grand pursuit of the global eradication of poliomyelitis.

  4. Development of a dual-protective live attenuated vaccine against H5N1 and H9N2 avian influenza viruses by modifying the NS1 gene.

    PubMed

    Choi, Eun-hye; Song, Min-Suk; Park, Su-Jin; Pascua, Philippe Noriel Q; Baek, Yun Hee; Kwon, Hyeok-il; Kim, Eun-Ha; Kim, Semi; Jang, Hyung-Kwan; Poo, Haryoung; Kim, Chul-Joong; Choi, Young Ki

    2015-07-01

    An increasing number of outbreaks of avian influenza H5N1 and H9N2 viruses in poultry have caused serious economic losses and raised concerns for human health due to the risk of zoonotic transmission. However, licensed H5N1 and H9N2 vaccines for animals and humans have not been developed. Thus, to develop a dual H5N1 and H9N2 live-attenuated influenza vaccine (LAIV), the HA and NA genes from a virulent mouse-adapted avian H5N2 (A/WB/Korea/ma81/06) virus and a recently isolated chicken H9N2 (A/CK/Korea/116/06) virus, respectively, were introduced into the A/Puerto Rico/8/34 backbone expressing truncated NS1 proteins (NS1-73, NS1-86, NS1-101, NS1-122) but still possessing a full-length NS gene. Two H5N2/NS1-LAIV viruses (H5N2/NS1-86 and H5N2/NS1-101) were highly attenuated compared with the full-length and remaining H5N2/NS-LAIV viruses in a mouse model. Furthermore, viruses containing NS1 modifications were found to induce more IFN-β activation than viruses with full-length NS1 proteins and were correspondingly attenuated in mice. Intranasal vaccination with a single dose (10(4.0) PFU/ml) of these viruses completely protected mice from a lethal challenge with the homologous A/WB/Korea/ma81/06 (H5N2), heterologous highly pathogenic A/EM/Korea/W149/06 (H5N1), and heterosubtypic highly virulent mouse-adapted H9N2 viruses. This study clearly demonstrates that the modified H5N2/NS1-LAIV viruses attenuated through the introduction of mutations in the NS1 coding region display characteristics that are desirable for live attenuated vaccines and hold potential as vaccine candidates for mammalian hosts.

  5. Herpes Simplex Vaccines: Prospects of Live-attenuated HSV Vaccines to Combat Genital and Ocular infections.

    PubMed

    Stanfield, Brent; Kousoulas, Konstantin Gus

    2015-09-01

    Herpes simplex virus type-1 (HSV-1) and its closely related type-2 (HSV-2) viruses cause important clinical manifestations in humans including acute ocular disease and genital infections. These viruses establish latency in the trigeminal ganglionic and dorsal root neurons, respectively. Both viruses are widespread among humans and can frequently reactivate from latency causing disease. Currently, there are no vaccines available against herpes simplex viral infections. However, a number of promising vaccine approaches are being explored in pre-clinical investigations with few progressing to early phase clinical trials. Consensus research findings suggest that robust humoral and cellular immune responses may partially control the frequency of reactivation episodes and reduce clinical symptoms. Live-attenuated viral vaccines have long been considered as a viable option for generating robust and protective immune responses against viral pathogens. Varicella zoster virus (VZV) belongs to the same alphaherpesvirus subfamily with herpes simplex viruses. A live-attenuated VZV vaccine has been extensively used in a prophylactic and therapeutic approach to combat primary and recurrent VZV infection indicating that a similar vaccine approach may be feasible for HSVs. In this review, we summarize pre-clinical approaches to HSV vaccine development and current efforts to test certain vaccine approaches in human clinical trials. Also, we discuss the potential advantages of using a safe, live-attenuated HSV-1 vaccine strain to protect against both HSV-1 and HSV-2 infections.

  6. Rhodococcus equi (Prescottella equi) vaccines; the future of vaccine development.

    PubMed

    Giles, C; Vanniasinkam, T; Ndi, S; Barton, M D

    2015-09-01

    For decades researchers have been targeting prevention of Rhodococcus equi (Rhodococcus hoagui/Prescottella equi) by vaccination and the horse breeding industry has supported the ongoing efforts by researchers to develop a safe and cost effective vaccine to prevent disease in foals. Traditional vaccines including live, killed and attenuated (physical and chemical) vaccines have proved to be ineffective and more modern molecular-based vaccines including the DNA plasmid, genetically attenuated and subunit vaccines have provided inadequate protection of foals. Newer, bacterial vector vaccines have recently shown promise for R. equi in the mouse model. This article describes the findings of key research in R. equi vaccine development and looks at alternative methods that may potentially be utilised.

  7. Safety of a live attenuated Erysipelothrix rhusiopathiae vaccine for swine.

    PubMed

    Neumann, Eric J; Grinberg, Alex; Bonistalli, Kathryn N; Mack, Hamish J; Lehrbach, Philip R; Gibson, Nicole

    2009-03-30

    Infection with Erysipelothrix rhusiopathiae has a significant economic impact on pig production systems worldwide. Both inactivated and attenuated vaccines are available to prevent development of clinical signs of swine erysipelas. The ability of a live attenuated E. rhusiopathiae strain to become persistently established in pigs after intranasal exposure and its potential to cause clinical signs consistent with swine erysipelas after being administered directly into the nasopharynx of healthy pigs was evaluated. Five, E. rhusiopathiae-negative pigs were vaccinated by deep intranasal inoculation then followed for 14 days. Nasal swabs were collected daily for 5 days and clinical observations were made daily for 14 days post-vaccination. Nasal swabs were cultured for E. rhusiopathiae with the intent of back-passaging any recovered organisms into subsequent replicates. No organism was recovered from nasal swabs in the first vaccination replicate. A second replicate including 10 pigs was initiated and followed in an identical manner to that described above. Again, no E. rhusiopathiae was recovered from any pigs. No pigs in either replicate showed any signs of clinical swine erysipelas. The live attenuated E. rhusiopathiae strain evaluated in this study did not appear to become persistently established in pigs post-vaccination, did not cause any local or systemic signs consistent with swine erysipelas, and was therefore unlikely to revert to a virulent state when used in a field setting.

  8. Live Attenuated Recombinant Vaccine Protects Nonhuman Primates Against Ebola and Marburg Viruses

    DTIC Science & Technology

    2005-06-05

    Marburg virus (MARV). Here, we developed replication -competent vaccines against EBOV and MARV based on attenuated recombinant vesicular stomatitis...No evidence of EBOV or MARV replication was detected in any of the protected animals after challenge. Our data suggest that these vaccine...number of efforts have focused on developing vaccines against MARV. Alphavirus replicons expressing MARV proteins protected cynomolgus monkeys from

  9. [Live attenuated and inactivated influenza vaccines: data from direct comparative studies].

    PubMed

    Kashirina, O S; Vasil'ev, Iu M

    2014-01-01

    Comparative evaluation of live attenuated and inactivated influenza vaccines based on data from direct comparative studies is necessary for ensuring the most effective and safe vaccination against influenza. Analysis of direct comparative preclinical and clinical studies of inactivated and live cold-adapted (ca) influenza vaccines showed that published data are inconsistent and limited for some population groups. Live ca vaccines may be promising as an alternative or addition to inactivated vaccines especially for mass vaccination against influenza in children as well as in the elderly when combined with inactivated vaccines. Further studies of inactivated and live ca influenza vaccines in direct comparative studies that control the administration route and vaccine strain production as well as development and confirmation of objective criteria of live attenuated influenza vaccine effectiveness evaluation are necessary.

  10. Inactivated polio vaccine development for technology transfer using attenuated Sabin poliovirus strains to shift from Salk-IPV to Sabin-IPV.

    PubMed

    Bakker, Wilfried A M; Thomassen, Yvonne E; van't Oever, Aart G; Westdijk, Janny; van Oijen, Monique G C T; Sundermann, Lars C; van't Veld, Peter; Sleeman, Eelco; van Nimwegen, Fred W; Hamidi, Ahd; Kersten, Gideon F A; van den Heuvel, Nico; Hendriks, Jan T; van der Pol, Leo A

    2011-09-22

    Industrial-scale inactivated polio vaccine (IPV) production dates back to the 1960s when at the Rijks Instituut voor de Volksgezondheid (RIV) in Bilthoven a process was developed based on micro-carrier technology and primary monkey kidney cells. This technology was freely shared with several pharmaceutical companies and institutes worldwide. In this contribution, the history of one of the first cell-culture based large-scale biological production processes is summarized. Also, recent developments and the anticipated upcoming shift from regular IPV to Sabin-IPV are presented. Responding to a call by the World Health Organization (WHO) for new polio vaccines, the development of Sabin-IPV was continued, after demonstrating proof of principle in the 1990s, at the Netherlands Vaccine Institute (NVI). Development of Sabin-IPV plays an important role in the WHO polio eradication strategy as biocontainment will be critical in the post-OPV cessation period. The use of attenuated Sabin strains instead of wild-type Salk polio strains will provide additional safety during vaccine production. Initially, the Sabin-IPV production process will be based on the scale-down model of the current, and well-established, Salk-IPV process. In parallel to clinical trial material production, process development, optimization and formulation research is being carried out to further optimize the process and reduce cost per dose. Also, results will be shown from large-scale (to prepare for future technology transfer) generation of Master- and Working virus seedlots, and clinical trial material (for phase I studies) production. Finally, the planned technology transfer to vaccine manufacturers in low and middle-income countries is discussed.

  11. Clinical evaluation strategies for a live attenuated tetravalent dengue vaccine.

    PubMed

    Precioso, Alexander Roberto; Palacios, Ricardo; Thomé, Beatriz; Mondini, Gabriella; Braga, Patrícia; Kalil, Jorge

    2015-12-10

    Butantan Institute is a public Brazilian biomedical research-manufacturer center affiliated to the São Paulo State Secretary of Health. Currently, Butantan is one of the main public producers of vaccines, antivenoms, and antitoxins in Latin America. The partnership between Butantan and the National Institutes of Health (NIH) of the United Sates has been one of the longest and most successful partnerships in the development and manufacturing of new vaccines. Recently, Butantan Institute has developed and manufactured a lyophilized tetravalent live attenuated dengue vaccine with the four dengue viruses attenuated and licensed from the Laboratory of Infectious Diseases at The National Institutes of Allergy and Infectious Diseases (LID/NIAID/NIH). The objective of this paper is to describe the clinical evaluation strategies of a live attenuated tetravalent dengue vaccine (Butantan-DV) developed and manufactured by Butantan Institute. These clinical strategies will be used to evaluate the Butantan-DV Phase III trial to support the Butantan-DV licensure for protection against any symptomatic dengue caused by any serotype in people aged 2 to 59 years.

  12. The efficacy of an inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis on follicular development and ovulation responses in crossbred buffaloes.

    PubMed

    Liu, Qing; Han, Li; Rehman, Zia Ur; Dan, Xingang; Liu, Xiaoran; Bhattarai, Dinesh; Yang, Liguo

    2016-09-01

    The aim of this study was to evaluate the efficacy of an inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis on follicular development and ovulation responses in crossbred buffaloes. A total of 158 crossbred buffaloes divided into four groups and were intramuscularly injected with 1×10(10) (T1, n=41), 1×10(9) (T2, n=37), 1×10(8) (T3, n=37) or 0 (C, n=43) CFU/ml bacteria delivered inhibin vaccine in 10ml PBS on day 0 and 14, respectively. All animals were administered with 1000 IU PMSG on day 28, 0.5mg PGF2α on day 30 and 200μg GnRH on day 32. The results showed buffaloes immunized with the bacteria delivered inhibin vaccine had significantly higher titers of anti-inhibin IgG antibody than control group (P<0.01). The number and diameter of large follicles (≥10mm) as well as ovulatory follicles in group T1 was significantly greater than group C (P<0.05). The growth speed of dominant follicles in group T1 was significantly faster than groups T3 and C (P<0.05), resulting in a greater conception rate in buffaloes with positive antibodies. These results demonstrate that immunization with the bacterial delivered inhibin vaccine, coupled with the estrus synchronization protocol, could be used as an alternative approach to improve fertility in crossbred buffaloes.

  13. Development of one-step real-time PCR assay for titrating trivalent live attenuated influenza vaccines

    PubMed Central

    Zang, Yang; Du, Dongchuan; Ge, Peng; Xu, Yongqing; Liu, Xintao; Zhang, Yan; Su, Weiheng; Kiseleva, Irina; Rudenko, Larisa; Xu, Fei; Kong, Wei; Jiang, Chunlai

    2014-01-01

    Traditionally, infectivity of a trivalent live attenuated influenza vaccines (LAIVs) is titrated by determining the 50% egg infectious dose assay (EID50) or plaque forming units (PFU), which requires specific monoclonal antibodies to neutralize 2 strains while estimating the titer of the non-neutralized strain. Compared to this time-consuming, laborious, subjective and variable process, reverse transcription-quantitative real-time PCR (RT-qPCR) technology has advantages of rapidity, sensitivity, reproducibility and reduced contamination, thus has been applied widely for detecting pathogens and measuring viral titers. In this study, the critical harvest time was determined to be 18 h post-infection (hpi) for type A influenza and 12 hpi for type B influenza, but no significant difference between titers at 12 hpi and 18 hpi for the type B strain was observed. In conclusion, trivalent LAIVs can be titrated simultaneously within 24 h by this one-step RT-qPCR assay, which yielded titers comparable to those obtained by the traditional EID50 assay. Therefore, the RT-qPCR assay may be used as a highly specific, sensitive, precise and rapid alternative to the EID50 assay for titering LAIVs. PMID:25483696

  14. Attenuated and vectored vaccines protect nonhuman primates against Chikungunya virus

    PubMed Central

    Ljungberg, Karl; Kümmerer, Beate M.; Gosse, Leslie; Dereuddre-Bosquet, Nathalie; Tchitchek, Nicolas; Hallengärd, David; García-Arriaza, Juan; Meinke, Andreas; Esteban, Mariano; Merits, Andres

    2017-01-01

    Chikungunya virus (CHIKV) is rapidly spreading across the globe, and millions are infected. Morbidity due to this virus is a serious threat to public health, but at present, there is no vaccine against this debilitating disease. We have recently developed a number of vaccine candidates, and here we have evaluated 3 of them in a nonhuman primate model. A single immunization with an attenuated strain of CHIKV (Δ5nsP3), a homologous prime-boost immunization with a DNA-launched RNA replicon encoding CHIKV envelope proteins (DREP-E), and a DREP-E prime followed by a recombinant modified vaccinia virus Ankara encoding CHIKV capsid and envelope (MVA-CE) boost all induced protection against WT CHIKV infection. The attenuated Δ5nsP3 virus proved to be safe and did not show any clinical signs typically associated with WT CHIKV infections such as fever, skin rash, lymphopenia, or joint swelling. These vaccines are based on an East/Central/South African strain of Indian Ocean lineage, but they also generated neutralizing antibodies against an isolate of the Asian genotype that now is rapidly spreading across the Americas. These results form the basis for clinical development of an efficacious CHIKV vaccine that generates both humoral and cellular immunity with long-term immunological memory. PMID:28352649

  15. Characterization of attenuated Theileria annulata vaccines from Spain and the Sudan.

    PubMed

    Gubbels, M J; Viseras, J; Habela, M A; Jongejan, F

    2000-01-01

    Theileriosis caused by Theileria annulata can be effectively prevented by vaccination with attenuated, cultured schizonts. Although these attenuated vaccines have been applied for a long time, not much is known about the fate of the vaccine strain in the field. Here, two experimental Spanish vaccine strains originating in Cádiz and Cáceres, and one Sudanese strain are studied to address the development of a carrier status and the infectivity for Hyalomma ticks. Moreover, the heterogeneity of the merozoite surface protein, Tams1, was analyzed in search for an attenuation marker. Using the sensitive reverse line blot (RLB) hybridization, the development of a low level carrier status was demonstrated in the Cáceres and Sudanese line vaccinated calves. Although no signal was detected in the Cádiz line vaccinated calves, seroconversion against the schizont stage was observed, as it was in all other calves. The experimental transmission of T. annulata by Hyalomma ticks to naïve calves was unsuccessful for all cell line inoculated calves. Tams1 heterogeneity indicated a clonal selection of parasites during the process of attenuation, but the Tams1 sequence itself has no connection with the attenuation status. In conclusion, a carrier status develops in attenuated schizont culture vaccinated calves, but is not infective for Hyalomma ticks. Based on these data, the risk for spread of the vaccine strains in the field may be very low.

  16. Clinical vaccine development

    PubMed Central

    2015-01-01

    Vaccination is regarded as one of the biggest triumphs in the history of medicine. We are living in the most successful period of vaccine development. The accumulation of multidisciplinary knowledge and the investment of massive funding have enabled the development of vaccines against many infectious diseases as well as other diseases including malignant tumors. The paradigm of clinical vaccine evaluation and licensure has also been modernized based on scientific improvements and historical experience. However, there remain a number of hurdles to overcome. Continuous efforts are focused on increasing the efficacy and reducing the risks related to vaccine use. Cutting-edge knowledge about immunology and microbiology is being rapidly translated to vaccine development. Thus, physicians and others involved in the clinical development of vaccines should have sufficient understanding of the recent developmental trends in vaccination and the diseases of interest. PMID:25648742

  17. Development of a recombinant epsilon toxoid vaccine against enterotoxemia and its use as a combination vaccine with live attenuated sheep pox virus against enterotoxemia and sheep pox.

    PubMed

    Chandran, Dev; Naidu, Sureddi Satyam; Sugumar, Parthasarathy; Rani, Gudavalli Sudha; Vijayan, Shahana Pallichera; Mathur, Deepika; Garg, Lalit C; Srinivasan, Villuppanoor Alwar

    2010-06-01

    Sheep pox and enterotoxemia are important diseases of sheep, and these diseases cause severe economic losses to sheep farmers. The present study was undertaken to evaluate the potential of formaldehyde-inactivated recombinant epsilon toxin as a vaccine candidate. The potency of the recombinant epsilon toxoid with aluminum hydroxide as an adjuvant in sheep was determined. Vaccinated sheep were protected against enterotoxemia, with potency values of >5 IU being protective. Further, the use of this construct in a combination vaccine against sheep pox resulted in the sheep being protected against both sheep pox and enterotoxemia.

  18. Gene-deleted live-attenuated Trypanosoma cruzi parasites as vaccines to protect against Chagas disease.

    PubMed

    Sánchez-Valdéz, Fernando J; Pérez Brandán, Cecilia; Ferreira, Arturo; Basombrío, Miguel Ángel

    2015-05-01

    Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. This illness is now becoming global, mainly due to congenital transmission, and so far, there are no prophylactic or therapeutic vaccines available to either prevent or treat Chagas disease. Therefore, different approaches aimed at identifying new protective immunogens are urgently needed. Live vaccines are likely to be more efficient in inducing protection, but safety issues linked with their use have been raised. The development of improved protozoan genetic manipulation tools and genomic and biological information has helped to increase the safety of live vaccines. These advances have generated a renewed interest in the use of genetically attenuated parasites as vaccines against Chagas disease. This review discusses the protective capacity of genetically attenuated parasite vaccines and the challenges and perspectives for the development of an effective whole-parasite Chagas disease vaccine.

  19. Vaccine development using recombinant DNA technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccines induce an immune response in the host that subsequently recognizes infectious agents and helps fight off the disease; vaccines must do this without causing the disease. This paper reviews the development of recombinant DNA technologies as a means of providing new ways for attenuating diseas...

  20. Live attenuated vaccines: Historical successes and current challenges

    SciTech Connect

    Minor, Philip D.

    2015-05-15

    Live attenuated vaccines against human viral diseases have been amongst the most successful cost effective interventions in medical history. Smallpox was declared eradicated in 1980; poliomyelitis is nearing global eradication and measles has been controlled in most parts of the world. Vaccines function well for acute diseases such as these but chronic infections such as HIV are more challenging for reasons of both likely safety and probable efficacy. The derivation of the vaccines used has in general not been purely rational except in the sense that it has involved careful clinical trials of candidates and subsequent careful follow up in clinical use; the identification of the candidates is reviewed. - Highlights: • Live vaccines against human diseases caused by viruses have been very successful. • They have been developed by empirical clinical studies and problems identified in later use. • It can be difficult to balance ability to cause disease and ability to immunise for a strain. • There is currently no reliable basis for predicting success from pure virological studies. • Vaccinia, which eradicated smallpox, is the paradigm for all successes and issues.

  1. New Approaches to Attenuated Hepatitis A Vaccine Development: Cloning and Sequencing of Cell-Culture Adapted Viral cDNA.

    DTIC Science & Technology

    1986-10-13

    A Vaccine, Molecular Cloning & Hybridization 06 13 Strain Differences 06 03 19. ABSTRACT ("n on reverse if necessary and identify by block number) N...immediate objective of work supported under this contract has been the molecular cloning of RNA from a variant of HM175 virus which is derived from the...dideoxynucleotide sequencing technique is currently being explored as a means of specific strain identification. RESEARCH PROGRESS 1. Molecular Cloning and

  2. A review of immunogenicity and tolerability of live attenuated Hepatitis A vaccine in children

    PubMed Central

    Rao, Sameer; Mao, J. S.; Motlekar, Salman; Fangcheng, Zhuang; Kadhe, Ganesh

    2016-01-01

    ABSTRACT Changing epidemiology of Hepatitis A virus (HAV) has led to an increased susceptibility of adolescents and adults to the infection. Vaccination can remarkably reduce the incidence and associated morbidity of HAV infection. This review is focused on the safety and efficacy of H2 strain derived live attenuated Hepatitis A vaccine. We found the vaccine to be highly immunogenic with minimal or negligible safety issues. Moreover, a single dose of live attenuated vaccine persists a long term immune response and can be a preferred option for developing countries. In 2014, Indian Academy of Paediatrics (IAP) also updated their recommendations for H2 vaccine as a single dose as against the previous 2 dose schedule. A focused approach to include the vaccine in national immunization program should be explored. PMID:27532370

  3. Novel vaccine against Venezuelan equine encephalitis combines advantages of DNA immunization and a live attenuated vaccine.

    PubMed

    Tretyakova, Irina; Lukashevich, Igor S; Glass, Pamela; Wang, Eryu; Weaver, Scott; Pushko, Peter

    2013-02-04

    DNA vaccines combine remarkable genetic and chemical stability with proven safety and efficacy in animal models, while remaining less immunogenic in humans. In contrast, live-attenuated vaccines have the advantage of inducing rapid, robust, long-term immunity after a single-dose vaccination. Here we describe novel iDNA vaccine technology that is based on an infectious DNA platform and combines advantages of DNA and live attenuated vaccines. We applied this technology for vaccination against infection with Venezuelan equine encephalitis virus (VEEV), an alphavirus from the Togaviridae family. The iDNA vaccine is based on transcription of the full-length genomic RNA of the TC-83 live-attenuated virus from plasmid DNA in vivo. The in vivo-generated viral RNA initiates limited replication of the vaccine virus, which in turn leads to efficient immunization. This technology allows the plasmid DNA to launch a live-attenuated vaccine in vitro or in vivo. Less than 10 ng of pTC83 iDNA encoding the full-length genomic RNA of the TC-83 vaccine strain initiated replication of the vaccine virus in vitro. In order to evaluate this approach in vivo, BALB/c mice were vaccinated with a single dose of pTC83 iDNA. After vaccination, all mice seroconverted with no adverse reactions. Four weeks after immunization, animals were challenged with the lethal epidemic strain of VEEV. All iDNA-vaccinated mice were protected from fatal disease, while all unvaccinated controls succumbed to infection and died. To our knowledge, this is the first example of launching a clinical live-attenuated vaccine from recombinant plasmid DNA in vivo.

  4. New Approaches to Attenuated Hepatitis a Vaccine Development: Cloning and Sequencing of Cell-Culture Adapted Viral cDNA.

    DTIC Science & Technology

    1987-10-13

    reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Hepatitis A Vaccine, Molecular Cloning and Hybridization, 06 13 Strain Differences...cells. Molecular cloning of p16 HM175 virus cDNA. cDNA clones were derived from p16 HM175 virus RNA by cloning cDNA-RNA hybrid molecules into the Pstl... molecular cloning . Clones derived from cDNA synthesized with oligo-dT_12 18 as primer were nearly always restricted to the 3’ terminus of the genome, while

  5. Characterization of an intracellular ATP assay for evaluating the viability of live attenuated mycobacterial vaccine preparations.

    PubMed

    Kolibab, Kristopher; Derrick, Steven C; Jacobs, William R; Morris, Sheldon L

    2012-09-01

    The viability of BCG vaccine has traditionally been monitored using a colony-forming unit (CFU) assay. Despite its widespread use, results from the CFU assay can be highly variable because of the characteristic clumping of mycobacteria, their requirement for complex growth media, and the three week incubation period needed to cultivate slow-growing mycobacteria. In this study, we evaluated whether an ATP luminescence assay (which measures intracellular ATP content) could be used to rapidly estimate the viability of lyophilized and/or frozen preparations of six different BCG vaccine preparations - Danish, Tokyo, Russia, Brazil, Tice, and Pasteur - and two live attenuated mycobacterial vaccine candidates - a ΔlysAΔpanCD M. tuberculosis strain and a ΔmmaA4 BCG vaccine mutant. For every vaccine tested, a significant correlation was observed between intracellular ATP concentrations and the number of viable attenuated bacilli. However, the extractable intracellular ATP levels detected per cell among the different live vaccines varied suggesting that validated ATP luminescence assays with specific appropriate standards must be developed for each individual live attenuated vaccine preparation. Overall, these data indicate that the ATP luminescence assay is a rapid, sensitive, and reliable alternative method for quantifying the viability of varying live attenuated mycobacterial vaccine preparations.

  6. CHIMERIC SINDBIS/EASTERN EQUINE ENCEPHALITIS VACCINE CANDIDATES ARE HIGHLY ATTENUATED AND IMMUNOGENIC IN MICE

    PubMed Central

    Wang, Eryu; Petrakova, Olga; Adams, A. Paige; Aguilar, Patricia V.; Kang, Wenli; Paessler, Slobodan; Volk, Sara M.; Frolov, Ilya; Weaver, Scott C.

    2007-01-01

    We developed chimeric Sindbis (SINV)/Eastern equine encephalitis (EEEV) viruses and investigated their potential for use as live virus vaccines against EEEV. One vaccine candidate contained structural protein genes from a typical North American EEEV strain, while the other had structural proteins from a naturally attenuated Brazilian isolate. Both chimeric viruses replicated efficiently in mammalian and mosquito cell cultures and were highly attenuated in mice. Vaccinated mice did not develop detectable disease or viremia, but developed high titers of neutralizing antibodies. Upon challenge with EEEV, mice vaccinated with >104PFU of the chimeric viruses were completely protected from disease. These findings support the potential use of these SIN/EEEV chimeras as safe and effective vaccines. PMID:17904699

  7. Development of a High-Yield Live Attenuated H7N9 Influenza Virus Vaccine That Provides Protection against Homologous and Heterologous H7 Wild-Type Viruses in Ferrets

    PubMed Central

    Baz, Mariana; Lu, Janine; Paskel, Myeisha; Santos, Celia; Subbarao, Kanta; Jin, Hong; Matsuoka, Yumiko

    2014-01-01

    ABSTRACT Live attenuated H7N9 influenza vaccine viruses that possess the hemagglutinin (HA) and neuraminidase (NA) gene segments from the newly emerged wild-type (wt) A/Anhui/1/2013 (H7N9) and six internal protein gene segments from the cold-adapted influenza virus A/Ann Arbor/6/60 (AA ca) were generated by reverse genetics. The reassortant virus containing the original wt A/Anhui/1/2013 HA and NA sequences replicated poorly in eggs. Multiple variants with amino acid substitutions in the HA head domain that improved viral growth were identified by viral passage in eggs and MDCK cells. The selected vaccine virus containing two amino acid changes (N133D/G198E) in the HA improved viral titer by more than 10-fold (reached a titer of 108.6 fluorescent focus units/ml) without affecting viral antigenicity. Introduction of these amino acid changes into an H7N9 PR8 reassortant virus also significantly improved viral titers and HA protein yield in eggs. The H7N9 ca vaccine virus was immunogenic in ferrets. A single dose of vaccine conferred complete protection of ferrets from homologous wt A/Anhui/1/2013 (H7N9) and nearly complete protection from heterologous wt A/Netherlands/219/2003 (H7N7) challenge infection. Therefore, this H7N9 live attenuated influenza vaccine (LAIV) candidate has been selected for vaccine manufacture and clinical evaluation to protect humans from wt H7N9 virus infection. IMPORTANCE In response to the recent avian H7N9 influenza virus infection in humans, we developed a live attenuated H7N9 influenza vaccine (LAIV) with two amino acid substitutions in the viral HA protein that improved vaccine yield by 10-fold in chicken embryonated eggs, the substrate for vaccine manufacture. The two amino acids also improved the antigen yield for inactivated H7N9 vaccines, demonstrating that this finding could great facilitate the efficiency of H7N9 vaccine manufacture. The candidate H7N9 LAIV was immunogenic and protected ferrets against homologous and heterologous

  8. Ricin vaccine development.

    PubMed

    Smallshaw, Joan E; Vitetta, Ellen S

    2012-01-01

    In this chapter we discuss vaccines to protect against the highly toxic plant-derived toxin, ricin. Due to its prevalence, ease of use, and stability it has been used in sporadic incidents of espionage. There is also concern that it will be used as an agent of bioterrorism. As a result there has been a great deal of interest in developing a safe vaccine or antidote to protect humans, and in particular soldiers and first responders. Although multiple types of vaccines have been tested, at this time two recombinant vaccines are the leading candidates for the national vaccine stockpile. In terms of passive post-exposure protection, monoclonal neutralizing antibodies that passively protect animals are also under development. These vaccines and antibodies are discussed in the context of the toxicity and structure of ricin.

  9. Live attenuated varicella-zoster vaccine in hematopoietic stem cell transplantation recipients.

    PubMed

    Issa, Nicolas C; Marty, Francisco M; Leblebjian, Houry; Galar, Alicia; Shea, Margaret M; Antin, Joseph H; Soiffer, Robert J; Baden, Lindsey R

    2014-02-01

    Hematopoietic stem cell transplantation (HSCT) recipients are at risk for varicella-zoster virus (VZV) reactivation. Vaccination may help restore VZV immunity; however, the available live attenuated VZV vaccine (Zostavax) is contraindicated in immunocompromised hosts. We report our experience with using a single dose of VZV vaccine in 110 adult autologous and allogeneic HSCT recipients who were about 2 years after transplantation, free of graft-versus-host disease, and not receiving immunosuppression. One hundred eight vaccine recipients (98.2%) had no clinically apparent adverse events with a median follow-up period of 9.5 months (interquartile range, 6 to 16; range, 2 to 28). Two vaccine recipients (1.8%) developed a skin rash (one zoster-like rash with associated pain, one varicella-like) within 42 days post-vaccination that resolved with antiviral therapy. We could not confirm if these rashes were due to vaccine (Oka) or wild-type VZV. No other possible cases of VZV reactivation have occurred with about 1178 months of follow-up. Live attenuated zoster vaccine appears generally safe in this population when vaccinated as noted; the overall vaccination risk needs to be weighed against the risk of wild-type VZV disease in this high-risk population.

  10. The Case for Live Attenuated Vaccines against the Neglected Zoonotic Diseases Brucellosis and Bovine Tuberculosis

    PubMed Central

    Pandey, Aseem; Cabello, Ana; Akoolo, Lavoisier; Rice-Ficht, Allison; Arenas-Gamboa, Angela; McMurray, David; Ficht, Thomas A.; de Figueiredo, Paul

    2016-01-01

    Vaccination of humans and animals with live attenuated organisms has proven to be an effective means of combatting some important infectious diseases. In fact, the 20th century witnessed tremendous improvements in human and animal health worldwide as a consequence of large-scale vaccination programs with live attenuated vaccines (LAVs). Here, we use the neglected zoonotic diseases brucellosis and bovine tuberculosis (BTb) caused by Brucella spp. and Mycobacterium bovis (M. bovis), respectively, as comparative models to outline the merits of LAV platforms with emphasis on molecular strategies that have been pursued to generate LAVs with enhanced vaccine safety and efficacy profiles. Finally, we discuss the prospects of LAV platforms in the fight against brucellosis and BTb and outline new avenues for future research towards developing effective vaccines using LAV platforms. PMID:27537413

  11. Influenza vaccination with live-attenuated and inactivated virus-vaccines during an outbreak of disease.

    PubMed Central

    Rocchi, G.; Ragona, G.; Piga, C.; Pelosio, A.; Volpi, A.; Vella, S.; Legniti, N.; de Felici, A.

    1979-01-01

    Immunization procedures with live attenuated and inactivated vaccines were carried out on a group of young recruits at the beginning of an outbreak of infection due to an A/Victoria/3/75-related virus strain, which occurred in February 1977 in a military camp. A retrospective investigation on protection from clinical influenza was then performed in order to investigate whether immunization with live virus vaccines, administered at the beginning of an epidemic, could provide early protection from the disease. In the course of the two weeks following vaccination, laboratory-confirmed clinical influenza cases occurred in 4 subjects among the 110 volunteers of the control group which received placebo, and in 8, 7 and 4 subjects respectively of the 3 groups of about 125 individuals, each of which received one of the following vaccine preparations: (a), live attenuated A/Victoria/3/75 influenza virus oral vaccine, grown on chick embryo kidney culture; (b), live attenuated nasal vaccine, a recombinant of A/Puerto Rico/8/34 with A/Victoria/3/75 virus; and (c), inactivated A/Victoria/3/75 virus intramuscular vaccine. These data do not support the hypothesis that, during an epidemic of infection, early protection from clinical influenza can be achieved through immunization with live attenuated or inactivated influenza virus vaccines, in spite of the high immunizing capability of the vaccine preparations. PMID:512351

  12. A vaccine candidate for eastern equine encephalitis virus based on IRES-mediated attenuation

    PubMed Central

    Pandya, Jyotsna; Gorchakov, Rodion; Wang, Eryu; Leal, Grace; Weaver, Scott C.

    2012-01-01

    To develop an effective vaccine against eastern equine encephalitis (EEE), we engineered a recombinant EEE virus (EEEV) that was attenuated and capable of replicating only in vertebrate cells, an important safety feature for live vaccines against mosquito-borne viruses. The subgenomic promoter was inactivated with 13 synonymous mutations and expression of the EEEV structural proteins was placed under the control of an internal ribosomal entry site (IRES) derived from encephalomyocarditis virus (EMCV). We tested this vaccine candidate for virulence, viremia and efficacy in the murine model. A single subcutaneous immunization with 104 infectious units protected 100% of mice against intraperitoneal challenge with a highly virulent North American EEEV strain. None of the mice developed any signs of disease or viremia after immunization or following challenge. Our findings suggest that the IRES-based attenuation approach can be used to develop a safe and effective vaccine against EEE and other alphaviral diseases. PMID:22222869

  13. A vaccine candidate for eastern equine encephalitis virus based on IRES-mediated attenuation.

    PubMed

    Pandya, Jyotsna; Gorchakov, Rodion; Wang, Eryu; Leal, Grace; Weaver, Scott C

    2012-02-08

    To develop an effective vaccine against eastern equine encephalitis (EEE), we engineered a recombinant EEE virus (EEEV) that was attenuated and capable of replicating only in vertebrate cells, an important safety feature for live vaccines against mosquito-borne viruses. The subgenomic promoter was inactivated with 13 synonymous mutations and expression of the EEEV structural proteins was placed under the control of an internal ribosomal entry site (IRES) derived from encephalomyocarditis virus (EMCV). We tested this vaccine candidate for virulence, viremia and efficacy in the murine model. A single subcutaneous immunization with 10(4) infectious units protected 100% of mice against intraperitoneal challenge with a highly virulent North American EEEV strain. None of the mice developed any signs of disease or viremia after immunization or following challenge. Our findings suggest that the IRES-based attenuation approach can be used to develop a safe and effective vaccine against EEE and other alphaviral diseases.

  14. Single-dose attenuated Vesiculovax vaccines protect primates against Ebola Makona virus.

    PubMed

    Mire, Chad E; Matassov, Demetrius; Geisbert, Joan B; Latham, Theresa E; Agans, Krystle N; Xu, Rong; Ota-Setlik, Ayuko; Egan, Michael A; Fenton, Karla A; Clarke, David K; Eldridge, John H; Geisbert, Thomas W

    2015-04-30

    The family Filoviridae contains three genera, Ebolavirus (EBOV), Marburg virus, and Cuevavirus. Some members of the EBOV genus, including Zaire ebolavirus (ZEBOV), can cause lethal haemorrhagic fever in humans. During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in over 10,000 deaths, and causing global concern of uncontrolled disease. To meet this challenge a rapid-acting vaccine is needed. Many vaccine approaches have shown promise in being able to protect nonhuman primates against ZEBOV. In response to the current ZEBOV outbreak several of these vaccines have been fast tracked for human use. However, it is not known whether any of these vaccines can provide protection against the new outbreak Makona strain of ZEBOV. One of these approaches is a first-generation recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing the ZEBOV glycoprotein (GP) (rVSV/ZEBOV). To address safety concerns associated with this vector, we developed two candidate, further-attenuated rVSV/ZEBOV vaccines. Both attenuated vaccines produced an approximately tenfold lower vaccine-associated viraemia compared to the first-generation vaccine and both provided complete, single-dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV.

  15. Single dose attenuated Vesiculovax vaccines protect primates against Ebola Makona virus

    PubMed Central

    Geisbert, Joan B.; Latham, Theresa E.; Agans, Krystle N.; Xu, Rong; Ota-Setlik, Ayuko; Egan, Michael A.; Fenton, Karla A.; Clarke, David K.; Eldridge, John H.; Geisbert, Thomas W.

    2015-01-01

    The family Filoviridae contains three genera, Ebolavirus (EBOV), Marburg virus, and Cuevavirus1. Some members of the EBOV genus, including Zaire ebolavirus (ZEBOV), can cause lethal hemorrhagic fever in humans. During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in nearly 10,000 deaths, and causing global concern of uncontrolled disease. To meet this challenge a rapid acting vaccine is needed. Many vaccine approaches have shown promise in being able to protect nonhuman primate (NHPs) against ZEBOV2. In response to the current ZEBOV outbreak several of these vaccines have been fast tracked for human use. However, it is not known whether any of these vaccines can provide protection against the new outbreak Makona strain of ZEBOV. One of these approaches is a first generation recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing the ZEBOV glycoprotein (GP) (rVSV/ZEBOV). To address safety concerns associated with this vector, we developed two candidate, further attenuated rVSV/ZEBOV vaccines. Both attenuated vaccines produced an approximately ten-fold lower vaccine-associated viremia compared to the first generation vaccine and both provided complete, single dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV. PMID:25853476

  16. [Development of new vaccines].

    PubMed

    González-Romo, Fernando; Picazo, Juan J

    2015-10-01

    Recent and important advances in the fields of immunology, genomics, functional genomics, immunogenetics, immunogenomics, bioinformatics, microbiology, genetic engineering, systems biology, synthetic biochemistry, proteomics, metabolomics and nanotechnology, among others, have led to new approaches in the development of vaccines. The better identification of ideal epitopes, the strengthening of the immune response due to new adjuvants, and the search of new routes of vaccine administration, are good examples of advances that are already a reality and that will favour the development of more vaccines, their use in indicated population groups, or its production at a lower cost. There are currently more than 130 vaccines are under development against the more wished (malaria or HIV), difficult to get (CMV or RSV), severe re-emerging (Dengue or Ebola), increasing importance (Chagas disease or Leishmania), and nosocomial emerging (Clostridium difficile or Staphylococcus aureus) infectious diseases.

  17. A Meta-Analysis of Experimental Studies of Attenuated Schistosoma mansoni Vaccines in the Mouse Model

    PubMed Central

    Fukushige, Mizuho; Mitchell, Kate M.; Bourke, Claire D.; Woolhouse, Mark E. J.; Mutapi, Francisca

    2015-01-01

    Schistosomiasis is a water-borne, parasitic disease of major public health importance. There has been considerable effort for several decades toward the development of a vaccine against the disease. Numerous mouse experimental studies using attenuated Schistosoma mansoni parasites for vaccination have been published since 1960s. However, to date, there has been no systematic review or meta-analysis of these data. The aim of this study is to identify measurable experimental conditions that affect the level of protection against re-infection with S. mansoni in mice vaccinated with radiation attenuated cercariae. Following a systematic review, a total of 755 observations were extracted from 105 articles (published 1963–2007) meeting the searching criteria. Random effects meta-regression models were used to identify the influential predictors. Three predictors were found to have statistically significant effects on the level of protection from vaccination: increasing numbers of immunizing parasites had a positive effect on fraction of protection whereas increasing radiation dose and time to challenge infection had negative effects. Models showed that the irradiated cercariae vaccine has the potential to achieve protection as high as 78% with a single dose vaccination. This declines slowly over time but remains high for at least 8 months after the last immunization. These findings provide insights into the optimal delivery of attenuated parasite vaccination and into the nature and development of protective vaccine induced immunity against schistosomiasis, which may inform the formulation of human vaccines and the predicted duration of protection and thus frequency of booster vaccines. PMID:25774157

  18. Clinical development of Ebola vaccines

    PubMed Central

    Sridhar, Saranya

    2015-01-01

    The ongoing outbreak of Ebola virus disease in West Africa highlighted the lack of a licensed drug or vaccine to combat the disease and has renewed the urgency to develop a pipeline of Ebola vaccines. A number of different vaccine platforms are being developed by assessing preclinical efficacy in animal models and expediting clinical development. Over 15 different vaccines are in preclinical development and 8 vaccines are now in different stages of clinical evaluation. These vaccines include DNA vaccines, virus-like particles and viral vectors such as live replicating vesicular stomatitis virus (rVSV), human and chimpanzee adenovirus, and vaccinia virus. Recently, in preliminary results reported from the first phase III trial of an Ebola vaccine, the rVSV-vectored vaccine showed promising efficacy. This review charts this rapidly advancing area of research focusing on vaccines in clinical development and discusses the future opportunities and challenges faced in the licensure and deployment of Ebola vaccines. PMID:26668751

  19. Kissing-loop interaction between 5' and 3' ends of tick-borne Langat virus genome 'bridges the gap' between mosquito- and tick-borne flaviviruses in mechanisms of viral RNA cyclization: applications for virus attenuation and vaccine development.

    PubMed

    Tsetsarkin, Konstantin A; Liu, Guangping; Shen, Kui; Pletnev, Alexander G

    2016-04-20

    Insertion of microRNA target sequences into the flavivirus genome results in selective tissue-specific attenuation and host-range restriction of live attenuated vaccine viruses. However, previous strategies for miRNA-targeting did not incorporate a mechanism to prevent target elimination under miRNA-mediated selective pressure, restricting their use in vaccine development. To overcome this limitation, we developed a new approach for miRNA-targeting of tick-borne flavivirus (Langat virus, LGTV) in the duplicated capsid gene region (DCGR). Genetic stability of viruses with DCGR was ensured by the presence of multiple cis-acting elements within the N-terminal capsid coding region, including the stem-loop structure (5'SL6) at the 3' end of the promoter. We found that the 5'SL6 functions as a structural scaffold for the conserved hexanucleotide motif at its tip and engages in a complementary interaction with the region present in the 3' NCR to enhance viral RNA replication. The resulting kissing-loop interaction, common in tick-borne flaviviruses, supports a single pair of cyclization elements (CYC) and functions as a homolog of the second pair of CYC that is present in the majority of mosquito-borne flaviviruses. Placing miRNA targets into the DCGR results in superior attenuation of LGTV in the CNS and does not interfere with development of protective immunity in immunized mice.

  20. Zika Vaccine Development: Flavivirus Foils

    DTIC Science & Technology

    2016-09-01

    Martins, Bavari, Zika Vaccine Development 1 Zika Vaccine Development: Flavivirus Foils Martins KAO, Bavari S. The current Zika virus...contrast, work had been underway for decades on the development of an Ebola virus vaccine , laying the groundwork for a rapid response in 2014. The...broader community’s extensive experience with Dengue virus vaccine development and with the pros and cons of different vaccine platforms has led to

  1. Protective efficacy of a live attenuated vaccine against Argentine hemorrhagic fever. AHF Study Group.

    PubMed

    Maiztegui, J I; McKee, K T; Barrera Oro, J G; Harrison, L H; Gibbs, P H; Feuillade, M R; Enria, D A; Briggiler, A M; Levis, S C; Ambrosio, A M; Halsey, N A; Peters, C J

    1998-02-01

    Argentine hemorrhagic fever (AHF), caused by the arenavirus Junin, is a major public health problem among agricultural workers in Argentina. A prospective, randomized, double-blind, placebo-controlled, efficacy trial of Candid 1, a live attenuated Junin virus vaccine, was conducted over two consecutive epidemic seasons among 6500 male agricultural workers in the AHF-endemic region. Twenty-three men developed laboratory-confirmed AHF during the study; 22 received placebo and 1 received vaccine (vaccine efficacy 95%; 95% confidence interval [CI], 82%-99%). Three additional subjects in each group developed laboratory-confirmed Junin virus infection associated with mild illnesses that did not fulfill the clinical case definition for AHF, yielding a protective efficacy for prevention of any illness associated with Junin virus infection of 84% (95% CI, 60%-94%). No serious adverse events were attributed to vaccination. Candid 1, the first vaccine for the prevention of illness caused by an arenavirus, is safe and highly efficacious.

  2. Optimization of efficacy of a live attenuated Flavobacterium psychrophilum immersion vaccine.

    PubMed

    Sudheesh, Ponnerassery S; Cain, Kenneth D

    2016-09-01

    This study was aimed at optimizing the efficacy of a recently developed live attenuated immersion vaccine (B.17-ILM) as a promising vaccine against bacterial coldwater disease (BCWD) caused by Flavobacterium psychrophilum in salmonids. Rainbow trout (RBT) fry were vaccinated by immersion, and different parameters affecting vaccination such as fish size, vaccine delivery time, dose, duration of protection, booster regimes and vaccine growth incubation time were optimized. Specific anti-F. psychrophilum immune response was determined by ELISA. Protective efficacy was determined by challenging with a virulent strain of F. psychrophilum (CSF-259-93) and calculating cumulative percent mortality (CPM) and relative percent survival (RPS). All vaccinated fish developed significantly higher levels of serum antibody titers by week 8 when compared to their respective controls. Immersion vaccination for 3, 6 and 30 min produced significant protection with comparable RPS values of 47%, 53% and 52%, respectively. This vaccine provided significant protection for fish as small as 0.5 g with an RPS of 55%; larger fish of 1 g and 2 g yielded slightly higher RPS values of 59% and 60%, respectively. Fish vaccinated with higher vaccine doses of ∼10(10) and 10(8) colony forming units mL(-1) (cfu ml(-1)) were strongly protected out to at least 24 weeks with RPS values up to 70%. Fish vaccinated with lower doses (∼10(6) and 10(5) cfu mL(-1)) had good protection out to 12 weeks, but RPS values dropped to 36% and 34%, respectively by 24 weeks. Vaccine efficacy was optimum when the primary vaccination was followed by a single booster (week 12 challenge RPS = 61%) rather than two boosters (week 12 challenge RPS = 48%). Vaccination without a booster resulted in a lower RPS (13%) indicating the necessity of a single booster vaccination to maximize efficacy. This study presents key findings that demonstrate the efficacy and commercial potential for this live attenuated BCWD

  3. Viral Inhibition of the IFN-Induced JAK/STAT Signalling Pathway: Development of Live Attenuated Vaccines by Mutation of Viral-Encoded IFN-Antagonists

    PubMed Central

    Fleming, Stephen B.

    2016-01-01

    The interferon (IFN) induced anti-viral response is amongst the earliest and most potent of the innate responses to fight viral infection. The induction of the Janus kinase/signal transducer and activation of transcription (JAK/STAT) signalling pathway by IFNs leads to the upregulation of hundreds of interferon stimulated genes (ISGs) for which, many have the ability to rapidly kill viruses within infected cells. During the long course of evolution, viruses have evolved an extraordinary range of strategies to counteract the host immune responses in particular by targeting the JAK/STAT signalling pathway. Understanding how the IFN system is inhibited has provided critical insights into viral virulence and pathogenesis. Moreover, identification of factors encoded by viruses that modulate the JAK/STAT pathway has opened up opportunities to create new anti-viral drugs and rationally attenuated new generation vaccines, particularly for RNA viruses, by reverse genetics. PMID:27367734

  4. A replication-deficient rabies virus vaccine expressing Ebola virus glycoprotein is highly attenuated for neurovirulence

    SciTech Connect

    Papaneri, Amy B.; Wirblich, Christoph; Cann, Jennifer A.; Cooper, Kurt; Jahrling, Peter B.; Schnell, Matthias J.; Blaney, Joseph E.

    2012-12-05

    We are developing inactivated and live-attenuated rabies virus (RABV) vaccines expressing Ebola virus (EBOV) glycoprotein for use in humans and endangered wildlife, respectively. Here, we further characterize the pathogenesis of the live-attenuated RABV/EBOV vaccine candidates in mice in an effort to define their growth properties and potential for safety. RABV vaccines expressing GP (RV-GP) or a replication-deficient derivative with a deletion of the RABV G gene (RV{Delta}G-GP) are both avirulent after intracerebral inoculation of adult mice. Furthermore, RV{Delta}G-GP is completely avirulent upon intracerebral inoculation of suckling mice unlike parental RABV vaccine or RV-GP. Analysis of RV{Delta}G-GP in the brain by quantitative PCR, determination of virus titer, and immunohistochemistry indicated greatly restricted virus replication. In summary, our findings indicate that RV-GP retains the attenuation phenotype of the live-attenuated RABV vaccine, and RV{Delta}G-GP would appear to be an even safer alternative for use in wildlife or consideration for human use.

  5. Immunity and protection by live attenuated HIV/SIV vaccines

    PubMed Central

    Wodarz, Dominik

    2008-01-01

    Live attenuated virus vaccines have shown the greatest potential to protect against simian immunodeficiency virus (SIV) infection, a model for human immunodeficiency virus (HIV). Immunity against the vaccine virus is thought to mediate protection. However, it is shown computationally that the opposite might be true. According to the model, the initial growth of the challenge strain, its peak load, and its potential to be pathogenic is higher if immunity against the vaccine virus is stronger. This is because the initial growth of the challenge strain is mainly determined by virus competition rather than immune suppression. The stronger the immunity against the vaccine strain, the weaker its competitive ability relative to the challenge strain, and the lower the level of protection. If the vaccine virus does protect the host against a challenge, it is because the competitive interactions between the viruses inhibit the initial growth of the challenge strain. According to these arguments, an inverse correlation between the level of attenuation and the level of protection is expected, and this has indeed been observed in experimental data. PMID:18586297

  6. Safety and immunogenicity of a live attenuated mumps vaccine

    PubMed Central

    Liang, Yan; Ma, Jingchen; Li, Changgui; Chen, Yuguo; Liu, Longding; Liao, Yun; Zhang, Ying; Jiang, Li; Wang, Xuan-Yi; Che, Yanchun; Deng, Wei; Li, Hong; Cui, Xiaoyu; Ma, Na; Ding, Dong; Xie, Zhongping; Cui, Pingfang; Ji, Qiuyan; Wang, Jingjing; Zhao, Yuliang; Wang, Junzhi; Li, Qihan

    2014-01-01

    Background: Mumps, a communicable, acute and previously well-controlled disease, has had recent and occasional resurgences in some areas. Methods: A randomized, double-blind, controlled and multistep phase I study of an F-genotype attenuated mumps vaccine produced in human diploid cells was conducted. A total of 300 subjects were enrolled and divided into 4 age groups: 16–60 years, 5–16 years, 2–5 years and 8–24 months. The groups were immunized with one injection per subject. Three different doses of the F-genotype attenuated mumps vaccine, A (3.5 ± 0.25 logCCID50), B (4.25 ± 0.25 logCCID50) and C (5.0 ± 0.25 logCCID50), as well as a placebo control and a positive control of a licensed A-genotype vaccine (S79 strain) were used. The safety and immunogenicity of this vaccine were compared with those of the controls. Results: The safety evaluation suggested that mild adverse reactions were observed in all groups. No serious adverse event (SAE) was reported throughout the trial. The immunogenicity test showed a similar seroconversion rate of the neutralizing and ELISA antibody in the 2- to 5-year-old and 8- to 24-month-old groups compared with the seroconversion rate in the positive control. The GMT of the neutralizing anti-F-genotype virus antibodies in the vaccine groups was slightly higher than that in the positive control group. Conclusions: The F-genotype attenuated mumps vaccine evaluated in this clinical trial was demonstrated to be safe and have effective immunogenicity vs. control. PMID:24614759

  7. Schistosoma japonicum: An ultraviolet-attenuated cercarial vaccine applicable in the field for water buffaloes

    SciTech Connect

    Shi, Y.E.; Jiang, C.F.; Han, J.J.; Li, Y.L.; Ruppel, A. )

    1990-07-01

    Water buffaloes were vaccinated three times with 10,000 Schistosoma japonicum cercariae irradiated with ultraviolet (uv) light at a dose of 400 microW x min/cm2. The irradiation was performed with cheap, simple, and portable equipment in a rural area of Hubei Province (People's Republic of China). A challenge infection of 1000 untreated cercariae was given to six vaccinated and six naive control buffaloes, while two vaccinated animals were not challenged. The experiment was terminated 6 weeks after the challenge. Control animals had lost body weight and harbored a mean of 110 worms and 37 eggs per gram of liver. The vaccinated animals gained weight after the challenge and developed 89% resistance to infection with S. japonicum. Since schistosomiasis japonica is nowadays transmitted in China predominantly by domestic livestock, a uv-attenuated cercarial vaccine for bovines may contribute to the control of this disease.

  8. Genetic characterisation of attenuated SAD rabies virus strains used for oral vaccination of wildlife.

    PubMed

    Geue, Lutz; Schares, Susann; Schnick, Christina; Kliemt, Jeannette; Beckert, Aline; Freuling, Conrad; Conraths, Franz J; Hoffmann, Bernd; Zanoni, Reto; Marston, Denise; McElhinney, Lorraine; Johnson, Nicholas; Fooks, Anthony R; Tordo, Noel; Müller, Thomas

    2008-06-19

    The elimination of rabies from the red fox (Vulpes vulpes) in Western Europe has been achieved by the oral rabies vaccination (ORV) of wildlife with a range of attenuated rabies virus strains. With the exception of the vaccinia rabies glycoprotein recombinant vaccine (VRG), all strains were originally derived from a common ancestor; the Street Alabama Dufferin (SAD) field strain. However, after more than 30 years of ORV it is still not possible to distinguish these vaccine strains and there is little information on the genetic basis for their attenuation. We therefore sequenced and compared the full-length genome of five commercially available SAD vaccine viruses (SAD B19, SAD P5/88, SAG2, SAD VA1 and SAD Bern) and four other SAD strains (the original SAD Bern, SAD VA1, ERA and SAD 1-3670 Wistar). Nucleotide sequencing allowed identifying each vaccine strain unambiguously. Phylogenetic analysis revealed that the majority of the currently used commercial attenuated rabies virus vaccines appear to be derived from SAD B19 rather than from SAD Bern. One commercially available vaccine virus did not contain the SAD strain mentioned in the product information of the producer. Two SAD vaccine strains appeared to consist of mixed genomic sequences. Furthermore, in-del events targeting A-rich sequences (in positive strand) within the 3' non-coding regions of M and G genes were observed in SAD-derivates developed in Europe. Our data also supports the idea of a possible recombination that had occurred during the derivation of the European branch of SAD viruses. If confirmed, this recombination event would be the first one reported among RABV vaccine strains.

  9. [Development of an AIDS vaccine: status report].

    PubMed

    Girard, M P

    2007-08-01

    After over 20 years of research and development (R&D) and more than 85 clinical trials using various candidate vaccines, there has been little progress in research for a vaccine against HIV/AIDS. This disappointing result raises serious doubts as to whether an effective HIV/AIDS vaccine will be available within a reasonable time frame. There are three main obstacles. The first is that the virus promptly enters into the genome of effector memory T-cells that then constitute an infection reservoir from which the virus cannot be dislodged. The second obstacle involves the genetic hyper-variability of the virus that can easily dodge host immune defenses by mutating. The third obstacle is that we are still unable to induce antibodies able to neutralize wild strains of the virus and block infection early. Current vaccines are designed to induce cellular immune responses - mostly of the CD8+ cytotoxic T cell (CTL) type - in the hope of limiting the clinical consequences of infection by reducing the rate of virus multiplication and decreasing virus load in recently infected persons. This strategy has led to development of numerous live attenuated vaccines using a wide variety of viral or bacterial vectors. These vaccines are currently being tested either singly or in various prime-boost combinations using several of these vaccines or DNA vaccines. The efficacy of these vaccination techniques in humans remains to be determined.

  10. [Impact of rotavirus vaccines in developing countries].

    PubMed

    Delacour, H

    2009-08-01

    Rotaviruses discovered in 1973 are the most common cause of severe diarrheal disease in infants and young children world-wide. Annually rotavirus infections are estimated to cause the deaths of more than 600,000 children under the age of 5 years with more than 90% of fatalities occurring in developing countries. In 2006 two live oral attenuated rotavirus vaccines were licensed: the monovalent human rotavirus vaccine (RotarixT) and the pentavalent bovine-human, reassortant vaccine (RotaTeqT). Both vaccines demonstrated excellent safety and protective effectiveness in large pre-licensing trials conducted in Europe, the United States and Latin America. Several countries in Latin and Central America have already decided to include rotavirus vaccines into their national immunization program. African and Asiatic countries have postponed their decisions pending the results of further studies.

  11. Dengue vaccine development: strategies and challenges.

    PubMed

    Ramakrishnan, Lakshmy; Pillai, Madhavan Radhakrishna; Nair, Radhakrishnan R

    2015-03-01

    Infection with dengue virus may result in dengue fever or a more severe outcome, such as dengue hemorrhagic syndrome/shock. Dengue virus infection poses a threat to endemic regions for four reasons: the presence of four serotypes, each with the ability to cause a similar disease outcome, including fatality; difficulties related to vector control; the lack of specific treatment; and the nonavailability of a suitable vaccine. Vaccine development is considered challenging due to the severity of the disease observed in individuals who have acquired dengue-specific immunity, either passively or actively. Therefore, the presence of vaccine-induced immunity against a particular serotype may prime an individual to severe disease on exposure to dengue virus. Vaccine development strategies include live attenuated vaccines, chimeric, DNA-based, subunit, and inactivated vaccines. Each of the candidates is in various stages of preclinical and clinical development. Issues pertaining to selection pressures, viral interaction, and safety still need to be evaluated in order to induce a complete protective immune response against all four serotypes. This review highlights the various strategies that have been employed in vaccine development, and identifies the obstacles to producing a safe and effective vaccine.

  12. Envelope exchange for the generation of live-attenuated arenavirus vaccines.

    PubMed

    Bergthaler, Andreas; Gerber, Nicolas U; Merkler, Doron; Horvath, Edit; de la Torre, Juan Carlos; Pinschewer, Daniel D

    2006-06-01

    Arenaviruses such as Lassa fever virus cause significant mortality in endemic areas and represent potential bioterrorist weapons. The occurrence of arenaviral hemorrhagic fevers is largely confined to Third World countries with a limited medical infrastructure, and therefore live-attenuated vaccines have long been sought as a method of choice for prevention. Yet their rational design and engineering have been thwarted by technical limitations. In addition, viral genes had not been identified that are needed to cause disease but can be deleted or substituted to generate live-attenuated vaccine strains. Lymphocytic choriomeningitis virus, the prototype arenavirus, induces cell-mediated immunity against Lassa fever virus, but its safety for humans is unclear and untested. Using this virus model, we have developed the necessary methodology to efficiently modify arenavirus genomes and have exploited these techniques to identify an arenaviral Achilles' heel suitable for targeting in vaccine design. Reverse genetic exchange of the viral glycoprotein for foreign glycoproteins created attenuated vaccine strains that remained viable although unable to cause disease in infected mice. This phenotype remained stable even after extensive propagation in immunodeficient hosts. Nevertheless, the engineered viruses induced T cell-mediated immunity protecting against overwhelming systemic infection and severe liver disease upon wild-type virus challenge. Protection was established within 3 to 7 d after immunization and lasted for approximately 300 d. The identification of an arenaviral Achilles' heel demonstrates that the reverse genetic engineering of live-attenuated arenavirus vaccines is feasible. Moreover, our findings offer lymphocytic choriomeningitis virus or other arenaviruses expressing foreign glycoproteins as promising live-attenuated arenavirus vaccine candidates.

  13. Development of Streptococcus pneumoniae Vaccines Using Live Vectors

    PubMed Central

    Wang, Shifeng; Curtiss, Roy

    2014-01-01

    Streptococcus pneumoniae still causes severe morbidity and mortality worldwide, especially in young children and the elderly. Much effort has been dedicated to developing protein-based universal vaccines to conquer the current shortcomings of capsular vaccines and capsular conjugate vaccines, such as serotype replacement, limited coverage and high costs. A recombinant live vector vaccine delivering protective antigens is a promising way to achieve this goal. In this review, we discuss the researches using live recombinant vaccines, mainly live attenuated Salmonella and lactic acid bacteria, to deliver pneumococcal antigens. We also discuss both the limitations and the future of these vaccines. PMID:25309747

  14. A candidate live inactivatable attenuated vaccine for AIDS.

    PubMed Central

    Chakrabarti, B K; Maitra, R K; Ma, X Z; Kestler, H W

    1996-01-01

    The recent discovery of long term AIDS nonprogressors who harbor nef-attenuated HIV suggests that a naturally occurring live vaccine for AIDS may already exist. Animal models have shown that a live vaccine for AIDS, attenuated in nef, is the best candidate vaccine. There are considerable risks, real and perceived, with the use of live HIV vaccines. We have introduced a conditional lethal genetic element into HIV-1 and simian immunodeficiency virus (SIV) molecular clones deleted in nef. The antiviral strategy we employed targets both virus replication and the survival of the infected cell. The suicide gene, herpes simplex virus thymidine kinase (tk), was expressed and maintained in HIV over long periods of time. Herpes simplex virus tk confers sensitivity to the antiviral activity of acyclic nucleosides such as ganciclovir (GCV). HIV-tk and SIV-tk replication were sensitive to GCV at subtoxic concentrations, and virus-infected cells were eliminated from tumor cell lines as well as primary cell cultures. We found the HIV-tk virus to be remarkably stable even after being cultured in media containing a low concentration of GCV and then challenged with the higher dose and that while GCV resistant escape mutants did arise, a significant fraction of the virus remained sensitive to GCV. Images Fig. 1 Fig. 5 PMID:8790413

  15. Antibody Response to Live Attenuated Vaccines in Adults in Japan

    PubMed Central

    Uchiyama-Nakamura, Fukumi; Sugata-Tsubaki, Aiko; Yamada, Yutaka; Uno, Kenji; Kasahara, Kei; Maeda, Koichi; Konishi, Mitsuru; Mikasa, Keiichi

    2016-01-01

    Abstract The purpose of this study was to examine the efficacy rendered with a single dose of live attenuated measles, rubella, mumps, and varicella containing vaccine. We inoculated healthcare workers (HCWs) with a single dose of vaccine to a disease lacking in antibody titer for those not meeting the criteria of our hospital (measles: <16.0 (IgG enzyme immunoassay (EIA)), rubella: ≤1:32 (hemagglutination-inhibition), mumps: <4.0 (IgG EIA), and varicella: <4.0 (IgG EIA)). At 28–60 days after vaccination, the antibody titer was tested again. We included 48 HCWs. A total of 32, 15, 31, and 10 individuals were inoculated with a single dose of measles-containing, rubella-containing, mumps, or varicella vaccine, respectively, and showed significant antibody elevation (9.2 ± 12.3 to 27.6 ± 215.6, p<0.001; 8 ± 1.2 to 32 ± 65.5, p<0.001; 3.0 ± 1.0 to 13.1 ± 8.6, p<0.05; and 2.6 ± 1.3 to 11.8 ± 8.1, p<0.001, respectively). Major side effects were not observed. In a limited population, a single dose of live attenuated vaccine showed elevation of antibody titer without any severe adverse reactions. However, whether the post-vaccination response rate criteria of our university was fulfilled could not be determined owing to limited sample size. PMID:28352840

  16. CANINE DISTEMPER VIRUS ANTIBODY TITERS IN DOMESTIC CATS AFTER DELIVERY OF A LIVE ATTENUATED VIRUS VACCINE.

    PubMed

    Ramsay, Edward; Sadler, Ryan; Rush, Robert; Seimon, Tracie; Tomaszewicz, Ania; Fleetwood, Ellen A; McAloose, Denise; Wilkes, Rebecca P

    2016-06-01

    Three methods for delivering a live attenuated canine distemper virus (CDV) vaccine to domestic cats ( Felis catus ) were investigated, as models for developing vaccination protocols for tigers (Panthera tigris). Twenty domestic cats were randomly divided into four treatment groups: saline injection (negative controls); and oral, intranasal, and subcutaneous vaccinates. Cats were injected with saline or a CDV vaccine (Nobivac DP, Merck) at wk 0 and 4. Blood and nasal swabs were collected at wk 0 (prior to the initial vaccination) and weekly thereafter for 9 wk. Urine samples were collected on wk 1 to 9 after initial vaccination. Forty-nine weeks following the initial vaccination series, three cats from the subcutaneous group and three cats from the intranasal group were revaccinated. Blood was collected immediately prior, and 7 and 21 days subsequent to revaccination. Nasal swabs and urine samples were collected from each cat prior to wk 49 revaccination and daily for 7 days thereafter. Nasal swabs and urine were analyzed by quantitative PCR for vaccine virus presence. Sera were tested for CDV antibodies by virus neutralization. All cats were sero-negative for CDV antibodies at the beginning of the study, and saline-injected cats remained sero-negative throughout the study. A dramatic anamnestic response was seen following wk 4 subcutaneous vaccinations, with titers peaking at wk 6 (geometric mean = 2,435.5). Following wk 49 revaccination, subcutaneous vaccinates again mounted impressive titers (wk 52 geometric mean = 2,048). Revaccination of the intranasal group cats at wk 49 produced a small increase in titers (wk 52 geometric mean = 203). CDV viral RNA was detected in six nasal swabs but no urine samples, demonstrating low viral shedding postvaccination. The strong antibody response to subcutaneous vaccination and the lack of adverse effects suggest this vaccine is safe and potentially protective against CDV infection in domestic cats.

  17. A pilot study on an attenuated Chinese EIAV vaccine inducing broadly neutralizing antibodies.

    PubMed

    Meng, Qinglai; Lin, Yuezhi; Ma, Jian; Ma, Yan; Zhao, Liping; Li, Shenwei; Liang, Hua; Zhou, Jianhua; Shen, Rongxian; Zhang, Xiaoyan; Shao, Yiming

    2011-08-01

    The attenuated Chinese equine infectious anemia virus (EIAV) vaccine has successfully protected millions of equine animals from EIA disease in China. In this pilot study, to determine whether this attenuated vaccine can induce broadly neutralizing antibodies, we immunized four horses with the attenuated Chinese vaccine strain EIAVFDDV and then observed the evolution of neutralizing antibodies against different EIAV strains. During the vaccination phase, all vaccinees rapidly developed high levels of neutralizing antibodies against the homologous vaccine strain (pLGFD3V), and 3 out of 4 horses showed a gradual increase in serum neutralizing activity against two relatively heterologous virulent variants of the challenge strain (pLGFD3Mu12V and DLV34). After challenge, the three horses that had developed high levels of neutralizing antibodies against pLGFD3Mu12V and DLV34 did not show signs of infection, which was demonstrated by immune suppression, while the one horse producing serum that could only neutralize pLGFD3V developed a febrile episode during the 8-month observation period. To assess whether the broadly neutralizing activity is associated with immune protection, sera drawn on the day of challenge from these four vaccinees and an additional four EIAVFDDV-vaccinated horses were analyzed for neutralizing antibodies against pLGFD3V, pLGFD3Mu12V and DLV34. Although there was no significant correlation between protection from infection and serum neutralizing activity against any of these three viral strains, protection from infection was observed to correlate better with serum neutralizing activity against the two heterologous virulent strains than against the homologous vaccine strain. These data indicate that EIAVFDDV induced broadly neutralizing antibodies, which might confer enhanced protection of vaccinees from infection by the challenge virus.

  18. Protection Against Dengue Virus by Non-Replicating and Live Attenuated Vaccines Used Together in a Prime Boost Vaccination Strategy

    DTIC Science & Technology

    2010-01-01

    Protection against dengue virus by non-replicating and live attenuated vaccines used together in a prime boost vaccination strategy Monika Simmons a...Dengue DNA Punfied inacdvared virus Uvc artenuatcd virus Jlnmc boost A new vaccination strategy for dengue virus (DENV) was eval uated in rhesus...region (TDNA) then boosting 2 months l,ltcr with a tetravalent live aucnuated virus (TLAV) vaccine . Both vaccine combinations elicited virus

  19. Stable Salmonella live vaccine strains with two or more attenuating mutations and any desired level of attenuation.

    PubMed

    Linde, K; Beer, J; Bondarenko, V

    1990-06-01

    Mutants optimally attenuated for highly susceptible hosts and protecting after a single oral vaccination are often overattenuated for host species being less susceptible. Therefore, to select vaccine strains optimally attenuated for the particular host species it is essential that a range of mutants with graded levels of attenuation be provided so as to permit lesser susceptibility to be compensated for by a correspondingly lower level of attenuation. This, while guaranteeing the stability through two-marker or multi-marker attenuation, can be suitably accomplished by slightly to moderately virulence-reducing mutations. Aspartic acid auxotrophy and, in particular, 'metabolic drift' mutations, possibly by additionally incorporating antiepidemic markers, are adopted for the mouse model to demonstrate stepwise production of S. typhimurium and S. typhi vaccine candidate strains with graded attenuation or any level of attenuation desirable. It is emphasized that this basic approach is relevant to practice.

  20. Developments in rabies vaccines.

    PubMed

    Hicks, D J; Fooks, A R; Johnson, N

    2012-09-01

    The development of vaccines that prevent rabies has a long and distinguished history, with the earliest preceding modern understanding of viruses and the mechanisms of immune protection against disease. The correct application of inactivated tissue culture-derived vaccines is highly effective at preventing the development of rabies, and very few failures are recorded. Furthermore, oral and parenteral vaccination is possible for wildlife, companion animals and livestock, again using inactivated tissue culture-derived virus. However, rabies remains endemic in many regions of the world and causes thousands of human deaths annually. There also remain no means of prophylaxis for rabies once the virus enters the central nervous system (CNS). One reason for this is the poor immune response within the CNS to infection with rabies virus (RABV). New approaches to vaccination using modified rabies viruses that express components of the innate immune system are being applied to this problem. Preliminary reports suggest that direct inoculation of such viruses could trigger an effective anti-viral response and prevent a fatal outcome from RABV infection.

  1. A high-temperature passaging attenuated Pseudorabies vaccine protects piglets completely against emerging PRV variant.

    PubMed

    Liang, Chao; Tong, Wu; Zheng, Hao; Liu, Fei; Wu, Jiqiang; Li, Guoxin; Zhou, En-Min; Tong, Guangzhi

    2017-02-13

    Emerging variant of pseudorabies virus (PRV) have evaded the antiviral immunity of commercially available PRV vaccine and have led to PRV outbreaks in Chinese pig farms. Here, we attenuated a PRV variant strain by serial passages in vitro and evaluate the protective efficacy of the attenuated strain as a vaccine candidate. The virulent PRV variant strain JS-2012 was continuously passaged in Vero cells at 40°C and attenuated rapidly. After 90 passages in Vero cells, the passaged virus lost its ability to cause death in 2-week-old piglets. The 120th passage virus was avirulent in the sucking piglets. An attenuated strain, JS-2012-F120 derived from the 120th passage virus by three rounds of plaque cloning grew better than its parent strain JS-2012 in Vero cells and showed notably different cytopathic effects and plaque morphology from JS-2012. PCR combined with sequence analysis showed that JS-2012-F120 contained a 2307-bp deletion covering nucleotide 487 of gE gene to 531 of US2 gene. After inoculation with JS-2012-F120, young piglets were completely protected from challenge with the classical and emerging virulent PRVs. Moreover, the piglets did not develop specific gE antibodies. Thus, JS-2012-F120 appears to be a promising marker vaccine to control PRV variant circulating in Chinese pig farms, and the high-temperature passaging in vitro was an efficient method to attenuated alphaherpesvirus.

  2. Tuberculosis vaccine development: recent progress.

    PubMed

    Orme, I M; McMurray, D N; Belisle, J T

    2001-03-01

    Recent years have seen a renewed effort to develop new vaccines against tuberculosis. As a result, several promising avenues of research have developed, including the production of recombinant vaccines, auxotrophic vaccines, DNA vaccines and subunit vaccines. In this article we briefly review this work, as well as consider the pros and cons of the animal models needed to test these new vaccines. Screening to date has been carried out in mouse and guinea pig models, which have been used to obtain basic information such as the effect of the vaccine on bacterial load, and whether the vaccine can prevent or reduce lung pathology. The results to date lead us to be optimistic that new candidate vaccines could soon be considered for evaluation in clinical trials.

  3. Effect of attenuated Erysipelothrix rhusiopathiae vaccine in pigs infected with porcine reproductive respiratory syndrome virus.

    PubMed

    Sakano, T; Shibata, I; Namimatsu, T; Mori, M; Ono, M; Uruno, K; Osumi, T

    1997-11-01

    Twenty 2nd specific pathogen-free pigs were divided into 4 groups: Group A were infected with porcine reproductive and respiratory syndrome (PRRS) virus at 6 weeks of age and treated with available swine erysipelas and swine fever combined vaccine (vaccinated) at 7 weeks of age; Group B were vaccinated at 7 weeks of age and infected with PRRS virus at 8 weeks of age; Group C were vaccinated at 7 weeks of age: Group D were neither vaccinated nor infected with PRRS virus. All pigs were challenged to Erysipelothrix rhusiopathiae C42 strain at 10 weeks of age. No clinical signs appeared after vaccination of group A and B pigs, thus confirming that the safety of the vaccine was not influenced by infection with PRRS virus. None of the pigs in Groups A and C developed erysipelas after challenge exposure to E. rhusiopathiae. In contrast, fever and/or urticaria appeared transiently in all pigs of Group B after challenge exposure. At the time of challenge exposure to E. rhusiopathiae, the PRRS virus titer was high in sera of Group B, but was low in those from Group A. However, vaccination of pigs with attenuated E. rhusiopathiae was effective in dual infection with PRRS virus and E. rhusiopathiae, because the clinical signs were milder and the E. rhusiopathiae strain was less recovered from these pigs compared to pigs of group D.

  4. Genetically modified, live attenuated dengue virus type 3 vaccine candidates.

    PubMed

    Blaney, Joseph E; Hanson, Christopher T; Firestone, Cai-Yen; Hanley, Kathryn A; Murphy, Brian R; Whitehead, Stephen S

    2004-12-01

    Three novel recombinant dengue type 3 (DEN3) virus vaccine candidates have been generated from a DEN3 virus isolated from a mild outbreak of dengue fever in the Sleman area of central Java in Indonesia in 1978. Antigenic chimeric viruses were prepared by replacing the membrane precursor and envelope (ME) proteins of recombinant DEN4 (rDEN4) virus with those from DEN3 Sleman/78 in the presence (rDEN3/4Delta30(ME)) and the absence (rDEN3/4(ME)) of the Delta30 mutation, a previously described 30-nucleotide deletion in the 3' untranslated region. In addition, a full-length infectious cDNA clone was generated from the DEN3 isolate and used to produce rDEN3 virus and the vaccine candidate rDEN3Delta30. The chimeric viruses rDEN3/4(ME) and rDEN3/4Delta30(ME) appear to be acceptable vaccine candidates since they were restricted in replication in severe combined immune deficiency mice transplanted with human hepatoma cells, in rhesus monkeys, and in Aedes and Toxorynchites mosquitoes, and each was protective in rhesus monkeys against DEN3 virus challenge. The rDEN3/4(ME) and rDEN3/4Delta30(ME) viruses were comparable in all parameters evaluated, indicating that antigenic chimerization resulted in the observed high level of attenuation. Surprisingly, rDEN3Delta30 was not attenuated in any model tested when compared with wild-type rDEN3 and therefore, is not a vaccine candidate at present. Thus, the rDEN3/4(ME) and rDEN3/4Delta30(ME) antigenic chimeric viruses can be considered for evaluation in humans and for inclusion in a tetravalent dengue vaccine.

  5. Mucosal Vaccine Development Based on Liposome Technology

    PubMed Central

    Norling, Karin; Bally, Marta; Höök, Fredrik

    2016-01-01

    Immune protection against infectious diseases is most effective if located at the portal of entry of the pathogen. Hence, there is an increasing demand for vaccine formulations that can induce strong protective immunity following oral, respiratory, or genital tract administration. At present, only few mucosal vaccines are found on the market, but recent technological advancements and a better understanding of the principles that govern priming of mucosal immune responses have contributed to a more optimistic view on the future of mucosal vaccines. Compared to live attenuated vaccines, subcomponent vaccines, most often protein-based, are considered safer, more stable, and less complicated to manufacture, but they require the addition of nontoxic and clinically safe adjuvants to be effective. In addition, another limiting factor is the large antigen dose that usually is required for mucosal vaccines. Therefore, the combination of mucosal adjuvants with the recent progress in nanoparticle technology provides an attractive solution to these problems. In particular, the liposome technology is ideal for combining protein antigen and adjuvant into an effective mucosal vaccine. Here, we describe and discuss recent progress in nanoparticle formulations using various types of liposomes that convey strong promise for the successful development of the next generation of mucosal vaccines. PMID:28127567

  6. Clinical Impact of Vaccine Development.

    PubMed

    Nambiar, Puja H; Daza, Alejandro Delgado; Livornese, Lawrence L

    2016-01-01

    The discovery and development of immunization has been a singular improvement in the health of mankind. This chapter reviews currently available vaccines, their historical development, and impact on public health. Specific mention is made in regard to the challenges and pursuit of a vaccine for the human immunodeficiency virus as well as the unfounded link between autism and measles vaccination.

  7. [Research and development strategies, examples among new vaccines].

    PubMed

    Denis, F; Ploy, M-C

    2009-05-01

    Classical methods are still providing new vaccines, but molecular biology and genetic engineering have enabled new approaches to development. Changes in vaccinology have involved the isolation, presentation and administration of vaccinal antigens or attenuated vaccinal strains. New methods of vaccine delivery other than injection will be used (e.g. mucosal administration) and new vectors or adjuvants will be added to vaccines in order to stimulate specific responses. New vaccines can also be obtained by using viral-like particles (VLP of papillomavirus), conjugate polysaccharides (N. meningitidis, S. pneumoniae) or the reassortment of segmented genomes (rotavirus, influenza). Here, we analyze the different steps of a vaccine's life using concrete cases of two new vaccines against papillomavirus and rotavirus. Vaccination has a promising future.

  8. Review: New Vaccine Against Tuberculosis: Current Developments and Future Challenges

    NASA Astrophysics Data System (ADS)

    Liu, Jun

    2009-04-01

    Tuberculosis (TB) continues to be a global health threat. BCG was developed as an attenuated live vaccine for tuberculosis control nearly a century ago. Despite being the most widely used vaccine in human history, BCG is not an ideal vaccine and has two major limitations: its poor efficacy against adult pulmonary TB and its disconcerting safety in immunocompromised individuals. A safer and more effective TB vaccine is urgently needed. This review article discusses current strategies to develop the next generation of TB vaccines to replace BCG. While some progresses have been made in the past decade, significant challenges lie ahead.

  9. Live Attenuated Human Salmonella Vaccine Candidates: tracking the pathogen in natural infection and stimulation of host immunity

    PubMed Central

    Galen, James E.; Buskirk, Amanda D.; Tennant, Sharon M.; Pasetti, Marcela F.

    2016-01-01

    Salmonellosis, caused by members of the genus Salmonella, is responsible for considerable global morbidity and mortality, in both animals and humans. In this review, we will discuss the pathogenesis of S. Typhi and S. Typhimurium, focusing on human Salmonella infections. We will trace the path of Salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of host immunity. Careful consideration of the natural progression of disease provides an important context in which attenuated live oral vaccines can be rationally designed and developed. With this in mind, we will describe a series of attenuated live oral vaccines that have been successfully tested in clinical trials and demonstrated to be both safe and highly immunogenic. The attenuation strategies summarized in this review offer important insights into further development of attenuated vaccines against other Salmonella for which live oral candidates are currently unavailable. PMID:27809955

  10. Live Attenuated Human Salmonella Vaccine Candidates: Tracking the Pathogen in Natural Infection and Stimulation of Host Immunity.

    PubMed

    Galen, James E; Buskirk, Amanda D; Tennant, Sharon M; Pasetti, Marcela F

    2016-11-01

    Salmonellosis, caused by members of the genus Salmonella, is responsible for considerable global morbidity and mortality in both animals and humans. In this review, we will discuss the pathogenesis of Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium, focusing on human Salmonella infections. We will trace the path of Salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of host immunity. Careful consideration of the natural progression of disease provides an important context in which attenuated live oral vaccines can be rationally designed and developed. With this in mind, we will describe a series of attenuated live oral vaccines that have been successfully tested in clinical trials and demonstrated to be both safe and highly immunogenic. The attenuation strategies summarized in this review offer important insights into further development of attenuated vaccines against other Salmonella for which live oral candidates are currently unavailable.

  11. Seasonal Effectiveness of Live Attenuated and Inactivated Influenza Vaccine

    PubMed Central

    Flannery, Brendan; Thompson, Mark G.; Gaglani, Manjusha; Jackson, Michael L.; Monto, Arnold S.; Nowalk, Mary Patricia; Talbot, H. Keipp; Treanor, John J.; Belongia, Edward A.; Murthy, Kempapura; Jackson, Lisa A.; Petrie, Joshua G.; Zimmerman, Richard K.; Griffin, Marie R.; McLean, Huong Q.; Fry, Alicia M.

    2016-01-01

    BACKGROUND: Few observational studies have evaluated the relative effectiveness of live attenuated (LAIV) and inactivated (IIV) influenza vaccines against medically attended laboratory-confirmed influenza. METHODS: We analyzed US Influenza Vaccine Effectiveness Network data from participants aged 2 to 17 years during 4 seasons (2010–2011 through 2013–2014) to compare relative effectiveness of LAIV and IIV against influenza-associated illness. Vaccine receipt was confirmed via provider/electronic medical records or immunization registry. We calculated the ratio (odds) of influenza-positive to influenza-negative participants among those age-appropriately vaccinated with either LAIV or IIV for the corresponding season. We examined relative effectiveness of LAIV and IIV by using adjusted odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regression. RESULTS: Of 6819 participants aged 2 to 17 years, 2703 were age-appropriately vaccinated with LAIV (n = 637) or IIV (n = 2066). Odds of influenza were similar for LAIV and IIV recipients during 3 seasons (2010–2011 through 2012–2013). In 2013–2014, odds of influenza were significantly higher among LAIV recipients compared with IIV recipients 2 to 8 years old (OR 5.36; 95% CI, 2.37 to 12.13). Participants vaccinated with LAIV or IIV had similar odds of illness associated with influenza A/H3N2 or B. LAIV recipients had greater odds of illness due to influenza A/H1N1pdm09 in 2010–2011 and 2013–2014. CONCLUSIONS: We observed lower effectiveness of LAIV compared with IIV against influenza A/H1N1pdm09 but not A(H3N2) or B among children and adolescents, suggesting poor performance related to the LAIV A/H1N1pdm09 viral construct. PMID:26738884

  12. DIVERGENCE, NOT DIVERSITY OF AN ATTENUATED EQUINE LENTIVIRUS VACCINE STRAIN CORRELATES WITH PROTECTION FROM DISEASE

    PubMed Central

    Craigo, Jodi K.; Barnes, Shannon; Cook, Sheila J.; Issel, Charles J.; Montelaro, Ronald C.

    2010-01-01

    We recently reported an attenuated EIAV vaccine study that directly examined the effect of lentiviral envelope sequence variation on vaccine efficacy. The study [1] demonstrated for the first time the failure of an ancestral vaccine to protect and revealed a significant, inverse, linear relationship between envelope divergence and protection from disease. In the current study we examine in detail the evolution of the attenuated vaccine strain utilized in this previous study. We demonstrate here that the attenuated strain progressively evolved during the six-month pre-challenge period and that the observed protection from disease was significantly associated with divergence from the original vaccine strain. PMID:20955830

  13. Live attenuated B. pertussis as a single-dose nasal vaccine against whooping cough.

    PubMed

    Mielcarek, Nathalie; Debrie, Anne-Sophie; Raze, Dominique; Bertout, Julie; Rouanet, Carine; Younes, Amena Ben; Creusy, Colette; Engle, Jacquelyn; Goldman, William E; Locht, Camille

    2006-07-01

    Pertussis is still among the principal causes of death worldwide, and its incidence is increasing even in countries with high vaccine coverage. Although all age groups are susceptible, it is most severe in infants too young to be protected by currently available vaccines. To induce strong protective immunity in neonates, we have developed BPZE1, a live attenuated Bordetella pertussis strain to be given as a single-dose nasal vaccine in early life. BPZE1 was developed by the genetic inactivation or removal of three major toxins. In mice, BPZE1 was highly attenuated, yet able to colonize the respiratory tract and to induce strong protective immunity after a single nasal administration. Protection against B. pertussis was comparable to that induced by two injections of acellular vaccine (aPV) in adult mice, but was significantly better than two administrations of aPV in infant mice. Moreover, BPZE1 protected against Bordetella parapertussis infection, whereas aPV did not. BPZE1 is thus an attractive vaccine candidate to protect against whooping cough by nasal, needle-free administration early in life, possibly at birth.

  14. Live Attenuated B. pertussis as a Single-Dose Nasal Vaccine against Whooping Cough

    PubMed Central

    Mielcarek, Nathalie; Debrie, Anne-Sophie; Raze, Dominique; Bertout, Julie; Rouanet, Carine; Younes, Amena Ben; Creusy, Colette; Engle, Jacquelyn; Goldman, William E; Locht, Camille

    2006-01-01

    Pertussis is still among the principal causes of death worldwide, and its incidence is increasing even in countries with high vaccine coverage. Although all age groups are susceptible, it is most severe in infants too young to be protected by currently available vaccines. To induce strong protective immunity in neonates, we have developed BPZE1, a live attenuated Bordetella pertussis strain to be given as a single-dose nasal vaccine in early life. BPZE1 was developed by the genetic inactivation or removal of three major toxins. In mice, BPZE1 was highly attenuated, yet able to colonize the respiratory tract and to induce strong protective immunity after a single nasal administration. Protection against B. pertussis was comparable to that induced by two injections of acellular vaccine (aPV) in adult mice, but was significantly better than two administrations of aPV in infant mice. Moreover, BPZE1 protected against Bordetella parapertussis infection, whereas aPV did not. BPZE1 is thus an attractive vaccine candidate to protect against whooping cough by nasal, needle-free administration early in life, possibly at birth. PMID:16839199

  15. Evaluation of attenuated Salmonella choleraesuis-mediated inhibin recombinant DNA vaccine in rats.

    PubMed

    Hui, F M; Meng, C L; Guo, N N; Yang, L G; Shi, F X; Mao, D G

    2014-08-07

    DNA vaccination has been studied intensively as a potential vaccine technology. We evaluated the effect of an attenuated Salmonella choleraesuis-mediated inhibin DNA vaccine in rats. First, 15 rats were treated with different doses of an inhibin vaccine to evaluate vaccine safety. Next, 30 rats were divided into 3 groups and injected intramuscularly with the inhibin vaccine two (T1) or three times (T2) or with control bacteria (Con) at 4-week intervals. The inhibin antibody levels increased [positive/negative well (P/N) value: T1 vs Con = 2.39 ± 0.01 vs 1.08 ± 0.1; T2 vs Con = 2.36 ± 0.1 vs 1.08 ± 0.1, P < 0.05] at week 2 and were maintained at a high level in T1 and T2 until week 8, although a small decrease in T2 was observed at week 10. Rats in the T1 group showed more corpora lutea compared with the Con group (10.50 ± 0.87 vs 7.4 ± 0.51, P < 0.05). Estradiol (0.439 ± 0.052 vs 0.719 ± 0.063 ng/mL, P < 0.05) and progesterone (1.315 ± 0.2 vs 0.737 ± 0.11 ng/mL, P < 0.05) levels differed significantly at metestrus after week 10 between rats in the T1 and Con groups. However, there were no significant differences in body, ovary, uterus weights, or pathological signs in the ovaries after immunization, indicating that this vaccine is safe. In conclusion, the attenuated S. choleraesuis-mediated inhibin vaccine may be an alternative to naked inhibin plasmids for stimulating ovarian follicular development to increase the ovulation rate in rats.

  16. Superior protection elicited by live-attenuated vaccines in the murine model of paratuberculosis.

    PubMed

    Ghosh, Pallab; Shippy, Daniel C; Talaat, Adel M

    2015-12-16

    Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) causes Johne's disease, a chronic enteric infection in ruminants with severe economic impact on the dairy industry in the USA and worldwide. Currently, available vaccines have limited protective efficacy against disease progression and does not prevent spread of the infection among animals. Because of their ability to elicit wide-spectrum immune responses, we adopted a live-attenuated vaccine approach based on a sigH knock-out strain of M. paratuberculosis (ΔsigH). Earlier analysis of the ΔsigH mutant in mice indicated their inadequate ability to colonize host tissues, unlike the isogenic wild-type strain, validating the role of this sigma factor in M. paratuberculosis virulence. In the present study, we evaluated the performance of the ΔsigH mutant compared to inactivated vaccine constructs in a vaccine/challenge model of murine paratuberculosis. The presented analysis indicated that ΔsigH mutant with or without QuilA adjuvant is capable of eliciting strong immune responses (such as interferon gamma-γ, IFN-γ) suggesting their immunogenicity and ability to potentially initiate effective vaccine-induced immunity. Following a challenge with virulent strains of M. paratuberculosis, ΔsigH conferred protective immunity as indicated by the reduced bacterial burden accompanied with reduced lesions in main body organs (liver, spleen and intestine) usually infected with M. paratuberculosis. More importantly, our data indicated better ability of the ΔsigH vaccine to confer protection compared to the inactivated vaccine constructs even with the presence of oil-adjuvant. Overall, our approach provides a rational basis for using live-attenuated mutant strains to develop improved vaccines that elicit robust immunity against this chronic infection.

  17. Biomarkers of safety and immune protection for genetically modified live attenuated leishmania vaccines against visceral leishmaniasis - discovery and implications.

    PubMed

    Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L

    2014-01-01

    Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen(-/-) in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

  18. The Major Determinant of Attenuation in Mice of the Candid1 Vaccine for Argentine Hemorrhagic Fever Is Located in the G2 Glycoprotein Transmembrane Domain▿

    PubMed Central

    Albariño, César G.; Bird, Brian H.; Chakrabarti, Ayan K.; Dodd, Kimberly A.; Flint, Mike; Bergeron, Éric; White, David M.; Nichol, Stuart T.

    2011-01-01

    Candid1, a live-attenuated Junin virus vaccine strain, was developed during the early 1980s to control Argentine hemorrhagic fever, a severe and frequently fatal human disease. Six amino acid substitutions were found to be unique to this vaccine strain, and their role in virulence attenuation in mice was analyzed using a series of recombinant viruses. Our results indicate that Candid1 is attenuated in mice through a single amino acid substitution in the transmembrane domain of the G2 glycoprotein. This work provides insight into the molecular mechanisms of attenuation of the only arenavirus vaccine currently available. PMID:21795336

  19. Generation of a Live Attenuated Influenza Vaccine that Elicits Broad Protection in Mice and Ferrets.

    PubMed

    Wang, Lulan; Liu, Su-Yang; Chen, Hsiang-Wen; Xu, Juan; Chapon, Maxime; Zhang, Tao; Zhou, Fan; Wang, Yao E; Quanquin, Natalie; Wang, Guiqin; Tian, Xiaoli; He, Zhanlong; Liu, Longding; Yu, Wenhai; Sanchez, David Jesse; Liang, Yuying; Jiang, Taijiao; Modlin, Robert; Bloom, Barry R; Li, Qihan; Deng, Jane C; Zhou, Paul; Qin, F Xiao-Feng; Cheng, Genhong

    2017-03-08

    New influenza vaccines that provide effective and broad protection are desperately needed. Live attenuated viruses are attractive vaccine candidates because they can elicit both humoral and cellular immune responses. However, recent formulations of live attenuated influenza vaccines (LAIVs) have not been protective. We combined high-coverage transposon mutagenesis of influenza virus with a rapid high-throughput screening for attenuation to generate W7-791, a live attenuated mutant virus strain. W7-791 produced only a transient asymptomatic infection in adult and neonatal mice even at doses 100-fold higher than the LD50 of the parent strain. A single administration of W7-791 conferred full protection to mice against lethal challenge with H1N1, H3N2, and H5N1 strains, and improved viral clearance in ferrets. Adoptive transfer of T cells from W7-791-immunized mice conferred heterologous protection, indicating a role for T cell-mediated immunity. These studies present an LAIV development strategy to rapidly generate and screen entire libraries of viral clones.

  20. A live-attenuated Zika virus vaccine candidate induces sterilizing immunity in mouse models.

    PubMed

    Shan, Chao; Muruato, Antonio E; Nunes, Bruno T D; Luo, Huanle; Xie, Xuping; Medeiros, Daniele B A; Wakamiya, Maki; Tesh, Robert B; Barrett, Alan D; Wang, Tian; Weaver, Scott C; Vasconcelos, Pedro F C; Rossi, Shannan L; Shi, Pei-Yong

    2017-04-10

    Zika virus (ZIKV) infection of pregnant women can cause a wide range of congenital abnormalities, including microcephaly, in the infant, a condition now collectively known as congenital ZIKV syndrome. A vaccine to prevent or significantly attenuate viremia in pregnant women who are residents of or travelers to epidemic or endemic regions is needed to avert congenital ZIKV syndrome, and might also help to suppress epidemic transmission. Here we report on a live-attenuated vaccine candidate that contains a 10-nucleotide deletion in the 3' untranslated region of the ZIKV genome (10-del ZIKV). The 10-del ZIKV is highly attenuated, immunogenic, and protective in type 1 interferon receptor-deficient A129 mice. Crucially, a single dose of 10-del ZIKV induced sterilizing immunity with a saturated neutralizing antibody titer, which no longer increased after challenge with an epidemic ZIKV, and completely prevented viremia. The immunized mice also developed a robust T cell response. Intracranial inoculation of 1-d-old immunocompetent CD-1 mice with 1 × 10(4) infectious focus units (IFU) of 10-del ZIKV caused no mortality, whereas infections with 10 IFU of wild-type ZIKV were lethal. Mechanistically, the attenuated virulence of 10-del ZIKV may be due to decreased viral RNA synthesis and increased sensitivity to type-1-interferon inhibition. The attenuated 10-del ZIKV was incapable of infecting mosquitoes after oral feeding of spiked-blood meals, representing an additional safety feature. Collectively, the safety and efficacy results suggest that further development of this promising, live-attenuated ZIKV vaccine candidate is warranted.

  1. Recombinant vaccines and the development of new vaccine strategies.

    PubMed

    Nascimento, I P; Leite, L C C

    2012-12-01

    Vaccines were initially developed on an empirical basis, relying mostly on attenuation or inactivation of pathogens. Advances in immunology, molecular biology, biochemistry, genomics, and proteomics have added new perspectives to the vaccinology field. The use of recombinant proteins allows the targeting of immune responses focused against few protective antigens. There are a variety of expression systems with different advantages, allowing the production of large quantities of proteins depending on the required characteristics. Live recombinant bacteria or viral vectors effectively stimulate the immune system as in natural infections and have intrinsic adjuvant properties. DNA vaccines, which consist of non-replicating plasmids, can induce strong long-term cellular immune responses. Prime-boost strategies combine different antigen delivery systems to broaden the immune response. In general, all of these strategies have shown advantages and disadvantages, and their use will depend on the knowledge of the mechanisms of infection of the target pathogen and of the immune response required for protection. In this review, we discuss some of the major breakthroughs that have been achieved using recombinant vaccine technologies, as well as new approaches and strategies for vaccine development, including potential shortcomings and risks.

  2. Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats.

    PubMed

    Nguyen, Jacques D; Bremer, Paul T; Ducime, Alex; Creehan, Kevin M; Kisby, Brent R; Taffe, Michael A; Janda, Kim D

    2016-12-09

    Recreational use of substituted cathinones continues to be an emerging public health problem in the United States; cathinone derivatives α-pyrrolidinopentiophenone (α-PVP) and 3,4-methylenedioxypyrovalerone (MDPV), which have been linked to human fatalities and show high potential for abuse liability in animal models, are of particular concern. The objective of this study was to develop an immunotherapeutic strategy for attenuating the effects of α-PVP and MDPV in rats, using drug-conjugate vaccines created to generate antibodies with neutralizing capacity. Immunoconjugates (α-PVP-KLH and MDPV-KLH) or the control carrier protein, keyhole limpet hemocyanin (KLH), were administered to groups (N = 12) of male Sprague-Dawley rats on Weeks 0, 2 and 4. Groups were administered α-PVP or MDPV (0.0, 0.25, 0.5, 1.0, 5.0 mg/kg, i.p.) in acute drug challenges and tested for changes in wheel activity. Increased wheel activity produced by α-PVP or MDPV in the controls was attenuated in the α-PVP-KLH and MDPV-KLH vaccinated groups, respectively. Rectal temperature decreases produced by MDPV in the controls were reduced in duration in the MDPV-KLH vaccine group. A separate group (N = 19) was trained to intravenously self-administer α-PVP (0.05, 0.1 mg/kg/inf) and vaccinated with KLH or α-PVP-KLH, post-acquisition. Self-administration in α-PVP-KLH rats was initially higher than in the KLH rats but then significantly decreased following a final vaccine booster, unlike the stable intake of KLH rats. The data demonstrate that active vaccination provides functional protection against the effects of α-PVP and MDPV, in vivo, and recommend additional development of vaccines as potential therapeutics for mitigating the effects of designer cathinone derivatives.

  3. Next-generation dengue vaccines: novel strategies currently under development.

    PubMed

    Durbin, Anna P; Whitehead, Stephen S

    2011-10-01

    Dengue has become the most important arboviral infection worldwide with more than 30 million cases of dengue fever estimated to occur each year. The need for a dengue vaccine is great and several live attenuated dengue candidate vaccines are proceeding through clinical evaluation. The need to induce a balanced immune response against all four DENV serotypes with a single vaccine has been a challenge for dengue vaccine developers. A live attenuated DENV chimeric vaccine produced by Sanofi Pasteur has recently entered Phase III evaluation in numerous dengue-endemic regions of the world. Viral interference between serotypes contained in live vaccines has required up to three doses of the vaccine be given over a 12-month period of time. For this reason, novel DENV candidate vaccines are being developed with the goal of achieving a protective immune response with an immunization schedule that can be given over the course of a few months. These next-generation candidates include DNA vaccines, recombinant adenovirus vectored vaccines, alphavirus replicons, and sub-unit protein vaccines. Several of these novel candidates will be discussed.

  4. A live attenuated vaccine prevents replication and transmission of H7N9 virus in mammals

    PubMed Central

    Kong, Huihui; Zhang, Qianyi; Gu, Chunyang; Shi, Jianzhong; Deng, Guohua; Ma, Shujie; Liu, Jinxiong; Chen, Pucheng; Guan, Yuntao; Jiang, Yongping; Chen, Hualan

    2015-01-01

    The continued spread of the newly emerged H7N9 viruses among poultry in China, together with the emergence of drug-resistant variants and the possibility of human-to-human transmission, has spurred attempts to develop an effective vaccine. An MF59-adjuvant H7N9 inactivated vaccine is reported to be well-tolerated and immunogenic in humans; however a study in ferrets indicated that while a single dose of the inactivated H7N9 vaccine reduced disease severity, it did not prevent virus replication and transmission. In this study, we used reverse genetics to produce a cold-adapted, live attenuated H7N9 vaccine (H7N9/AAca) that contains wild-type HA and NA genes from AH/1, and the backbone of the cold-adapted influenza H2N2 A/Ann Arbor/6/60 virus (AAca). H7N9/AAca was attenuated in mice and ferrets, and induced robust neutralizing antibody responses in rhesus mice, ferrets, and guinea pigs immunized once or twice intranasally. The animals immunized twice were completely protected from H7N9 virus challenge. Importantly, the animals vaccinated once were fully protected from transmission when exposed to or in contact with the H7N9 virus-inoculated animals. These results demonstrate that a cold-adapted H7N9 vaccine can prevent H7N9 virus transmission; they provide a compelling argument for further testing of this vaccine in human trials. PMID:26058711

  5. Vaccination against canine distemper virus infection in infant ferrets with and without maternal antibody protection, using recombinant attenuated poxvirus vaccines.

    PubMed

    Welter, J; Taylor, J; Tartaglia, J; Paoletti, E; Stephensen, C B

    2000-07-01

    Canine distemper virus (CDV) infection of ferrets is clinically and immunologically similar to measles, making this a useful model for the human disease. The model was used to determine if parenteral or mucosal immunization of infant ferrets at 3 and 6 weeks of age with attenuated vaccinia virus (NYVAC) or canarypox virus (ALVAC) vaccine strains expressing the CDV hemagglutinin (H) and fusion (F) protein genes (NYVAC-HF and ALVAC-HF) would induce serum neutralizing antibody and protect against challenge infection at 12 weeks of age. Ferrets without maternal antibody that were vaccinated parenterally with NYVAC-HF (n = 5) or ALVAC-HF (n = 4) developed significant neutralizing titers (log(10) inverse mean titer +/- standard deviation of 2.30 +/- 0.12 and 2.20 +/- 0.34, respectively) by the day of challenge, and all survived with no clinical or virologic evidence of infection. Ferrets without maternal antibody that were vaccinated intranasally (i.n.) developed lower neutralizing titers, with NYVAC-HF producing higher titers at challenge (1.11 +/- 0.57 versus 0.40 +/- 0.37, P = 0.02) and a better survival rate (6/7 versus 0/5, P = 0.008) than ALVAC-HF. Ferrets with maternal antibody that were vaccinated parenterally with NYVAC-HF (n = 7) and ALVAC-HF (n = 7) developed significantly higher antibody titers (1.64 +/- 0. 54 and 1.28 +/- 0.40, respectively) than did ferrets immunized with an attenuated CDV vaccine (0.46 +/- 0.59; n = 7) or the recombinant vectors expressing rabies glycoprotein (RG) (0.19 +/- 0.32; n = 8, P = 7 x 10(-6)). The NYVAC vaccine also protected against weight loss, and both the NYVAC and attenuated CDV vaccines protected against the development of some clinical signs of infection, although survival in each of the three vaccine groups was low (one of seven) and not significantly different from the RG controls (none of eight). Combined i.n.-parenteral immunization of ferrets with maternal antibody using NYVAC-HF (n = 9) produced higher titers (1

  6. Immunogenicity and Safety of a Live Attenuated Zoster Vaccine (ZOSTAVAX™) in Korean Adults.

    PubMed

    Choi, Won Suk; Choi, Jung-Hyun; Choi, Jun Yong; Eom, Joong Sik; Kim, Sang Il; Pai, Hyunjoo; Peck, Kyong Ran; Sohn, Jang Wook; Cheong, Hee Jin

    2016-01-01

    A live attenuated zoster vaccine (ZOSTAVAX™, Merck & Co., Inc.) was approved by the Korea Ministry of Food and Drug Safety in 2009. However, the immunogenicity and safety of the vaccine has not been assessed in Korean population. This is multi-center, open-label, single-arm study performed with 180 healthy Korean adults ≥ 50 yr of age. The geometric mean titer (GMT) and geometric mean fold rise (GMFR) of varicella zoster virus (VZV) antibodies were measured by glycoprotein enzyme-linked immunosorbent assay (gpELISA) at 4 weeks post-vaccination. Subjects were followed for exposure to varicella or herpes zoster (HZ), the development of any varicella/varicella-like or HZ/HZ-like rashes, and any other clinical adverse experiences (AEs) for 42 days post-vaccination. For the 166 subjects included in the per-protocol population, the GMT at Day 1 was 66.9. At 4 weeks post-vaccination, the GMT for this population was 185.4, with a GMFR of 2.8 (95% CI, 2.5-3.1). Of the 180 subjects vaccinated, 62.8% experienced ≥ 1 AE, with 53.3% of subjects reporting injection-site AEs. The most frequently reported injection-site AEs were erythema (45.0%) with the majority being mild in intensity. Overall, 44 (24.4%) subjects experienced ≥ 1 systemic AE, 10 (5.5%) subjects experienced a systemic vaccine-related AE, and 3 (1.7%) subjects experienced ≥ 1 serious AE not related to vaccine. No subjects reported a VZV-like rash. There was no subject of death and no subject discontinued due to an adverse event. A single dose of zoster vaccine induced VZV-specific gpELISA antibody response and was generally well-tolerated in healthy Korean adults ≥50 yr of age (registry at www.clinicaltrial.gov No. NCT01556451).

  7. Development of dengue DNA vaccines.

    PubMed

    Danko, Janine R; Beckett, Charmagne G; Porter, Kevin R

    2011-09-23

    Vaccination with plasmid DNA against infectious pathogens including dengue is an active area of investigation. By design, DNA vaccines are able to elicit both antibody responses and cellular immune responses capable of mediating long-term protection. Great technical improvements have been made in dengue DNA vaccine constructs and trials are underway to study these in the clinic. The scope of this review is to highlight the rich history of this vaccine platform and the work in dengue DNA vaccines accomplished by scientists at the Naval Medical Research Center. This work resulted in the only dengue DNA vaccine tested in a clinical trial to date. Additional advancements paving the road ahead in dengue DNA vaccine development are also discussed.

  8. Characterization of Francisella tularensis Schu S4 defined mutants as live-attenuated vaccine candidates.

    PubMed

    Santiago, Araceli E; Mann, Barbara J; Qin, Aiping; Cunningham, Aimee L; Cole, Leah E; Grassel, Christen; Vogel, Stefanie N; Levine, Myron M; Barry, Eileen M

    2015-08-01

    Francisella tularensis (Ft), the etiological agent of tularemia and a Tier 1 select agent, has been previously weaponized and remains a high priority for vaccine development. Ft tularensis (type A) and Ft holarctica (type B) cause most human disease. We selected six attenuating genes from the live vaccine strain (LVS; type B), F. novicida and other intracellular bacteria: FTT0507, FTT0584, FTT0742, FTT1019c (guaA), FTT1043 (mip) and FTT1317c (guaB) and created unmarked deletion mutants of each in the highly human virulent Ft strain Schu S4 (Type A) background. FTT0507, FTT0584, FTT0742 and FTT1043 Schu S4 mutants were not attenuated for virulence in vitro or in vivo. In contrast, Schu S4 gua mutants were unable to replicate in murine macrophages and were attenuated in vivo, with an i.n. LD50 > 10(5) CFU in C57BL/6 mice. However, the gua mutants failed to protect mice against lethal challenge with WT Schu S4, despite demonstrating partial protection in rabbits in a previous study. These results contrast with the highly protective capacity of LVS gua mutants against a lethal LVS challenge in mice, and underscore differences between these strains and the animal models in which they are evaluated, and therefore have important implications for vaccine development.

  9. Innate and adaptive immune control of genetically engineered live-attenuated arenavirus vaccine prototypes.

    PubMed

    Pinschewer, Daniel D; Flatz, Lukas; Steinborn, Ralf; Horvath, Edit; Fernandez, Marylise; Lutz, Hans; Suter, Mark; Bergthaler, Andreas

    2010-09-01

    Arenaviruses such as Lassa virus (LASV) cause significant morbidity and mortality in endemic areas. Using a glycoprotein (GP) exchange strategy, we have recently developed live-attenuated arenavirus vaccine prototypes (rLCMV/VSVG) based on lymphocytic choriomeningitis virus (LCMV), a close relative of LASV. rLCMV/VSVG induced long-term CD8(+) T cell immunity against wild-type virus challenge and exhibited a stably attenuated phenotype in vivo. Here we elucidated the innate and adaptive immune requirements for the control of rLCMV/VSVG. Infection of RAG(-/-) mice resulted in persisting viral RNA in blood but not in overt viremia. The latter was only found in mice lacking both RAG and IFN type I receptor. Conversely, absence of IFN type II signaling or NK cells on an RAG-deficient background had only minor effects on vaccine virus load or none at all. rLCMV/VSVG infection of wild-type mice induced less type I IFN than did wild-type LCMV, and type I as well as type II IFNs were dispensable for the induction of virus-specific memory CD8 T cells and virus-neutralizing antibodies by rLCMV/VSVG. In conclusion, the adaptive immune systems are essential for elimination of rLCMV/VSVG, and type I but not type II IFN plays a major contributive role in lowering rLCMV/VSVG loads in vivo, attesting to the attenuation profile of the vaccine. Nevertheless, IFNs are not required for the induction of potent vaccine responses. These results provide a better understanding of the immunobiology of rLCMV/VSVG and will contribute to the further development of GP exchange vaccines for combating arenaviral hemorrhagic fevers.

  10. A peptide vaccine targeting angiotensin II attenuates the cardiac dysfunction induced by myocardial infarction

    PubMed Central

    Watanabe, Ryo; Suzuki, Jun-ichi; Wakayama, Kouji; Maejima, Yasuhiro; Shimamura, Munehisa; Koriyama, Hiroshi; Nakagami, Hironori; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Morishita, Ryuichi; Komuro, Issei; Isobe, Mitsuaki

    2017-01-01

    A peptide vaccine targeting angiotensin II (Ang II) was recently developed as a novel treatment for hypertension to resolve the problem of noncompliance with pharmacotherapy. Ang II plays a crucial role in the pathogenesis of cardiac remodeling after myocardial infarction (MI), which causes heart failure. In the present study, we examined whether the Ang II vaccine is effective in preventing heart failure. The injection of the Ang II vaccine in a rat model of MI attenuated cardiac dysfunction in association with an elevation in the serum anti-Ang II antibody titer. Furthermore, any detrimental effects of the Ang II vaccine were not observed in the rats that underwent sham operations. Treatment with immunized serum from Ang II vaccine-injected rats significantly suppressed post-MI cardiac dysfunction in MI rats and Ang II-induced remodeling-associated signaling in cardiac fibroblasts. Thus, our present study demonstrates that the Ang II vaccine may provide a promising novel therapeutic strategy for preventing heart failure. PMID:28266578

  11. Approaches towards the development of a vaccine against tuberculosis: recombinant BCG and DNA vaccine.

    PubMed

    Nor, Norazmi Mohd; Musa, Mustaffa

    2004-01-01

    The last few years have witnessed intense research on vaccine development against tuberculosis. This has been driven by the upsurge of tuberculosis cases globally, especially those caused by multi-drug-resistant Mycobacterium tuberculosis strains. Various vaccine strategies are currently being developed which can be broadly divided into the so-called living and non-living vaccines. Examples are attenuated members of the M. tuberculosis complex, recombinant mycobacteria, subunit proteins and DNA vaccines. Given current developments, we anticipate that recombinant BCG and DNA vaccines are the most promising. Multiple epitopes of M. tuberculosis may need to be cloned in a vaccine construct for the desired efficacy to be achieved. The technique of assembly polymerase chain reaction could facilitate such a cloning procedure.

  12. Leishmaniasis: Current Status of Vaccine Development

    PubMed Central

    Handman, Emanuela

    2001-01-01

    Leishmaniae are obligatory intracellular protozoa in mononuclear phagocytes. They cause a spectrum of diseases, ranging in severity from spontaneously healing skin lesions to fatal visceral disease. Worldwide, there are 2 million new cases each year and 1/10 of the world's population is at risk of infection. To date, there are no vaccines against leishmaniasis and control measures rely on chemotherapy to alleviate disease and on vector control to reduce transmission. However, a major vaccine development program aimed initially at cutaneous leishmaniasis is under way. Studies in animal models and humans are evaluating the potential of genetically modified live attenuated vaccines, as well as a variety of recombinant antigens or the DNA encoding them. The program also focuses on new adjuvants, including cytokines, and delivery systems to target the T helper type 1 immune responses required for the elimination of this intracellular organism. The availability, in the near future, of the DNA sequences of the human and Leishmania genomes will extend the vaccine program. New vaccine candidates such as parasite virulence factors will be identified. Host susceptibility genes will be mapped to allow the vaccine to be targeted to the population most in need of protection. PMID:11292637

  13. Vaccinia viruses with mutations in the E3L gene as potential replication-competent, attenuated vaccines: intra-nasal vaccination.

    PubMed

    Vijaysri, Sangeetha; Jentarra, Garilyn; Heck, Michael C; Mercer, Andrew A; McInnes, Colin J; Jacobs, Bertram L

    2008-01-30

    Vaccinia virus (VACV) has been used as the vaccine to protect against smallpox, and recombinant VACVs have been used to develop vaccine candidates against numerous cancers and infectious diseases. Although relatively safe for use in humans, the strains of VACV that were used as smallpox vaccines led to several complications including, progressive infection in immune compromised individuals, eczema vaccination in individuals with a history of atopic dermatitis, and encephalitis and perimyocarditis in apparently healthy individuals. The work described in this paper focuses on attenuated strains of VACV that may have the potential for use as vaccine vectors with reduced pathogenicity. We have generated several VACV mutants in a WR background with specific mutations in the E3L gene that were at least a 1000-fold less pathogenic compared to wtVACV upon intra-nasal infection of mice. Many of these mutant viruses replicated to high titers in the nasal mucosa of mice following intra-nasal administration. Despite replication to high titers in the nose, there was little spread to other organs in infected animals. Intra-nasal vaccination with doses as low as 100-1000 pfu (plaque forming units) of these replicating VACV constructs were sufficient to protect the host from challenge with large doses of wtVACV. Similar constructs in a Copenhagen and a NYCBH background were highly attenuated, yet effective as vaccines in the mouse model. These recombinant VACV constructs may be promising vector candidates for use in vaccination strategies against smallpox and other pathogens.

  14. A genetically engineered live attenuated vaccine of Coccidioides posadasii protects BALB/c mice against coccidioidomycosis.

    PubMed

    Xue, Jianmin; Chen, Xia; Selby, Dale; Hung, Chiung-Yu; Yu, Jieh-Juen; Cole, Garry T

    2009-08-01

    Coccidioidomycosis (also known as San Joaquin Valley fever) is an occupational disease. Workers exposed to outdoor dust which contains spores of the soil-inhabiting fungus have a significantly increased risk of respiratory infection. In addition, people with compromised T-cell immunity, the elderly, and certain racial groups, particularly African-Americans and Filipinos, who live in regions of endemicity in the southwestern United States have an elevated incidence of symptomatic infection caused by inhalation of spores of Coccidioides posadasii or Coccidioides immitis. Recurring epidemics and escalation of medical costs have helped to motivate production of a vaccine against valley fever. The major focus has been the development of a defined, T-cell-reactive, recombinant protein vaccine. However, none of the products described to date have provided full protection to coccidioidal disease-susceptible BALB/c mice. Here we describe the first genetically engineered, live, attenuated vaccine that protects both BALB/c and C57BL/6 mice against coccidioidomycosis. Two chitinase genes (CTS2 and CTS3) were disrupted to yield the attenuated strain, which was unable to endosporulate and was no longer infectious. Vaccinated survivors mounted an immune response characterized by production of both T-helper-1- and T-helper-2-type cytokines. Histology revealed well-formed granulomas and markedly diminished inflammation. Significantly fewer organisms were observed in the lungs of survivors than in those of nonvaccinated mice. Additional investigations are required to further define the nature of the live, attenuated vaccine-induced immunity against Coccidioides infection.

  15. Enhanced expression of HIV and SIV vaccine antigens in the structural gene region of live attenuated rubella viral vectors and their incorporation into virions.

    PubMed

    Virnik, Konstantin; Ni, Yisheng; Berkower, Ira

    2013-04-19

    Despite the urgent need for an HIV vaccine, its development has been hindered by virus variability, weak immunogenicity of conserved epitopes, and limited durability of the immune response. For other viruses, difficulties with immunogenicity were overcome by developing live attenuated vaccine strains. However, there is no reliable method of attenuation for HIV, and an attenuated strain would risk reversion to wild type. We have developed rubella viral vectors, based on the live attenuated vaccine strain RA27/3, which are capable of expressing important HIV and SIV vaccine antigens. The rubella vaccine strain has demonstrated safety, immunogenicity, and long lasting protection in millions of children. Rubella vectors combine the growth and immunogenicity of live rubella vaccine with the antigenicity of HIV or SIV inserts. This is the first report showing that live attenuated rubella vectors can stably express HIV and SIV vaccine antigens at an insertion site located within the structural gene region. Unlike the Not I site described previously, the new site accommodates a broader range of vaccine antigens without interfering with essential viral functions. In addition, antigens expressed at the structural site were controlled by the strong subgenomic promoter, resulting in higher levels and longer duration of antigen expression. The inserts were expressed as part of the structural polyprotein, processed to free antigen, and incorporated into rubella virions. The rubella vaccine strain readily infects rhesus macaques, and these animals will be the model of choice for testing vector growth in vivo and immunogenicity.

  16. Latest developments and future directions in dengue vaccines

    PubMed Central

    Thisyakorn, Chule

    2014-01-01

    Dengue is a mosquito-borne disease which is currently an expanding global health problem. The disease is caused by four closely related viruses, the dengue virus. There are no specific dengue therapeutics and prevention is currently limited to vector control measures. Development of an effective tetravalent dengue vaccine would therefore represent a major advance in the control of the disease and is considered a high public health priority. While a licensed dengue vaccine is not yet available, the scope and intensity of dengue vaccine development has increased dramatically in the last decade. The uniqueness of the dengue viruses and the spectrum of disease resulting from infection have made dengue vaccine development difficult. Several vaccine candidates are currently being evaluated in clinical studies. The candidate currently at the most advanced clinical development stage, a live-attenuated tetravalent vaccine based on chimeric yellow fever dengue virus, has progressed to phase III efficacy studies. Several other live-attenuated vaccines, as well as subunit, DNA and purified inactivated vaccine candidates, are at earlier stages of clinical development. Additional technological approaches, such as virus-vectored and virus-like particle-based vaccines, are under evaluation in preclinical studies. PMID:24757522

  17. [Possibilities and limitations in veterinary vaccine development using the example of classical swine fever].

    PubMed

    Blome, Sandra; Gabriel, Claudia; Beer, Martin

    2013-01-01

    The use of vaccines is still one of the most effective tools to control infectious diseases. Up to now, conventional vaccines are employed in the majority of cases. Drawbacks of these established vaccines include the lack of differentiability of infected from vaccinated animals (DIVA or marker strategy), limitations in the efficacy spectrum, and constraints and restrictions in production. For this reason, new vaccines, which do not show these disadvantages, are under development, especially for notifiable diseases such as classical swine fever (CSF). In principle, the following modern vaccine types can be differentiated: recombinant attenuated vaccines, recombinant inactivated vaccines or subunit vaccines, vector vaccines, and DNA/ RNA vaccines. During the last years, especially attenuated deletion vaccines or chimeric constructs have shown potential. Under field conditions, all marker vaccines have to be accompanied by a potent test system. Particularly this point often shows weaknesses. Alternative vaccine candidates are so far only prototypes and licensing is only a medium term possibility. Moreover, most of these vaccines are genetically engineered and can be problematic in terms of licensing and the public's acceptance. In conclusion, conventional vaccines still present the standard, especially in terms of efficacy. Yet, only vaccines with DIVA properties are feasible for the control of CSF. Thus, development and assessment of alternative vaccines is of paramount importance. The present overview summarizes concepts and vaccine types using the example of classical swine fever. It also recapitulates their advantages and disadvantages as well as their limitations.

  18. Live Attenuated and Inactivated Influenza Vaccines in Children

    PubMed Central

    Ilyushina, Natalia A.; Haynes, Brenda C.; Hoen, Anne G.; Khalenkov, Alexey M.; Housman, Molly L.; Brown, Eric P.; Ackerman, Margaret E.; Treanor, John J.; Luke, Catherine J.; Subbarao, Kanta; Wright, Peter F.

    2015-01-01

    Background. Live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) are available for children. Local and systemic immunity induced by LAIV followed a month later by LAIV and IIV followed by LAIV were investigated with virus recovery after LAIV doses as surrogates for protection against influenza on natural exposure. Methods. Fifteen children received IIV followed by LAIV, 13 an initial dose of LAIV, and 11 a second dose of LAIV. The studies were done during autumn 2009 and autumn 2010 with the same seasonal vaccine (A/California/07/09 [H1N1], A/Perth/16/09 [H3N2], B/Brisbane/60/08). Results. Twenty-eight of 39 possible influenza viral strains were recovered after the initial dose of LAIV. When LAIV followed IIV, 21 of 45 viral strains were identified. When compared to primary LAIV infection, the decreased frequency of shedding with the IIV-LAIV schedule was significant (P = .023). With LAIV-LAIV, the fewest viral strains were recovered (3/33)—numbers significantly lower (P < .001) than shedding after initial LAIV and after IIV-LAIV (P < .001). Serum hemagglutination inhibition antibody responses were more frequent after IIV than LAIV (P = .02). In contrast, more mucosal immunoglobulin A responses were seen with LAIV. Conclusions. LAIV priming induces greater inhibition of virus recovery on LAIV challenge than IIV priming. The correlate(s) of protection are the subject of ongoing analysis. Clinical Trials Registration. NCT01246999. PMID:25165161

  19. Development of Burkholderia mallei and pseudomallei vaccines.

    PubMed

    Silva, Ediane B; Dow, Steven W

    2013-01-01

    Burkholderia mallei and Burkholderia pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. Chronic infection may develop after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult. B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms, and infection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88, and pro-inflammatory cytokines such as IFN-γ and TNF-α play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for both microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently development of Burkholderia vaccines has received renewed attention. This review will summarize current and past approaches to develop B. mallei and B. pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines. Subunit

  20. Gentamicin-Attenuated Leishmania infantum Vaccine: Protection of Dogs against Canine Visceral Leishmaniosis in Endemic Area of Southeast of Iran

    PubMed Central

    Daneshvar, Hamid; Namazi, Mohammad Javad; Kamiabi, Hossein; Burchmore, Richard; Cleaveland, Sarah; Phillips, Stephen

    2014-01-01

    An attenuated line of Leishmania infantum (L. infantum H-line) has been established by culturing promastigotes in vitro under gentamicin pressure. A vaccine trial was conducted using 103 naive dogs from a leishmaniosis non-endemic area (55 vaccinated and 48 unvaccinated) brought into an endemic area of southeast Iran. No local and/or general indications of disease were observed in the vaccinated dogs immediately after vaccination. The efficacy of the vaccine was evaluated after 24 months (4 sandfly transmission seasons) by serological, parasitological analyses and clinical examination. In western blot analysis of antibodies to L. infantum antigens, sera from 10 out of 31 (32.2%) unvaccinated dogs, but none of the sera from vaccinated dogs which were seropositive at >100, recognized the 21 kDa antigen of L. infantum wild-type (WT). Nine out of 31 (29%) unvaccinated dogs, but none of vaccinated dogs, were positive for the presence of Leishmania DNA. One out of 46 (2.2%) vaccinated dogs and 9 out of 31 (29%) unvaccinated dogs developed clinical signs of disease. These results suggest that gentamicin-attenuated L. infantum induced a significant and strong protective effect against canine visceral leishmaniosis in the endemic area. PMID:24743691

  1. Vaccine Development for Zika Virus-Timelines and Strategies.

    PubMed

    Durbin, Anna P

    2016-09-01

    Zika virus is a mosquito-borne Flavivirus that spread rapidly through South and Central America in 2015 to 2016. Microcephaly has been causally associated with Zika virus infection during pregnancy and the World Health Organization declared Zika virus as a Public Health Emergency of International Concern. To address this crisis, many groups have expressed their commitment to developing a Zika virus vaccine. Different strategies for Zika virus vaccine development are being considered including recombinant live attenuated vaccines, purified inactivated vaccines (PIVs), DNA vaccines, and viral vectored vaccines. Important to Zika virus vaccine development will be the target group chosen for vaccination and which end point(s) is chosen for efficacy determination. The first clinical trials of Zika virus vaccine candidates will begin in Q3/4 2016 but the pathway to licensure for a Zika virus vaccine is expected to take several years. Efforts are ongoing to accelerate Zika virus vaccine development and evaluation with the ultimate goal of reducing time to licensure.

  2. Dengue vaccines: challenges, development, current status and prospects.

    PubMed

    Ghosh, A; Dar, L

    2015-01-01

    Infection with dengue virus (DENV) is the most rapidly spreading mosquito-borne viral disease in the world. The clinical spectrum of dengue, caused by any of the four serotypes of DENV, ranges from mild self-limiting dengue fever to severe dengue, in the form dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Increased rates of hospitalization due to severe dengue, during outbreaks, result in massive economic losses and strained health services. In the absence of specific antiviral therapy, control of transmission of DENV by vector management is the sole method available for decreasing dengue-associated morbidity. Since vector control strategies alone have not been able to satisfactorily achieve reduction in viral transmission, the implementation of a safe, efficacious and cost-effective dengue vaccine as a supplementary measure is a high public health priority. However, the unique and complex immunopathology of dengue has complicated vaccine development. Dengue vaccines have also been challenged by critical issues like lack of animal models for the disease and absence of suitable markers of protective immunity. Although no licensed dengue vaccine is yet available, several vaccine candidates are under phases of development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, subunit vaccines, DNA vaccines and viral-vectored vaccines. Although some vaccine candidates have progressed from animal trials to phase II and III in humans, a number of issues regarding implementation of dengue vaccine in countries like India still need to be addressed. Despite the current limitations, collaborative effects of regulatory bodies like World Health Organization with vaccine manufacturers and policy makers, to facilitate vaccine development and standardize field trials can make a safe and efficacious dengue vaccine a reality in near future.

  3. The yellow fever 17D virus as a platform for new live attenuated vaccines.

    PubMed

    Bonaldo, Myrna C; Sequeira, Patrícia C; Galler, Ricardo

    2014-01-01

    The live-attenuated yellow fever 17D virus is one of the most outstanding human vaccines ever developed. It induces efficacious immune responses at a low production cost with a well-established manufacture process. These advantages make the YF17D virus attractive as a vector for the development of new vaccines. At the beginning of vector development studies, YF17D was genetically manipulated to express other flavivirus prM and E proteins, components of the viral envelope. While these 17D recombinants are based on the substitution of equivalent YF17D genes, other antigens from unrelated pathogens have also been successfully expressed and delivered by recombinant YF17D viruses employing alternative strategies for genetic manipulation of the YF17D genome. Herein, we discuss these strategies in terms of possibilities of single epitope or larger sequence expression and the main properties of these replication-competent viral platforms.

  4. Development of a schistosomiasis vaccine.

    PubMed

    Molehin, Adebayo J; Rojo, Juan U; Siddiqui, Sabrina Z; Gray, Sean A; Carter, Darrick; Siddiqui, Afzal A

    2016-05-01

    Schistosomiasis is a neglected tropical disease (NTD) of public health importance. Despite decades of implementation of mass praziquantel therapy programs and other control measures, schistosomiasis has not been contained and continues to spread to new geographic areas. A schistosomiasis vaccine could play an important role as part of a multifaceted control approach. With regards to vaccine development, many biological bottlenecks still exist: the lack of reliable surrogates of protection in humans; immune interactions in co-infections with other diseases in endemic areas; the potential risk of IgE responses to antigens in endemic populations; and paucity of appropriate vaccine efficacy studies in nonhuman primate models. Research is also needed on the role of modern adjuvants targeting specific parts of the innate immune system to tailor a potent and protective immune response for lead schistosome vaccine candidates with the long-term aim to achieve curative worm reduction. This review summarizes the current status of schistosomiasis vaccine development.

  5. Efficacy and effectiveness of live attenuated influenza vaccine in school-age children.

    PubMed

    Coelingh, Kathleen; Olajide, Ifedapo Rosemary; MacDonald, Peter; Yogev, Ram

    2015-01-01

    Evidence of high efficacy of live attenuated influenza vaccine (LAIV) from randomized controlled trials is strong for children 2-6 years of age, but fewer data exist for older school-age children. We reviewed the published data on efficacy and effectiveness of LAIV in children ≥5 years. QUOSA (Elsevier database) was searched for articles published from January 1990 to June 2014 that included 'FluMist', 'LAIV', 'CAIV', 'cold adapted influenza vaccine', 'live attenuated influenza vaccine', 'live attenuated cold adapted' or 'flu mist'. Studies evaluated included randomized controlled trials, effectiveness and indirect protection studies. This review demonstrates that LAIV has considerable efficacy and effectiveness in school-age children.

  6. Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens.

    PubMed

    Pei, Yanlong; Parreira, Valeria R; Roland, Kenneth L; Curtiss, Roy; Prescott, John F

    2014-01-01

    Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors.

  7. Suppressing active replication of a live attenuated simian immunodeficiency virus vaccine does not abrogate protection from challenge

    SciTech Connect

    Gabriel, Benjamin; Fiebig, Uwe; Hohn, Oliver; Plesker, Roland; Coulibaly, Cheick; Cichutek, Klaus; Mühlebach, Michael D.; Bannert, Norbert; Kurth, Reinhard; Norley, Stephen

    2016-02-15

    Although safety concerns preclude the use of live attenuated HIV vaccines in humans, they provide a useful system for identifying the elusive correlates of protective immunity in the SIV/macaque animal model. However, a number of pieces of evidence suggest that protection may result from prior occupancy of susceptible target cells by the vaccine virus rather than the immune response. To address this, we developed a Nef-deletion variant of an RT-SHIV whose active replication could be shut off by treatment with RT-inhibitors. Groups of macaques were inoculated with the ∆Nef-RT-SHIV and immune responses allowed to develop before antiretroviral treatment and subsequent challenge with wild-type SIVmac239. Vaccinated animals either resisted infection fully or significantly controlled the subsequent viremia. However, there was no difference between animals undergoing replication of the vaccine virus and those without. This strongly suggests that competition for available target cells does not play a role in protection. - Highlights: • A Nef-deleted RT-SHIV was used as a live attenuated vaccine in macaques. • Vaccine virus replication was shut down to investigate its role in protection. • Ongoing vaccine virus replication did not appear to be necessary for protection. • An analysis of T- and B-cell responses failed to identify a correlate of protection.

  8. Evaluation in mice of Brucella ovis attenuated mutants for use as live vaccines against B. ovis infection.

    PubMed

    Sancho, Pilar; Tejedor, Carmen; Sidhu-Muñoz, Rebeca S; Fernández-Lago, Luis; Vizcaíno, Nieves

    2014-06-04

    Brucella ovis causes ram contagious epididymitis, a disease for which a specific vaccine is lacking. Attenuated Brucella melitensis Rev 1, used as vaccine against ovine and caprine brucellosis caused by B. melitensis, is also considered the best vaccine available for the prophylaxis of B. ovis infection, but its use for this purpose has serious drawbacks. In this work, two previously characterized B. ovis attenuated mutants (Δomp25d and Δomp22) were evaluated in mice, in comparison with B. melitensis Rev 1, as vaccines against B. ovis. Similarities, but also significant differences, were found regarding the immune response induced by the three vaccines. Mice vaccinated with the B. ovis mutants developed anti-B. ovis antibodies in serum of the IgG1, IgG2a and IgG2b subclasses and their levels were higher than those observed in Rev 1-vaccinated mice. After an antigen stimulus with B. ovis cells, splenocytes obtained from all vaccinated mice secreted similar levels of TNF-α and IL12(p40) and remarkably high amounts of IFN-γ, a crucial cytokine in protective immunity against other Brucella species. By contrast, IL-1α -an enhancer of T cell responses to antigen- was present at higher levels in mice vaccinated with the B. ovis mutants, while IL-10, an anti-inflammatory cytokine, was significantly more abundant in Rev 1-vaccinated mice. Additionally, the B. ovis mutants showed appropriate persistence, limited splenomegaly and protective efficacy against B. ovis similar to that observed with B. melitensis Rev 1. These characteristics encourage their evaluation in the natural host as homologous vaccines for the specific prophylaxis of B. ovis infection.

  9. Development of Recombinant Arenavirus-Based Vaccines.

    PubMed

    Martínez-Sobrido, Luis; de la Torre, Juan Carlos

    2017-01-01

    The development of arenavirus reverse genetics has provided investigators with a novel and powerful approach for the investigation of the arenavirus molecular and cell biology. The use of cell-based minigenome systems has allowed examining the cis- and trans-acting factors involved in arenavirus replication and transcription, and the identification of novel anti-arenaviral drug targets without requiring the use of live forms of arenaviruses. Likewise, it is now feasible to rescue infectious arenaviruses entirely from cloned cDNAs containing predetermined mutations in their genomes to investigate virus-host interactions and mechanisms of pathogenesis. These advances in arenavirus genetics have also facilitated screens to identify anti-arenaviral drugs and the pursuit of novel strategies to generate live-attenuated arenavirus vaccine candidates. Moreover, the generation of tri-segmented (r3) arenaviruses expressing foreign genes of interest (GOI) has opened the possibility of implementing live-attenuated arenaviruses-based vaccine vector approaches. In this chapter, we will summarize the implementation of plasmid-based reverse genetics techniques for the development of r3 arenaviruses expressing foreign GOI for their implementation as vaccine vectors.

  10. Live Attenuated S. Typhimurium Vaccine with Improved Safety in Immuno-Compromised Mice

    PubMed Central

    Periaswamy, Balamurugan; Maier, Lisa; Vishwakarma, Vikalp; Slack, Emma; Kremer, Marcus; Andrews-Polymenis, Helene L.; McClelland, Michael; Grant, Andrew J.; Suar, Mrutyunjay; Hardt, Wolf-Dietrich

    2012-01-01

    Live attenuated vaccines are of great value for preventing infectious diseases. They represent a delicate compromise between sufficient colonization-mediated adaptive immunity and minimizing the risk for infection by the vaccine strain itself. Immune defects can predispose to vaccine strain infections. It has remained unclear whether vaccine safety could be improved via mutations attenuating a vaccine in immune-deficient individuals without compromising the vaccine's performance in the normal host. We have addressed this hypothesis using a mouse model for Salmonella diarrhea and a live attenuated Salmonella Typhimurium strain (ssaV). Vaccination with this strain elicited protective immunity in wild type mice, but a fatal systemic infection in immune-deficient cybb−/−nos2−/− animals lacking NADPH oxidase and inducible NO synthase. In cybb−/−nos2−/− mice, we analyzed the attenuation of 35 ssaV strains carrying one additional mutation each. One strain, Z234 (ssaV SL1344_3093), was >1000-fold attenuated in cybb−/−nos2−/− mice and ≈100 fold attenuated in tnfr1−/− animals. However, in wt mice, Z234 was as efficient as ssaV with respect to host colonization and the elicitation of a protective, O-antigen specific mucosal secretory IgA (sIgA) response. These data suggest that it is possible to engineer live attenuated vaccines which are specifically attenuated in immuno-compromised hosts. This might help to improve vaccine safety. PMID:23029007

  11. Anti-cocaine vaccine development

    PubMed Central

    Kinsey, Berma M; Kosten, Thomas R; Orson, Frank M

    2010-01-01

    Cocaine abuse is an ongoing and serious problem which has lead to the growth of a brutal criminal enterprise, particularly in the Americas and Europe. At present, there are no effective pharmacological agents available to treat the addiction by blocking cocaine or reversing its effects. In order to help motivated addicts conquer their addiction, vaccines against cocaine are being developed, and one has progressed to clinical trials. This review will discuss the concept of anti-drug vaccines in general, the successes and limitations of the various anti-cocaine vaccine approaches, the results of the clinical trials with an anti-cocaine vaccine, and some new vaccine-mediated approaches to combat cocaine addiction. PMID:20822352

  12. Evaluation of regulated delayed attenuation strategies for Salmonella enterica serovar Typhi vaccine vectors in neonatal and infant mice.

    PubMed

    Shi, Huoying; Wang, Shifeng; Curtiss, Roy

    2013-06-01

    We developed regulated delayed attenuation strategies for Salmonella vaccine vectors. In this study, we evaluated the combination of these strategies in recombinant attenuated Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium vaccine vectors with similar genetic backgrounds in vitro and in vivo. Our goal is to develop a vaccine to prevent Streptococcus pneumoniae infection in newborns; thus, all strains delivered a pneumococcal antigen PspA and the impact of maternal antibodies was evaluated. The results showed that all strains with the regulated delayed attenuated phenotype (RDAP) displayed an invasive ability stronger than that of the S. Typhi vaccine strain, Ty21a, but weaker than that of their corresponding wild-type parental strains. The survival curves of different RDAP vaccine vectors in vitro and in vivo exhibited diverse regulated delayed attenuation kinetics, which was different from S. Typhi Ty21a and the wild-type parental strains. Under the influence of maternal antibody, the persistence of the S. Typhimurium RDAP strain displayed a regulated delayed attenuation trend in nasal lymphoid tissue (NALT), lung, and Peyer's patches, while the persistence of S. Typhi RDAP strains followed the curve only in NALT. The bacterial loads of S. Typhi RDAP strains were lower in NALT, lung, and Peyer's patches in mice born to immune mothers than in those born to naive mothers. In accordance with these results, RDAP vaccine strains induced high titers of IgG antibodies against PspA and against Salmonella lipopolysaccharides. Immunization of mothers with S. Typhi RDAP strains enhanced the level of vaginal mucosal IgA, gamma interferon (IFN-γ), and interleukin 4 (IL-4) and resulted in a higher level of protection against S. pneumoniae challenge.

  13. TB vaccines in clinical development.

    PubMed

    Ginsberg, Ann M; Ruhwald, Morten; Mearns, Helen; McShane, Helen

    2016-08-01

    The 4th Global Forum on TB Vaccines, convened in Shanghai, China, from 21 - 24 April 2015, brought together a wide and diverse community involved in tuberculosis vaccine research and development to discuss the current status of, and future directions for this critical effort. This paper summarizes the sessions on TB Vaccines in Clinical Development, and Clinical Research: Data and Findings. Summaries of all sessions from the 4th Global Forum are compiled in a special supplement of Tuberculosis. [August 2016, Vol 99, Supp S1, S1-S30].

  14. Advances in Antiviral vaccine development

    PubMed Central

    Graham, Barney S.

    2013-01-01

    Summary Antiviral vaccines have been the most successful biomedical intervention for preventing epidemic viral disease. Vaccination for smallpox in humans and rinderpest in cattle was the basis for disease eradication, and recent progress in polio eradication is promising. While early vaccines were developed empirically by passage in live animals or eggs, more recent vaccines have been developed because of the advent of new technologies, particularly cell culture and molecular biology. Recent technological advances in gene delivery and expression, nanoparticles, protein manufacturing, and adjuvants have created the potential for new vaccine platforms that may provide solutions for vaccines against viral pathogens for which no interventions currently exist. In addition, the technological convergence of human monoclonal antibody isolation, structural biology, and high throughput sequencing is providing new opportunities for atomic-level immunogen design. Selection of human monoclonal antibodies can identify immunodominant antigenic sites associated with neutralization and provide reagents for stabilizing and solving the structure of viral surface proteins. Understanding the structural basis for neutralization can guide selection of vaccine targets. Deep sequencing of the antibody repertoire and defining the ontogeny of the desired antibody responses can reveal the junctional recombination and somatic mutation requirements for B-cell recognition and affinity maturation. Collectively, this information will provide new strategic approaches for selecting vaccine antigens, formulations, and regimens. Moreover, it creates the potential for rational vaccine design and establishing a catalogue of vaccine technology platforms that would be effective against any given family or class of viral pathogens and improve our readiness to address new emerging viral threats. PMID:23947359

  15. Construction of two Listeria ivanovii attenuated strains expressing Mycobacterium tuberculosis antigens for TB vaccine purposes.

    PubMed

    Lin, Qingqing; Zhou, Mengying; Xu, Zongkai; Khanniche, Asma; Shen, Hao; Wang, Chuan

    2015-02-20

    Bacillus Calmette-Guerin (BCG) has failed in complete control of tuberculosis (TB), thus, novel tuberculosis vaccines are urgently needed. We have constructed several TB vaccine candidates, which are characterized by the use of Listeria ivanovii (LI) strain as an antigen delivery vector. Two L. ivanovii attenuated recombinant strains L. ivanovii△actAplcB-Rv0129c and L. ivanovii△actAplcB-Rv3875 were successfully screened. Results from genome PCR and sequencing showed that the Mycobacterium tuberculosis antigen gene cassette coding for Ag85C or ESAT-6 protein respectively had been integrated into LI genome downstream of mpl gene. Western blot confirmed the secretion of Ag85C or ESAT-6 protein from the recombinant LI strains. These two recombinant strains showed similar growth curves as wide type strain in vitro. In vivo, they transiently propagated in mice spleen and liver, and induced specific CD8(+) IFN-γ secretion. Therefore, in this paper, two novel LI attenuated strains expressing specific TB antigens were successfully constructed. The promising growth characteristics in mice immune system and the capability of induction of IFN-γ secretion make them of potential interest for development of TB vaccines.

  16. A Reverse Genetics Approach for the Design of Methyltransferase-Defective Live Attenuated Avian Metapneumovirus Vaccines.

    PubMed

    Zhang, Yu; Sun, Jing; Wei, Yongwei; Li, Jianrong

    2016-01-01

    Avian metapneumovirus (aMPV), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and is associated with swollen head syndrome in chickens. aMPV belongs to the family Paramyxoviridae which includes many important human pathogens such as human respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and human parainfluenza virus type 3 (PIV3). The family also includes highly lethal emerging pathogens such as Nipah virus and Hendra virus, as well as agriculturally important viruses such as Newcastle disease virus (NDV). For many of these viruses, there is no effective vaccine. Here, we describe a reverse genetics approach to develop live attenuated aMPV vaccines by inhibiting the viral mRNA cap methyltransferase. The viral mRNA cap methyltransferase is an excellent target for the attenuation of paramyxoviruses because it plays essential roles in mRNA stability, efficient viral protein translation and innate immunity. We have described in detail the materials and methods used to generate recombinant aMPVs that lack viral mRNA cap methyltransferase activity. We have also provided methods to evaluate the genetic stability, pathogenesis, and immunogenicity of live aMPV vaccine candidates in turkeys.

  17. Is HCMV vaccine an unmet need? The state of art of vaccine development.

    PubMed

    Chiurchiu, S; Calo Carducci, F I; Rocchi, F; Simonetti, A; Bonatti, G; Salmaso, S; Melchiorri, D; Pani, L; Rossi, P

    2013-01-01

    Congenital HCMV infection is the most frequent congenital infection, with an incidence of 0.2- 2.5 percent among all live births. About 11 percent of infected newborns show symptoms at birth, including hepato-splenomegaly, thrombocytopenia, neurologic involvement, hearing impairment and visual deficit. Moreover, 5-25 percent of the asymptomatic congenital HCMV-infected neonates will develop sequelae over months or even years. The relevant social burden, the economic costs of pre-natal screening, post-natal diagnosis, follow-up and possible therapy, although still limited, are the major factors to be considered. Several types of vaccines have been explored in order to develop an effective and safe HCMV vaccine: live attenuated, subunit, vectored, peptide, DNA, and subviral ones, but none are available for use. This review illustrates the different vaccine types studied to date, focusing on the possible vaccination strategy to be implemented once the HCMV vaccine is available, in terms of target population.

  18. Spray application of live attenuated F Strain-derived Mycoplasma gallisepticum vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Live attenuated vaccines (LAVs) are commonly utilized to protect commercial table egg producers from economic losses associated with challenges by the respiratory pathogen Mycoplasma gallisepticum (MG). Currently there are four MG LAVs commercially available within the United States. Consistent am...

  19. [Factors of Salmonella typhi virulence in relation to the development of new vaccines].

    PubMed

    García, J A; Paniagua, J; Pelayo, R; Isibasi, A; Kumate, J

    1992-01-01

    Although many vaccines against typhoid fever have been developed, none have been adapted for their further application on developing countries. In order to get better vaccines, the virulence factors of both S. typhi and S. typhimurium have been studied. Thus, some protection assays have been made using surface antigens involved on virulence or using live attenuated vaccines of bacteria mutated on virulence genes. Here we present a brief review about virulence factors studied so far for the development of new vaccines.

  20. A live attenuated Salmonella enterica serovar Typhimurium vaccine provides cross-protection against Salmonella serovars to reduce disease severity and pathogen transmission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A live attenuated Salmonella enterica serovar Typhimurium vaccine was developed to confer broad protection against multiple Salmonella serovars to prevent disease and reduce pathogen colonization and shedding. Two vaccine trials were performed in swine to determine the protection afforded by the vac...

  1. Arenavirus reverse genetics for vaccine development.

    PubMed

    Ortiz-Riaño, Emilio; Cheng, Benson Yee Hin; Carlos de la Torre, Juan; Martínez-Sobrido, Luis

    2013-06-01

    Arenaviruses are important human pathogens with no Food and Drug Administration (FDA)-licensed vaccines available and current antiviral therapy being limited to an off-label use of the nucleoside analogue ribavirin of limited prophylactic efficacy. The development of reverse genetics systems represented a major breakthrough in arenavirus research. However, rescue of recombinant arenaviruses using current reverse genetics systems has been restricted to rodent cells. In this study, we describe the rescue of recombinant arenaviruses from human 293T cells and Vero cells, an FDA-approved line for vaccine development. We also describe the generation of novel vectors that mediate synthesis of both negative-sense genome RNA and positive-sense mRNA species of lymphocytic choriomeningitis virus (LCMV) directed by the human RNA polymerases I and II, respectively, within the same plasmid. This approach reduces by half the number of vectors required for arenavirus rescue, which could facilitate virus rescue in cell lines approved for human vaccine production but that cannot be transfected at high efficiencies. We have shown the feasibility of this approach by rescuing both the Old World prototypic arenavirus LCMV and the live-attenuated vaccine Candid#1 strain of the New World arenavirus Junín. Moreover, we show the feasibility of using these novel strategies for efficient rescue of recombinant tri-segmented both LCMV and Candid#1.

  2. Reversion to virulence and efficacy of an attenuated Canarypox vaccine in Hawai'i 'Amakihi (Hemignathus virens).

    PubMed

    Atkinson, Carter T; Wiegand, Kimberly C; Triglia, Dennis; Jarvi, Susan I

    2012-12-01

    Vaccines may be effective tools for protecting small populations of highly susceptible endangered, captive-reared, or translocated Hawaiian honeycreepers from introduced Avipoxvirus, but their efficacy has not been evaluated. An attenuated Canarypox vaccine that is genetically similar to one of two passerine Avipoxvirus isolates from Hawai'i and distinct from Fowlpox was tested to evaluate whether Hawai'i 'Amakihi (Hemignathus virens) can be protected from wild isolates of Avipoxvirus from the Hawaiian Islands. Thirty-one (31) Hawai'i 'Amakihi were collected from high-elevation habitats on Mauna Kea Volcano, where pox transmission is rare, and randomly divided into two groups. One group was vaccinated with Poximune C, whereas the other group received a sham vaccination with sterile water. Four of 15 (27%) vaccinated birds developed life-threatening disseminated lesions or lesions of unusually long duration, whereas one bird never developed a vaccine-associated lesion or "take." After vaccine lesions healed, vaccinated birds were randomly divided into three groups of five and challenged with either a wild isolate of Fowlpox (FP) from Hawai'i, a Hawai'i 'Amakihi isolate of a Canarypox-like virus (PV1), or a Hawai'i 'Amakihi isolate of a related, but distinct, passerine Avipoxvirus (PV2). Similarly, three random groups of five unvaccinated 'Amakihi were challenged with the same virus isolates. Vaccinated and unvaccinated 'Amakihi challenged with FP had transient infections with no clinical signs of infection. Mortality in vaccinated 'Amakihi challenged with PV1 and PV2 ranged from 0% (0/5) for PV1 to 60% (3/5) for PV2. Mortality in unvaccinated 'Amakihi ranged from 40% (2/5) for PV1 to 100% (5/5) for PV2. Although the vaccine provided some protection against PV1, both potential for vaccine reversion and low efficacy against PV2 preclude its use in captive or wild honeycreepers.

  3. Comparative genomics of the Mycobacterium signaling architecture and implications for a novel live attenuated Tuberculosis vaccine.

    PubMed

    Zhou, Peifu; Xie, Jianping

    2014-01-01

    Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), remains a major threat to global public health. A new TB vaccine affording superior immune protection to M. bovis Bacillus Calmette-Guérin (BCG) is imperative. The advantage of a live attenuated vaccine is that it can mimic the bona fide pathogen, elicit immune responses similar to natural infection, and potentially provide more protection than other vaccines. BCG, the only vaccine and a live attenuated vaccine that is the result of cumulative mutations by serial passage of M. bovis, has provided clues for the construction of novel improved vaccines. A strategy is put forward for identifying a new live attenuated TB vaccine generated by cumulative mutation based on M.tb. Given the important role of the M.tb signaling network consisting of a two-component system, eukaryotic-like Ser/Thr protein kinase system and sigma factor system based on comparisons among M.tb H37Rv, M. bovis, and BCG, we have put a premium on this signaling circuit as the starting point for the generation of an attenuated TB vaccine.

  4. Priorities for CMV vaccine development.

    PubMed

    Krause, Philip R; Bialek, Stephanie R; Boppana, Suresh B; Griffiths, Paul D; Laughlin, Catherine A; Ljungman, Per; Mocarski, Edward S; Pass, Robert F; Read, Jennifer S; Schleiss, Mark R; Plotkin, Stanley A

    2013-12-17

    A multidisciplinary meeting addressed priorities related to development of vaccines against cytomegalovirus (CMV), the cause of congenital CMV (cCMV) disease and of serious disease in the immunocompromised. Participants discussed optimal uses of a CMV vaccine, aspects of clinical study design, and the value of additional research. A universal childhood CMV vaccine could potentially rapidly reduce cCMV disease, as infected children are sources of viral transmission to seronegative and seropositive mothers. A vaccine administered to adolescents or adult women could also reduce cCMV disease by making them immune prior to pregnancy. Clinical trials of CMV vaccines in women should evaluate protection against cCMV infection, an essential precursor of cCMV disease, which is a more practical and acceptable endpoint for assessing vaccine effects on maternal-fetal transmission. Clinical trials of vaccines to evaluate prevention of CMV disease in stem cell transplant recipients could use CMV viremia at a level triggering pre-emptive antiviral therapy as an endpoint, because widespread use of pre-emptive and prophylactic antivirals has rendered CMV-induced disease too rare to be a practical endpoint for clinical trials. In solid organ transplant patients, CMV-associated disease is sufficiently common for use as a primary endpoint. Additional research to advance CMV vaccine development should include identifying factors that predict fetal loss due to CMV, determining age-specific incidence and transmission rates, defining the mechanism and relative contributions of maternal reactivation and re-infection to cCMV disease, developing assays that can distinguish between reactivation and re-infection in seropositive vaccinees, further defining predictors of sequelae from cCMV infection, and identifying clinically relevant immune response parameters to CMV (including developing validated assays that could assess CMV antibody avidity) that could lead to the establishment of immune

  5. Priorities for CMV vaccine development

    PubMed Central

    Krause, Philip R.; Bialek, Stephanie R.; Boppana, Suresh B.; Griffiths, Paul D.; Laughlin, Catherine A.; Ljungman, Per; Mocarski, Edward S.; Pass, Robert F.; Read, Jennifer S.; Schleiss, Mark R.; Plotkin, Stanley A.

    2015-01-01

    A multidisciplinary meeting addressed priorities related to development of vaccines against cytomegalovirus (CMV), the cause of congenital CMV (cCMV) disease and of serious disease in the immunocompromised. Participants discussed optimal uses of a CMV vaccine, aspects of clinical study design, and the value of additional research. A universal childhood CMV vaccine could potentially rapidly reduce cCMV disease, as infected children are sources of viral transmission to seronegative and seropositive mothers. A vaccine administered to adolescents or adult women could also reduce cCMV disease by making them immune prior to pregnancy. Clinical trials of CMV vaccines in women should evaluate protection against cCMV infection, an essential precursor of cCMV disease, which is a more practical and acceptable endpoint for assessing vaccine effects on maternal-fetal transmission. Clinical trials of vaccines to evaluate prevention of CMV disease in stem cell transplant recipients could use CMV viremia at a level triggering preemptive antiviral therapy as an endpoint, because widespread use of preemptive and prophylactic antivirals has rendered CMV-induced disease too rare to be a practical endpoint for clinical trials. In solid organ transplant patients, CMV-associated disease is sufficiently common for use as a primary endpoint. Additional research to advance CMV vaccine development should include identifying factors that predict fetal loss due to CMV, determining age-specific incidence and transmission rates, defining the mechanism and relative contributions of maternal reactivation and re-infection to cCMV disease, developing assays that can distinguish between reactivation and re-infection in seropositive vaccinees, further defining predictors of sequelae from cCMV infection, and identifying clinically relevant immune response parameters to CMV (including developing validated assays that could assess CMV antibody avidity) that could lead to the establishment of immune

  6. Typhoid fever & vaccine development: a partially answered question.

    PubMed

    Marathe, Sandhya A; Lahiri, Amit; Negi, Vidya Devi; Chakravortty, Dipshikha

    2012-01-01

    Typhoid fever is a systemic disease caused by the human specific Gram-negative pathogen Salmonella enterica serovar Typhi (S. Typhi). The extra-intestinal infections caused by Salmonella are very fatal. The incidence of typhoid fever remains very high in impoverished areas and the emergence of multidrug resistance has made the situation worse. To combat and to reduce the morbidity and mortality caused by typhoid fever, many preventive measures and strategies have been employed, the most important being vaccination. In recent years, many Salmonella vaccines have been developed including live attenuated as well as DNA vaccines and their clinical trials have shown encouraging results. But with the increasing antibiotic resistance, the development of potent vaccine candidate for typhoid fever is a need of the hour. This review discusses the latest trends in the typhoid vaccine development and the clinical trials which are underway.

  7. Vaccines against enteric infections for the developing world

    PubMed Central

    Czerkinsky, Cecil; Holmgren, Jan

    2015-01-01

    Since the first licensure of the Sabin oral polio vaccine more than 50 years ago, only eight enteric vaccines have been licensed for four disease indications, and all are given orally. While mucosal vaccines offer programmatically attractive tools for facilitating vaccine deployment, their development remains hampered by several factors: —limited knowledge regarding the properties of the gut immune system during early life;—lack of mucosal adjuvants, limiting mucosal vaccine development to live-attenuated or killed whole virus and bacterial vaccines;—lack of correlates/surrogates of mucosal immune protection; and—limited knowledge of the factors contributing to oral vaccine underperformance in children from developing countries.There are now reasons to believe that the development of safe and effective mucosal adjuvants and of programmatically sound intervention strategies could enhance the efficacy of current and next-generation enteric vaccines, especially in lesser developed countries which are often co-endemic for enteric infections and malnutrition. These vaccines must be safe and affordable for the world's poorest, confer long-term protection and herd immunity, and must be able to contain epidemics. PMID:25964464

  8. Vaccines against enteric infections for the developing world.

    PubMed

    Czerkinsky, Cecil; Holmgren, Jan

    2015-06-19

    Since the first licensure of the Sabin oral polio vaccine more than 50 years ago, only eight enteric vaccines have been licensed for four disease indications, and all are given orally. While mucosal vaccines offer programmatically attractive tools for facilitating vaccine deployment, their development remains hampered by several factors: -limited knowledge regarding the properties of the gut immune system during early life; -lack of mucosal adjuvants, limiting mucosal vaccine development to live-attenuated or killed whole virus and bacterial vaccines; -lack of correlates/surrogates of mucosal immune protection; and -limited knowledge of the factors contributing to oral vaccine underperformance in children from developing countries. There are now reasons to believe that the development of safe and effective mucosal adjuvants and of programmatically sound intervention strategies could enhance the efficacy of current and next-generation enteric vaccines, especially in lesser developed countries which are often co-endemic for enteric infections and malnutrition. These vaccines must be safe and affordable for the world's poorest, confer long-term protection and herd immunity, and must be able to contain epidemics.

  9. Vaccination of full-sib channel catfish families against enteric septicemia of catfish with an oral live attenuated Edwardsiella ictaluri vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study evaluated the efficacy of an oral live-attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish in 20 full-sib fingerling channel catfish families. Each family was split into vaccinated and non-vaccinated groups. The vaccine was delivered orally by feeding fish diet...

  10. Safety and efficacy of a metabolic drift live attenuated Salmonella Gallinarum vaccine against fowl typhoid.

    PubMed

    Shehata, Awad Ali; Sultan, Hesham; Hafez, Hafez M; Krüger, Monika

    2013-03-01

    Fowl typhoid (FT), a systemic disease that results in septicemia in poultry, is caused by Salmonella enterica serovar Gallinarum biovar Gallinarum (SG). Mortality and morbidity rates from FT can reach up to 80%. Attenuated live Salmonella vaccine candidates have received considerable attention because they confer solid immunity, and they can produce systemic and mucosal immunity in the gut when administered orally. In the present study, five metabolic drift (MD) mutants with a single-(designated SG-Rif1, SG-Sm6) or double-attenuating marker (designated SG-Rif1-Sm4, SG-Sm6-Rif10, and SG-Rif1-Sm10) were isolated. The relative colony sizes to wild-type strain after 24 hr at 37 C incubation were 50%, 40%, 30%, 30%, and 20%, respectively. The probability of a back mutation can almost be excluded because the reduced colony sizes were stable after at least 50 passages on culture media. The safety and immunogenicity were evaluated in susceptible 1-day-old commercial layer chickens. After oral administration of 10(8) colony-forming units (CFU), all developed MD mutants proved to be safe and did not cause death of any infected birds during 15 days postvaccination, whereas chickens receiving 10(6) CFU SG wild-type strain showed a high mortality rate (40%). Vaccination of commercial layer chicks with SG-Rif1, SG-Sm6, SG-Rif1-Sm4, and SG-Sm6-Rif10 MD mutants could protect chickens against challenge by homologous wild-type strain; however, SG-Rif1-Sm10 could not protect against challenge, indicating hyperattenuation. In conclusion, vaccination with SG MD mutant vaccine appears to be safe and offers protection against FT in chickens.

  11. Development of an experimental tissue culture vaccine against Mediterranean theileriosis in Spain.

    PubMed

    Viseras, J; García-Fernández, P; Adroher, F J

    1998-02-01

    Vaccines against Mediterranean theileriosis have been developed in several countries where the disease is an economic problem. Tissue culture vaccines have been widely and successfully used to immunize cattle. Although Mediterranean theileriosis represents a constraint to dairy cattle production in Spain, no vaccines against this disease have been developed previously. The successful development of a tissue culture vaccine consisting of attenuated Theileria annulata schizont infected cells from an enzootic area of Spain and its efficacy under experimental conditions is reported. Vaccinated calves were resistant to homologous challenge showing no signs of theileriosis while non-vaccinated calves showed typical signs of disease.

  12. Infection-enhancing lipopeptides do not improve intranasal immunization of cotton rats with a delta-G candidate live-attenuated human respiratory syncytial virus vaccine.

    PubMed

    Tien Nguyen, D; Boes, Jolande; van Amerongen, Geert; van Remmerden, Yvonne; Yüksel, Selma; Guichelaar, Teun; Osterhaus, Albert D M E; de Swart, Rik L

    2013-12-01

    Development of live-attenuated human respiratory syncytial virus (HRSV) vaccines has proven to be difficult. Several vaccine candidates were found to be over-attenuated and displayed limited immunogenicity. Recently, we identified three synthetic cationic lipopeptides that enhanced paramyxovirus infections in vitro. The infection enhancement proved to be mediated by enhanced virus binding to target cells. We hypothesized that these lipopeptides can be used as adjuvants to promote immune responses induced by live-attenuated paramyxovirus vaccines. This hypothesis was tested in a vaccination and challenge model in cotton rats, using a previously described recombinant live-attenuated candidate HRSV vaccine lacking the gene encoding the G glycoprotein (rHRSVΔG). Surprisingly, intranasal vaccination of cotton rats with rHRSVΔG formulated in infection-enhancing lipopeptides resulted in reduced virus loads in nasopharyngeal lavages, reduced seroconversion levels and reduced protection from wild-type HRSV challenge. In conclusion, we were unable to demonstrate the feasibility of lipopeptides as adjuvants for a candidate live-attenuated HRSV vaccine in the cotton rat model.

  13. Long-term safety assessment of live attenuated tetravalent dengue vaccines: deliberations from a WHO technical consultation.

    PubMed

    Bentsi-Enchill, Adwoa D; Schmitz, Julia; Edelman, Robert; Durbin, Anna; Roehrig, John T; Smith, Peter G; Hombach, Joachim; Farrar, Jeremy

    2013-05-28

    Dengue is a rapidly growing public health threat with approximately 2.5 billion people estimated to be at risk. Several vaccine candidates are at various stages of pre-clinical and clinical development. Thus far, live dengue vaccine candidates have been administered to several thousands of volunteers and were well-tolerated, with minimal short-term safety effects reported in Phase I and Phase II clinical trials. Based on the natural history of dengue, a theoretical possibility of an increased risk of severe dengue as a consequence of vaccination has been hypothesized but not yet observed. In October 2011, the World Health Organization (WHO) convened a consultation of experts in dengue, vaccine regulation and vaccine safety to review the current scientific evidence regarding safety concerns associated with live attenuated dengue vaccines and, in particular, to consider methodological approaches for their long-term evaluation. In this paper we summarize the scientific background and methodological considerations relevant to the safety assessment of these vaccines. Careful planning and a coordinated approach to safety assessment are recommended to ensure adequate long-term evaluation of dengue vaccines that will support their introduction and continued use.

  14. Chinese vaccine products go global: vaccine development and quality control.

    PubMed

    Xu, Miao; Liang, Zhenglun; Xu, Yinghua; Wang, Junzhi

    2015-05-01

    Through the continuous efforts of several generations, China has become one of the few countries in the world that is capable of independently addressing all the requirements by the Expanded Program on Immunization. Regulatory science is applied to continuously improve the vaccine regulatory system. Passing the prequalification by WHO has allowed Chinese vaccine products to go global. Chinese vaccine products not only secure disease prevention and control domestically but also serve the needs for international public health. This article describes the history of Chinese vaccine development, the current situation of Chinese vaccine industry and its contribution to the prevention and control of infectious diseases. We also share our experience of national quality control and vaccine regulation during the past decades. China's experience in vaccine development and quality control can benefit other countries and regions worldwide, including the developing countries.

  15. Genomic variations associated with attenuation in Mycobacterium avium subsp. paratuberculosis vaccine strains

    PubMed Central

    2013-01-01

    Background Mycobacterium avium subspecies paratuberculosis (MAP) whole cell vaccines have been widely used tools in the control of Johne’s disease in animals despite being unable to provide complete protection. Current vaccine strains derive from stocks created many decades ago; however their genotypes, underlying mechanisms and relative degree of their attenuation are largely unknown. Results Using mouse virulence studies we confirm that MAP vaccine strains 316 F, II and 2e have diverse but clearly attenuated survival and persistence characteristics compared with wild type strains. Using a pan genomic microarray we characterise the genomic variations in a panel of vaccine strains sourced from stocks spanning over 40 years of maintenance. We describe multiple genomic variations specific for individual vaccine stocks in both deletion (26–32 Kbp) and tandem duplicated (11–40 Kbp) large variable genomic islands and insertion sequence copy numbers. We show individual differences suitable for diagnostic differentiation between vaccine and wild type genotypes and provide evidence for functionality of some of the deleted MAP-specific genes and their possible relation to attenuation. Conclusions This study shows how culture environments have influenced MAP genome diversity resulting in large tandem genomic duplications, deletions and transposable element activity. In combination with classical selective systematic subculture this has led to fixation of specific MAP genomic alterations in some vaccine strain lineages which link the resulting attenuated phenotypes with deficiencies in high reactive oxygen species handling. PMID:23339684

  16. In silico identification of genetically attenuated vaccine candidate genes for Plasmodium liver stage.

    PubMed

    Kumar, Hirdesh; Frischknecht, Friedrich; Mair, Gunnar R; Gomes, James

    2015-12-01

    Genetically attenuated parasites (GAPs) that lack genes essential for the liver stage of the malaria parasite, and therefore cause developmental arrest, have been developed as live vaccines in rodent malaria models and recently been tested in humans. The genes targeted for deletion were often identified by trial and error. Here we present a systematic gene - protein and transcript - expression analyses of several Plasmodium species with the aim to identify candidate genes for the generation of novel GAPs. With a lack of liver stage expression data for human malaria parasites, we used data available for liver stage development of Plasmodium yoelii, a rodent malaria model, to identify proteins expressed in the liver stage but absent from blood stage parasites. An orthology-based search was then employed to identify orthologous proteins in the human malaria parasite Plasmodium falciparum resulting in a total of 310 genes expressed in the liver stage but lacking evidence of protein expression in blood stage parasites. Among these 310 possible GAP candidates, we further studied Plasmodium liver stage proteins by phyletic distribution and functional domain analyses and shortlisted twenty GAP-candidates; these are: fabB/F, fabI, arp, 3 genes encoding subunits of the PDH complex, dnaJ, urm1, rS5, ancp, mcp, arh, gk, lisp2, valS, palm, and four conserved Plasmodium proteins of unknown function. Parasites lacking one or several of these genes might yield new attenuated malaria parasites for experimental vaccination studies.

  17. Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs.

    PubMed

    Muñoz-González, Sara; Perez-Simó, Marta; Muñoz, Marta; Bohorquez, José Alejandro; Rosell, Rosa; Summerfield, Artur; Domingo, Mariano; Ruggli, Nicolas; Ganges, Llilianne

    2015-07-09

    Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.

  18. Titration of individual strains in trivalent live-attenuated influenza vaccine without neutralization.

    PubMed

    Sirinonthanawech, Naraporn; Surichan, Somchaiya; Namsai, Aphinya; Puthavathana, Pilaipan; Auewarakul, Prasert; Kongchanagul, Alita

    2016-11-01

    Formulation and quality control of trivalent live-attenuated influenza vaccine requires titration of infectivity of individual strains in the trivalent mix. This is usually performed by selective neutralization of two of the three strains and titration of the un-neutralized strain in cell culture or embryonated eggs. This procedure requires standard sera with high neutralizing titer against each of the three strains. Obtaining standard sera, which can specifically neutralize only the corresponding strain of influenza viruses and is able to completely neutralize high concentration of virus in the vaccine samples, can be a problem for many vaccine manufacturers as vaccine stocks usually have very high viral titers and complete neutralization may not be obtained. Here an alternative approach for titration of individual strain in trivalent vaccine without the selective neutralization is presented. This was done by detecting individual strains with specific antibodies in an end-point titration of a trivalent vaccine in cell culture. Similar titers were observed in monovalent and trivalent vaccines for influenza A H3N2 and influenza B strains, whereas the influenza A H1N1 strain did not grow well in cell culture. Viral interference among the vaccine strains was not observed. Therefore, providing that vaccine strains grow well in cell culture, this assay can reliably determine the potency of individual strains in trivalent live-attenuated influenza vaccines.

  19. Reverse Genetics Approaches for the Development of Influenza Vaccines

    PubMed Central

    Nogales, Aitor; Martínez-Sobrido, Luis

    2016-01-01

    Influenza viruses cause annual seasonal epidemics and occasional pandemics of human respiratory disease. Influenza virus infections represent a serious public health and economic problem, which are most effectively prevented through vaccination. However, influenza viruses undergo continual antigenic variation, which requires either the annual reformulation of seasonal influenza vaccines or the rapid generation of vaccines against potential pandemic virus strains. The segmented nature of influenza virus allows for the reassortment between two or more viruses within a co-infected cell, and this characteristic has also been harnessed in the laboratory to generate reassortant viruses for their use as either inactivated or live-attenuated influenza vaccines. With the implementation of plasmid-based reverse genetics techniques, it is now possible to engineer recombinant influenza viruses entirely from full-length complementary DNA copies of the viral genome by transfection of susceptible cells. These reverse genetics systems have provided investigators with novel and powerful approaches to answer important questions about the biology of influenza viruses, including the function of viral proteins, their interaction with cellular host factors and the mechanisms of influenza virus transmission and pathogenesis. In addition, reverse genetics techniques have allowed the generation of recombinant influenza viruses, providing a powerful technology to develop both inactivated and live-attenuated influenza vaccines. In this review, we will summarize the current knowledge of state-of-the-art, plasmid-based, influenza reverse genetics approaches and their implementation to provide rapid, convenient, safe and more effective influenza inactivated or live-attenuated vaccines. PMID:28025504

  20. Single-dose live-attenuated Nipah virus vaccines confer complete protection by eliciting antibodies directed against surface glycoproteins

    PubMed Central

    DeBuysscher, Blair L.; Scott, Dana; Marzi, Andrea; Prescott, Joseph; Feldmann, Heinz

    2016-01-01

    Background Nipah virus (NiV), a zoonotic pathogen causing severe respiratory illness and encephalitis in humans, emerged in Malaysia in 1998 with subsequent outbreaks on an almost annual basis since 2001 in parts of the Indian subcontinent. The high case fatality rate, human-to-human transmission, wide-ranging reservoir distribution and lack of licensed intervention options are making NiV a serious regional and potential global public health problem. The objective of this study was to develop a fast-acting, single-dose NiV vaccine that could be implemented in a ring vaccination approach during outbreaks. Methods In this study we have designed new live-attenuated vaccine vectors based on recombinant vesicular stomatitis viruses (rVSV) expressing NiV glycoproteins (G or F) or nucleoprotein (N) and evaluated their protective efficacy in Syrian hamsters, an established NiV animal disease model. We further characterized the humoral immune response to vaccination in hamsters using ELISA and neutralization assays and performed serum transfer studies. Results Vaccination of Syrian hamsters with a single dose of the rVSV vaccine vectors resulted in strong humoral immune responses with neutralizing activities found only in those animals vaccinated with rVSV expressing NiV G or F proteins. Vaccinated animals with neutralizing antibody responses were completely protected from lethal NiV disease, whereas animals vaccinated with rVSV expressing NiV N showed only partial protection. Protection of NiV G or F vaccinated animals was conferred by antibodies, most likely the neutralizing fraction, as demonstrated by serum transfer studies. Protection of N-vaccinated hamsters was not antibody-dependent indicating a role of adaptive cellular responses for protection. Conclusions The rVSV vectors expressing Nipah virus G or F are prime candidates for new ‘emergency vaccines’ to be utilized for NiV outbreak management. PMID:24631094

  1. Characterization of immune responses induced by inactivated, live attenuated and DNA vaccines against Japanese encephalitis virus in mice.

    PubMed

    Li, Jieqiong; Chen, Hui; Wu, Na; Fan, Dongying; Liang, Guodong; Gao, Na; An, Jing

    2013-08-28

    Vaccination is the most effective countermeasure for protecting individuals from Japanese encephalitis virus (JEV) infection. There are two types of JEV vaccines currently used in China: the Vero cell-derived inactivated vaccine and the live attenuated vaccine. In this study, we characterized the immune response and protective efficacy induced in mice by the inactivated vaccine, live attenuated vaccine and the DNA vaccine candidate pCAG-JME, which expresses JEV prM-E proteins. We found that the live attenuated vaccine conferred 100% protection and resulted in the generation of high levels of specific anti-JEV antibodies and cytokines. The pCAG-JME vaccine induced protective immunity as well as the live attenuated vaccine. Unexpectedly, immunization with the inactivated vaccine only induced a limited immune response and partial protection, which may be due to the decreased activity of dendritic cells and the expansion of CD4+CD25+Foxp3+ regulatory T cells observed in these mice. Altogether, our results suggest that the live attenuated vaccine is more effective in providing protection against JEV infection than the inactivated vaccine and that pCAG-JME will be a potential JEV vaccine candidate.

  2. DENGUE VACCINES.

    PubMed

    Thisyakorn, Usa; Thisyakorn, Chule

    2015-01-01

    The uniqueness of the dengue viruses (DENVs) and the spectrum of disease resulting from infection have made dengue vaccine development difficult. Several vaccine candidates are currently being evaluated in clinical studies. The candidate currently at the most advanced clinical development stage, a live-attenuated tetravalent vaccine based on the chimeric yellow fever-dengue virus (CYD-TDV), has progressed to Phase 3 efficacy studies. Several other live-attenuated vaccines, as well as subunit, DNA, and purified inactivated vaccine candidates are at earlier stages of clinical development. Additional technological approaches, such as virus-vectored and Virus-Like Particles (VLP)-based vaccines are under evaluation in preclinical studies.

  3. Experimental study of a further attenuated live measles vaccine of the Sugiyama strain in Iran

    PubMed Central

    Mirchamsy, H.; Shafyi, A.; Rafyi, M. R.; Bahrami, S.; Nazari, P.; Fatemie, S.

    1974-01-01

    After encouraging results of the mass vaccination programme in Iran, in which 5 million children in rural areas were vaccinated with the Japanese Sugiyama strain at its 82nd passage in baby calf kidney, and a progressive decrease in the incidence of measles as well as a reduction of excessive infant mortality, a further attenuated vaccine, produced with the same strain, cloned in Japan, was compared in a field trial with the parent vaccine. The new strain caused fewer reactions than the original strain. Seroconversion with a geometric mean antibody titre of 6·1 was observed in 95% of susceptible children. PMID:4522721

  4. Generation and protective efficacy of a cold-adapted attenuated avian H9N2 influenza vaccine

    PubMed Central

    Wei, Yandi; Qi, Lu; Gao, Huijie; Sun, Honglei; Pu, Juan; Sun, Yipeng; Liu, Jinhua

    2016-01-01

    To prevent H9N2 avian influenza virus infection in chickens, a long-term vaccination program using inactivated vaccines has been implemented in China. However, the protective efficacy of inactivated vaccines against antigenic drift variants is limited, and H9N2 influenza virus continues to circulate in vaccinated chicken flocks in China. Therefore, developing a cross-reactive vaccine to control the impact of H9N2 influenza in the poultry industry remains a high priority. In the present study, we developed a live cold-adapted H9N2 influenza vaccine candidate (SD/01/10-ca) by serial passages in embryonated eggs at successively lower temperatures. A total of 13 amino acid mutations occurred during the cold-adaptation of this H9N2 virus. The candidate was safe in chickens and induced robust hemagglutination-inhibition antibody responses and influenza virus–specific CD4+ and CD8+ T cell immune responses in chickens immunized intranasally. Importantly, the candidate could confer protection of chickens from homologous and heterogenous H9N2 viruses. These results demonstrated that the cold-adapted attenuated H9N2 virus would be selected as a vaccine to control the infection of prevalent H9N2 influenza viruses in chickens. PMID:27457755

  5. Vaccine Development Against Leishmania donovani

    PubMed Central

    Das, Amrita; Ali, Nahid

    2012-01-01

    Visceral leishmaniasis (VL) caused by Leishmania donovani and Leishmania infantum/chagasi represents the second most challenging infectious disease worldwide, leading to nearly 500,000 new cases and 60,000 deaths annually. Zoonotic VL caused by L. infantum is a re-emergent canid zoonoses which represents a complex epidemiological cycle in the New world where domestic dogs serve as a reservoir host responsible for potentially fatal human infection and where dog culling is the only measure for reservoir control. Life-long immunity to VL has motivated development of prophylactic vaccines against the disease but very few have progressed beyond the experimental stage. No licensed vaccine is available till date against any form of leishmaniasis. High toxicity and increasing resistance to the current chemotherapeutic regimens have further complicated the situation in VL endemic regions of the world. Advances in vaccinology, including recombinant proteins, novel antigen-delivery systems/adjuvants, heterologous prime-boost regimens and strategies for intracellular antigen presentation, have contributed to recent advances in vaccine development against VL. Attempts to develop an effective vaccine for use in domestic dogs in areas of canine VL should be pursued for preventing human infection. Studies in animal models and human patients have revealed the pathogenic mechanisms of disease progression and features of protective immunity. This review will summarize the accumulated knowledge of pathogenesis, immune response, and prerequisites for protective immunity against human VL. Authors will discuss promising vaccine candidates, their developmental status and future prospects in a quest for rational vaccine development against the disease. In addition, several challenges such as safety issues, renewed and coordinated commitment to basic research, preclinical studies and trial design will be addressed to overcome the problems faced in developing prophylactic strategies for

  6. A Live Attenuated Vaccine for Lassa Fever Made by Reassortment of Lassa and Mopeia Viruses

    PubMed Central

    Lukashevich, Igor S.; Patterson, Jean; Carrion, Ricardo; Moshkoff, Dmitry; Ticer, Anysha; Zapata, Juan; Brasky, Kathleen; Geiger, Robert; Hubbard, Gene B.; Bryant, Joseph; Salvato, Maria S.

    2005-01-01

    Lassa virus (LASV) and Mopeia virus (MOPV) are closely related Old World arenaviruses that can exchange genomic segments (reassort) during coinfection. Clone ML29, selected from a library of MOPV/LASV (MOP/LAS) reassortants, encodes the major antigens (nucleocapsid and glycoprotein) of LASV and the RNA polymerase and zinc-binding protein of MOPV. Replication of ML29 was attenuated in guinea pigs and nonhuman primates. In murine adoptive-transfer experiments, as little as 150 PFU of ML29 induced protective cell-mediated immunity. All strain 13 guinea pigs vaccinated with clone ML29 survived at least 70 days after LASV challenge without either disease signs or histological lesions. Rhesus macaques inoculated with clone ML29 developed primary virus-specific T cells capable of secreting gamma interferon in response to homologous MOP/LAS and heterologous MOPV and lymphocytic choriomeningitis virus. Detailed examination of two rhesus macaques infected with this MOPV/LAS reassortant revealed no histological lesions or disease signs. Thus, ML29 is a promising attenuated vaccine candidate for Lassa fever. PMID:16254329

  7. Communicating vaccine safety during the development and introduction of vaccines.

    PubMed

    Kochhar, Sonali

    2015-01-01

    Vaccines are the best defense available against infectious diseases. Vaccine safety is of major focus for regulatory bodies, vaccine manufacturers, public health authorities, health care providers and the public as vaccines are often given to healthy children and adults as well as to pregnant woman. Safety assessment is critical at all stages of vaccine development. Effective, clear and consistent communication of the risks and benefits of vaccines and advocacy during all stages of clinical research (including the preparation, approvals, conduct of clinical trials through the post marketing phase) is critically important. This needs to be done for all major stakeholders (e.g. community members, Study Team, Health Care Providers, Ministry of Health, Regulators, Ethics Committee members, Public Health Authorities and Policy Makers). Improved stakeholder alignment would help to address some of the concerns that may affect the clinical research, licensing of vaccines and their wide-spread use in immunization programs around the world.

  8. Generation and Characterization of Live Attenuated Influenza A(H7N9) Candidate Vaccine Virus Based on Russian Donor of Attenuation

    PubMed Central

    Shcherbik, Svetlana; Pearce, Nicholas; Balish, Amanda; Jones, Joyce; Thor, Sharmi; Davis, Charles Todd; Pearce, Melissa; Tumpey, Terrence; Cureton, David; Chen, Li-Mei; Villanueva, Julie; Bousse, Tatiana L.

    2015-01-01

    Background Avian influenza A (H7N9) virus has emerged recently and continues to cause severe disease with a high mortality rate in humans prompting the development of candidate vaccine viruses. Live attenuated influenza vaccines (LAIV) are 6:2 reassortant viruses containing the HA and NA gene segments from wild type influenza viruses to induce protective immune responses and the six internal genes from Master Donor Viruses (MDV) to provide temperature sensitive, cold-adapted and attenuated phenotypes. Methodology/Principal Findings LAIV candidate A/Anhui/1/2013(H7N9)-CDC-LV7A (abbreviated as CDC-LV7A), based on the Russian MDV, A/Leningrad/134/17/57 (H2N2), was generated by classical reassortment in eggs and retained MDV temperature-sensitive and cold-adapted phenotypes. CDC-LV7A had two amino acid substitutions N123D and N149D (H7 numbering) in HA and one substitution T10I in NA. To evaluate the role of these mutations on the replication capacity of the reassortants in eggs, the recombinant viruses A(H7N9)RG-LV1 and A(H7N9)RG-LV2 were generated by reverse genetics. These changes did not alter virus antigenicity as ferret antiserum to CDC-LV7A vaccine candidate inhibited hemagglutination by homologous A(H7N9) virus efficiently. Safety studies in ferrets confirmed that CDC-LV7A was attenuated compared to wild-type A/Anhui/1/2013. In addition, the genetic stability of this vaccine candidate was examined in eggs and ferrets by monitoring sequence changes acquired during virus replication in the two host models. No changes in the viral genome were detected after five passages in eggs. However, after ten passages additional mutations were detected in the HA gene. The vaccine candidate was shown to be stable in the ferret model; post-vaccination sequence data analysis showed no changes in viruses collected in nasal washes present at day 5 or day 7. Conclusions/Significance Our data indicate that the A/Anhui/1/2013(H7N9)-CDC-LV7A reassortant virus is a safe and

  9. Efficacy of a new attenuated duck parvovirosis vaccine in Muscovy ducks.

    PubMed

    Maurin-Bernaud, L; Goutebroze, S; Merdy, O; Chanay, A; Cozette, V; Le Gros, F-X

    2014-09-20

    The efficacy of a new live attenuated parvovirosis vaccine was tested in conventional ducklings against Derzsy's disease by comparing two vaccination regimens. Ducklings were vaccinated with either one injection at 17 days of age or two injections at 1 and 17 days of age. Controls and vaccinated ducklings were challenged with a virulent Derzsy strain at 21 days of age (day 20). Weight was measured on days 20, 34 and 42/43. Surviving birds were necropsied on day 42/43. Protection rates were significantly higher in the groups vaccinated once (90 per cent, P=0.003) and twice (95 per cent, P<0.001) than in the control group (59 per cent). The bodyweight was significantly higher in both vaccinated groups than in the control group on day 34 (P=0.008 and P<0.001, respectively) and day 42/43 (P<0.001 for both groups). The growth was significantly higher in the group vaccinated twice than the group vaccinated once on day 34 (P=0.047) and day 42/43 (P=0.017). Both vaccination regimens provided a quick onset of immunity. The higher weight gain in the group vaccinated twice suggests that an early vaccination at hatchery followed by a second injection at 17 days of age is an optimal and practical schedule to prevent parvovirosis.

  10. Serological response of foals to polyvalent and monovalent live-attenuated African horse sickness virus vaccines.

    PubMed

    Crafford, J E; Lourens, C W; Smit, T K; Gardner, I A; MacLachlan, N J; Guthrie, A J

    2014-06-17

    African horse sickness (AHS) is typically a highly fatal disease in susceptible horses and vaccination is currently used to prevent the occurrence of disease in endemic areas. Similarly, vaccination has been central to the control of incursions of African horse sickness virus (AHSV) into previously unaffected areas and will likely play a significant role in any future incursions. Horses in the AHSV-infected area in South Africa are vaccinated annually with a live-attenuated (modified-live virus [MLV]) vaccine, which includes a cocktail of serotypes 1, 3, 4 (bottle 1) and 2, 6-8 (bottle 2) delivered in two separate doses at least 21 days apart. In this study, the neutralising antibody response of foals immunized with this polyvalent MLV AHSV vaccine was evaluated and compared to the response elicited to monovalent MLV AHSV serotypes. Naïve foals were immunized with either the polyvalent MLV AHSV vaccine, or a combination of monovalent MLV vaccines containing individual AHSV serotypes 1, 4, 7 or 8. There was a marked and consistent difference in the immunogenicity of individual virus serotypes contained in the MLV vaccines. Specifically, foals most consistently seroconverted to AHSV-1 and responses to other serotypes were highly variable, and often weak or not detected. The serotype-specific responses of foals given the monovalent MLV vaccines were similar to those of foals given the polyvalent MLV preparation suggesting that there is no obvious enhanced immune response through the administration of a monovalent vaccine as opposed to the polyvalent vaccine.

  11. Attenuated strains of Mycobacterium avium subspecies paratuberculosis as vaccine candidates against Johne's disease.

    PubMed

    Settles, Erik W; Kink, John A; Talaat, Adel

    2014-04-11

    Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is the causative agent of Johne's disease in ruminants. Johne's disease has a severe economic impact on the dairy industry in the USA and worldwide. In an effort to combat this disease, we screened several transposon mutants that were attenuated in the murine model of paratuberculosis for the potential use as live attenuated vaccines. Using the murine model, two vaccine candidates (pgs1360, pgs3965 with mutations of fabG2_2 and umaA1, respectively) were at or below the limit of detection for tissue colonization suggesting their low level persistence and hence safety. Prior to challenge, both candidates induced a M. paratuberculosis-specific IFN-γ, an indication of eliciting cell-mediated immunity. Following challenge with a virulent strain of M. paratuberculosis, the two vaccine candidates significantly reduced bacterial colonization in organs with reduced histological scores compared to control animals. In addition, one of the vaccine candidates (pgs3965) also induced IL-17a, a cytokine associated with protective immunity in mycobacterial infection. Our analysis suggested that the pgs3965 vaccine candidate is a potential live-attenuated vaccine that could be tested further in ruminant models of paratuberculosis. The analysis also validated our screening strategy to identify effective vaccine candidates against intracellular pathogens.

  12. Temperature-Sensitive Live-Attenuated Canine Influenza Virus H3N8 Vaccine.

    PubMed

    Nogales, Aitor; Rodriguez, Laura; Chauché, Caroline; Huang, Kai; Reilly, Emma C; Topham, David J; Murcia, Pablo R; Parrish, Colin R; Martínez-Sobrido, Luis

    2017-02-15

    Canine influenza is a respiratory disease of dogs caused by canine influenza virus (CIV). CIV subtypes responsible for influenza in dogs include H3N8, which originated from the transfer of H3N8 equine influenza virus to dogs; and the H3N2 CIV, which is an avian-origin virus that adapted to infect dogs. Influenza infections are most effectively prevented through vaccination to reduce transmission and future infection. Currently, only inactivated influenza vaccines (IIVs) are available for the prevention of CIV in dogs. However, the efficacy of IIVs is suboptimal, and novel approaches are necessary for the prevention of disease caused by this canine respiratory pathogen. Using reverse genetics techniques, we have developed a live-attenuated CIV vaccine (LACIV) for the prevention of H3N8 CIV. The H3N8 LACIV replicates efficiently in canine cells at 33°C but is impaired at temperatures of 37 to 39°C and was attenuated compared to wild-type H3N8 CIV in vivo and ex vivo The LACIV was able to induce protection against H3N8 CIV challenge with a single intranasal inoculation in mice. Immunogenicity and protection efficacy were better than that observed with a commercial CIV H3N8 IIV but provided limited cross-reactive immunity and heterologous protection against H3N2 CIV. These results demonstrate the feasibility of implementing a LAIV approach for the prevention and control of H3N8 CIV in dogs and suggest the need for a new LAIV for the control of H3N2 CIV.

  13. The development of global vaccine stockpiles

    PubMed Central

    Yen, Catherine; Hyde, Terri B; Costa, Alejandro J; Fernandez, Katya; Tam, John S; Hugonnet, Stéphane; Huvos, Anne M; Duclos, Philippe; Dietz, Vance J; Burkholder, Brenton T

    2016-01-01

    Global vaccine stockpiles, in which vaccines are reserved for use when needed for emergencies or supply shortages, have effectively provided countries with the capacity for rapid response to emergency situations, such as outbreaks of yellow fever and meningococcal meningitis. The high cost and insufficient supply of many vaccines, including oral cholera vaccine and pandemic influenza vaccine, have prompted discussion on expansion of the use of vaccine stockpiles to address a wider range of emerging and re-emerging diseases. However, the decision to establish and maintain a vaccine stockpile is complex and must take account of disease and vaccine characteristics, stockpile management, funding, and ethical concerns, such as equity. Past experience with global vaccine stockpiles provide valuable information about the processes for their establishment and maintenance. In this Review we explored existing literature and stockpile data to discuss the lessons learned and to inform the development of future vaccine stockpiles. PMID:25661473

  14. Current efforts and future prospects in the development of live mycobacteria as vaccines.

    PubMed

    Ng, Tony W; Saavedra-Ávila, Noemí A; Kennedy, Steven C; Carreño, Leandro J; Porcelli, Steven A

    2015-01-01

    The development of more effective vaccines against Mycobacterium tuberculosis (Mtb) remains a major goal in the effort to reduce the enormous global burden of disease caused by this pathogen. Whole-cell vaccines based on live mycobacteria with attenuated virulence represent an appealing approach, providing broad antigen exposure and intrinsic adjuvant properties to prime durable immune responses. However, designing vaccine strains with an optimal balance between attenuation and immunogenicity has proven to be extremely challenging. Recent basic and clinical research efforts have broadened our understanding of Mtb pathogenesis and created numerous new vaccine candidates that have been designed to overcome different aspects of immune evasion by Mtb. In this review, we provide an overview of the current efforts to create improved vaccines against tuberculosis based on modifications of live attenuated mycobacteria. In addition, we discuss the use of such vaccine strains as vectors for stimulating protective immunity against other infectious diseases and cancers.

  15. Generation of a live rabies vaccine strain attenuated by multiple mutations and evaluation of its safety and efficacy.

    PubMed

    Nakagawa, Keisuke; Ito, Naoto; Masatani, Tatsunori; Abe, Masako; Yamaoka, Satoko; Ito, Yuki; Okadera, Kota; Sugiyama, Makoto

    2012-05-21

    An amino acid substitution at position 333 in rabies virus G protein is known to determine the pathogenicity: strains with Arg or Lys at that position kill adult mice after intracerebral inoculation, whereas strains with other amino acids cause non-lethal infection. Based on those findings, attenuated rabies virus strains have been established and used for oral vaccines mainly for wild animals. However, considering the possibility of back-mutation to the virulent phenotype, a strain that is attenuated by multiple mutations not only in the G protein but also in other viral proteins would be more appropriate as a safe live vaccine. We previously demonstrated that the fixed rabies virus Ni-CE strain, which causes only transient body weight loss in adult mice after intracerebral inoculation, is mainly attenuated by mutations in the N, P and M proteins, while this strain has virulent-type Arg at position 333 in the G protein. In this study, to obtain a live vaccine strain that is attenuated by multiple mutations, we generated Ni-CE mutant, Ni-CE(G333Glu) strain, which has an Arg-to-Glu mutation at position 333 in the G protein, and examined its pathogenicity and immunogenicity. We found that, in contrast to Ni-CE strain, Ni-CE(G333Glu) strain did not cause transient body weight loss in adult mice after intracerebral inoculation. The attenuated phenotype of Ni-CE(G333Glu) strain did not change even after 10 serial intracerebral passages in suckling mice. We also demonstrated that inoculation of Ni-CE(G333Glu) strain induced virus-neutralizing antibody in immunized mice and protected the mice from lethal challenge. These results indicate that Ni-CE(G333Glu) strain is a promising candidate for development of a live rabies vaccine with a high safety level.

  16. Alternative live-attenuated influenza vaccines based on modifications in the polymerase genes protect against epidemic and pandemic flu.

    PubMed

    Solórzano, Alicia; Ye, Jianqiang; Pérez, Daniel R

    2010-05-01

    Human influenza is a seasonal disease associated with significant morbidity and mortality. Influenza vaccination is the most effective means for disease prevention. We have previously shown that mutations in the PB1 and PB2 genes of the live-attenuated influenza vaccine (LAIV) from the cold-adapted (ca) influenza virus A/Ann Arbor/6/60 (H2N2) could be transferred to avian influenza viruses and produce partially attenuated viruses. We also demonstrated that avian influenza viruses carrying the PB1 and PB2 mutations could be further attenuated by stably introducing a hemagglutinin (HA) epitope tag in the PB1 gene. In this work, we wanted to determine whether these modifications would also result in attenuation of a so-called triple reassortant (TR) swine influenza virus (SIV). Thus, the TR influenza A/swine/Wisconsin/14094/99 (H3N2) virus was generated by reverse genetics and subsequently mutated in the PB1 and PB2 genes. Here we show that a combination of mutations in this TR backbone results in an attenuated virus in vitro and in vivo. Furthermore, we show the potential of our TR backbone as a vaccine that provides protection against the 2009 swine-origin pandemic influenza H1N1 virus (S-OIV) when carrying the surface of a classical swine strain. We propose that the availability of alternative backbones to the conventional ca A/Ann Arbor/6/60 LAIV strain could also be useful in epidemic and pandemic influenza and should be considered for influenza vaccine development. In addition, our data provide evidence that the use of these alternative backbones could potentially circumvent the effects of original antigenic sin (OAS) in certain circumstances.

  17. A Live Attenuated H7N3 Influenza Virus Vaccine is Well-tolerated and Immunogenic in a Phase I Trial in Healthy Adults

    PubMed Central

    Talaat, Kawsar R.; Karron, Ruth A.; Callahan, Karen A.; Luke, Catherine J.; DiLorenzo, Susan C.; Chen, Grace L.; Lamirande, Elaine W.; Jin, Hong; Coelingh, Kathy L.; Murphy, Brian R.; Kemble, George; Subbarao, Kanta

    2009-01-01

    Background Live attenuated influenza vaccines (LAIV) are being developed and tested against a variety of influenza viruses with pandemic potential. We describe the results of an open label Phase I trial of a live attenuated H7N3 virus vaccine. Methods and Findings The H7N3 BC 2004/AA ca virus is a live attenuated, cold-adapted, temperature-sensitive influenza virus derived by reverse genetics from the wild-type low pathogenicity avian influenza virus A/chicken/British Columbia/CN-6/2004 (H7N3) and the A/AA/6/60 ca (H2N2) virus that is the Master Donor Virus of the live, intranasal seasonal influenza vaccine. We evaluated the safety, infectivity, and immunogenicity of two doses of 107.5 TCID50 of the vaccine administered by nasal spray 5 weeks apart to normal healthy seronegative adult volunteers in an inpatient isolation unit. The subjects were followed for 2 months after 1 dose of vaccine or for 4 weeks after the second dose. Twenty-one subjects received the first dose of the vaccine, and 17 subjects received two doses. The vaccine was generally well tolerated. No serious adverse events occurred during the trial. The vaccine was highly restricted in replication: 6 (29%) subjects had virus recoverable by culture or by rRT-PCR after the first dose. Replication of vaccine virus was not detected following the second dose. Despite the restricted replication of the vaccine, 90% of the subjects developed an antibody response as measured by any assay: 62% by hemagglutination inhibition assay, 48% by microneutralization assay, 48% by ELISA for H7 HA-specific serum IgG or 71% by ELISA for H7 HA-specific serum IgA, after either one or two doses. Following the first dose, vaccine-specific IgG secreting cells as measured by ELISPOT increased from a mean of 0.1 to 41.6/106 PBMCs; vaccine specific IgA secreting cells increased from 2 to 16.4/106 PBMCs. The antibody secreting cell response after the second dose was less vigorous, which is consistent with the observed low

  18. Comparison of the Effectiveness of Trivalent Inactivated Influenza Vaccine and Live, Attenuated Influenza Vaccine in Preventing Influenza-Like Illness among US Service Members, 2006-2009

    DTIC Science & Technology

    2012-11-26

    controlled studies. Vaccine 2012; 30:886–92. 11. Piedra PA, Gaglani MJ, Kozinetz CA, et al. Trivalent live attenuated intranasal influenza vaccine...120:e553–64. 12. Halloran ME, Piedra PA, Longini IM Jr, et al. Efficacy of trivalent, cold-adapted, influenza virus vaccine against influenza A (Fujian

  19. Selected prfA* mutations in recombinant attenuated Listeria monocytogenes strains augment expression of foreign immunogens and enhance vaccine-elicited humoral and cellular immune responses.

    PubMed

    Yan, Lin; Qiu, Jin; Chen, Jianbo; Ryan-Payseur, Bridgett; Huang, Dan; Wang, Yunqi; Rong, Lijun; Melton-Witt, Jody A; Freitag, Nancy E; Chen, Zheng W

    2008-08-01

    While recombinant Listeria monocytogenes strains can be explored as vaccine candidates, it is important to develop attenuated but highly immunogenic L. monocytogenes vaccine vectors. Here, prfA* mutations selected on the basis of upregulated expression of L. monocytogenes PrfA-dependent genes and proteins were assessed to determine their abilities to augment expression of foreign immunogens in recombinant L. monocytogenes vectors and therefore enhance vaccine-elicited immune responses (a prfA* mutation is a mutation that results in constitutive overexpression of PrfA and PrfA-dependent virulence genes; the asterisk distinguishes the mutation from inactivation or stop mutations). A total of 63 recombinant L. monocytogenes vaccine vectors expressing seven individual viral or bacterial immunogens each in nine different L. monocytogenes strains carrying wild-type prfA or having prfA* mutations were constructed and investigated. Mutations selected on the basis of increased PrfA activation in recombinant L. monocytogenes prfA* vaccine vectors augmented expression of seven individual protein immunogens remarkably. Consistently, prime and boost vaccination studies with mice indicated that the prfA(G155S) mutation in recombinant L. monocytogenes DeltaactA prfA* strains enhanced vaccine-elicited cellular immune responses. Surprisingly, the prfA(G155S) mutation was found to enhance vaccine-elicited humoral immune responses as well. The highly immunogenic recombinant L. monocytogenes DeltaactA prfA* vaccine strains were as attenuated as the recombinant parent L. monocytogenes DeltaactA vaccine vector. Thus, recombinant attenuated L. monocytogenes DeltaactA prfA* vaccine vectors potentially are better antimicrobial and anticancer vaccines.

  20. Developing Anti-tick Vaccines.

    PubMed

    Rodríguez-Mallon, Alina

    2016-01-01

    Ticks are responsible for the transmission of viral, bacterial, and protozoal diseases of man and animals and also produce significant economic losses to cattle industry. The use of acaricides constitutes a major component of integrated tick control strategies. However, this is accompanied by the selection of acaricide-resistant ticks and contamination of environment and milk and meat products with drug residues. These issues highlight the need for alternative approaches to control tick infestations and have triggered the search for tick protective antigens for vaccine development. Vaccination as a tick control method has been practiced since the introduction of TickGARD and Gavac that were developed using the midgut glycoprotein Bm86 as antigen. Gavac within integrated tick management systems has proven to reduce the number of acaricidal applications per year that are required to control some strains of R. microplus ticks in different geographical regions. Nevertheless, it has limited or no efficacy against other tick species. These issues have stimulated research for additional tick protective antigens with critical functions in the tick. This chapter presents methodologies for the design and test of molecules as antigens against ticks. Considerations about different methods for the tick control compared to the immunological methods, the desirable characteristics for an anti-tick vaccine and the obstacles encountered for developing this kind of vaccines are discussed. Detailed methodologies for the establishment of a biological model to test new molecules as immunogens against ticks and to perform challenge trials with this model are presented. General considerations in the efficacy calculation for any anti-tick vaccine are also discussed.

  1. Genome sequence of Bacillus anthracis attenuated vaccine strain A16R used for human in China.

    PubMed

    Liu, Xiankai; Qi, Xinpeng; Zhu, Li; Wang, Dongshu; Gao, Zhiqi; Deng, Haijun; Wu, Weili; Hu, Tao; Chen, Chen; Chen, Weijun; Wang, Hengliang

    2015-09-20

    An attenuated Bacillus anthracis vaccine strain for human use, A16R, was obtained in China after ultraviolet radiation treatment and continuous subculture of the wild-type strain A16. A16R can synthesize the exotoxin, but without a capsule. We sequenced and annotated the A16R genome to encourage the use of this strain. The genome sequencing of the wild-type strain A16 is underway and the genomic comparison between the two strains will help to illustrate the attenuating mechanism of the A16R vaccine strain.

  2. Prioritizing vaccines for developing world diseases.

    PubMed

    Saul, Allan; O'Brien, Katherine L

    2017-01-20

    A major disparity in the burden of health will need to be addressed to achieve the "Grand Convergence" by 2035. In particular people living in low and middle income countries have a much higher burden of infectious diseases. Although vaccines have been very effective in reducing the global burden of infectious disease, there are no registered vaccines to address 60% of the current burden of infectious disease, especially in developing countries. Thus there is a pressing need for new vaccines and for prioritizing vaccine development given that resources for developing new vaccines are strictly limited. As part of the GLOBAL HEALTH 2035: Mission Grand Convergence meeting one working group assessed the SMART vaccine algorithm as a mechanism for prioritizing vaccine development for diseases of priority in the developing world. In particular, the working group considered which criteria in the standard SMART set were considered "key" criteria and whether other criteria should be considered, when prioritizing vaccines for this important set of countries.

  3. A Recombinant Respiratory Syncytial Virus Vaccine Candidate Attenuated by a Low-Fusion F Protein Is Immunogenic and Protective against Challenge in Cotton Rats

    PubMed Central

    Rostad, Christina A.; Stobart, Christopher C.; Gilbert, Brian E.; Pickles, Ray J.; Hotard, Anne L.; Meng, Jia; Blanco, Jorge C. G.; Moin, Syed M.; Graham, Barney S.; Piedra, Pedro A.

    2016-01-01

    ABSTRACT Although respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants, a safe and effective vaccine is not yet available. Live-attenuated vaccines (LAVs) are the most advanced vaccine candidates in RSV-naive infants. However, designing an LAV with appropriate attenuation yet sufficient immunogenicity has proven challenging. In this study, we implemented reverse genetics to address these obstacles with a multifaceted LAV design that combined the codon deoptimization of genes for nonstructural proteins NS1 and NS2 (dNS), deletion of the small hydrophobic protein (ΔSH) gene, and replacement of the wild-type fusion (F) protein gene with a low-fusion RSV subgroup B F consensus sequence of the Buenos Aires clade (BAF). This vaccine candidate, RSV-A2-dNS-ΔSH-BAF (DB1), was attenuated in two models of primary human airway epithelial cells and in the upper and lower airways of cotton rats. DB1 was also highly immunogenic in cotton rats and elicited broadly neutralizing antibodies against a diverse panel of recombinant RSV strains. When vaccinated cotton rats were challenged with wild-type RSV A, DB1 reduced viral titers in the upper and lower airways by 3.8 log10 total PFU and 2.7 log10 PFU/g of tissue, respectively, compared to those in unvaccinated animals (P < 0.0001). DB1 was thus attenuated, highly immunogenic, and protective against RSV challenge in cotton rats. DB1 is the first RSV LAV to incorporate a low-fusion F protein as a strategy to attenuate viral replication and preserve immunogenicity. IMPORTANCE RSV is a leading cause of infant hospitalizations and deaths. The development of an effective vaccine for this high-risk population is therefore a public health priority. Although live-attenuated vaccines have been safely administered to RSV-naive infants, strategies to balance vaccine attenuation with immunogenicity have been elusive. In this study, we introduced a novel strategy to attenuate a recombinant RSV

  4. Safety, tolerability, and immunogenicity of a recombinant, genetically engineered, live-attenuated vaccine against canine blastomycosis.

    PubMed

    Wüthrich, Marcel; Krajaejun, Theerapong; Shearn-Bochsler, Valerie; Bass, Chris; Filutowicz, Hanna I; Legendre, Alfred M; Klein, Bruce S

    2011-05-01

    Blastomycosis is a severe, commonly fatal infection caused by the dimorphic fungus Blastomyces dermatitidis in dogs that live in the United States, Canada, and parts of Africa. The cost of treating an infection can be expensive, and no vaccine against this infection is commercially available. A genetically engineered live-attenuated strain of B. dermatitidis lacking the major virulence factor BAD-1 successfully vaccinates against lethal experimental infection in mice. Here we studied the safety, toxicity, and immunogenicity of this strain as a vaccine in dogs, using 25 beagles at a teaching laboratory and 78 foxhounds in a field trial. In the beagles, escalating doses of live vaccine ranging from 2 × 10⁴ to 2 × 10⁷ yeast cells given subcutaneously were safe and did not disseminate to the lung or induce systemic illness, but a dose of < 2 × 10⁶ yeast cells induced less fever and local inflammation. A vaccine dose of 10⁵ yeast cells was also well tolerated in vaccinated foxhounds who had never had blastomycosis; however, vaccinated dogs with prior infection had more local reactions at the vaccine site. The draining lymph node cells and peripheral blood lymphocytes from vaccinated dogs demonstrated gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) specifically in response to stimulation with Blastomyces antigens. Thus, the live-attenuated vaccine against blastomycosis studied here proved safe, well tolerated, and immunogenic in dogs and merits further studies of vaccine efficacy.

  5. Mucosal immunization with an attenuated Salmonella vaccine partially protects white-tailed deer from chronic wasting disease.

    PubMed

    Goñi, Fernando; Mathiason, Candace K; Yim, Lucia; Wong, Kinlung; Hayes-Klug, Jeanette; Nalls, Amy; Peyser, Daniel; Estevez, Veronica; Denkers, Nathaniel; Xu, Jinfeng; Osborn, David A; Miller, Karl V; Warren, Robert J; Brown, David R; Chabalgoity, Jose A; Hoover, Edward A; Wisniewski, Thomas

    2015-01-29

    Prion disease is a unique category of illness, affecting both animals and humans, in which the underlying pathogenesis is related to a conformational change of a normal, self-protein called PrP(C) (C for cellular) to a pathological and infectious conformer known as PrP(Sc) (Sc for scrapie). Bovine spongiform encephalopathy (BSE), a prion disease believed to have arisen from feeding cattle with prion contaminated meat and bone meal products, crossed the species barrier to infect humans. Chronic wasting disease (CWD) infects large numbers of deer and elk, with the potential to infect humans. Currently no prionosis has an effective treatment. Previously, we have demonstrated we could prevent transmission of prions in a proportion of susceptible mice with a mucosal vaccine. In the current study, white-tailed deer were orally inoculated with attenuated Salmonella expressing PrP, while control deer were orally inoculated with vehicle attenuated Salmonella. Once a mucosal response was established, the vaccinated animals were boosted orally and locally by application of polymerized recombinant PrP onto the tonsils and rectal mucosa. The vaccinated and control animals were then challenged orally with CWD-infected brain homogenate. Three years post CWD oral challenge all control deer developed clinical CWD (median survival 602 days), while among the vaccinated there was a significant prolongation of the incubation period (median survival 909 days; p=0.012 by Weibull regression analysis) and one deer has remained CWD free both clinically and by RAMALT and tonsil biopsies. This negative vaccinate has the highest titers of IgA in saliva and systemic IgG against PrP. Western blots showed that immunoglobulins from this vaccinate react to PrP(CWD). We document the first partially successful vaccination for a prion disease in a species naturally at risk.

  6. Mucosal Immunization with an Attenuated Salmonella Vaccine Partially Protects White-Tailed Deer from Chronic Wasting Disease

    PubMed Central

    Goñi, Fernando; Mathiason, Candace K.; Yim, Lucia; Wong, Kinlung; Hayes-Klug, Jeanette; Nalls, Amy; Peyser, Daniel; Estevez, Veronica; Denkers, Nathaniel; Xu, Jinfeng; Osborn, David A.; Miller, Karl V.; Warren, Robert J.; Brown, David R.; Chabalgoity, Jose A.; Hoover, Edward A.; Wisniewski, Thomas

    2014-01-01

    Prion disease is a unique category of illness, affecting both animals and humans, in which the underlying pathogenesis is related to a conformational change of a normal, self-protein called PrPC (C for cellular) to a pathological and infectious conformer known as PrPSc (Sc for scrapie). Bovine spongiform encephalopathy (BSE), a prion disease believed to have arisen from feeding cattle with prion contaminated meat and bone meal products, crossed the species barrier to infect humans. Chronic wasting disease (CWD) infects large numbers of deer and elk, with the potential to infect humans. Currently no prionosis has an effective treatment. Previously, we have demonstrated we could prevent transmission of prions in a proportion of susceptible mice with a mucosal vaccine. In the current study, white-tailed deer were orally inoculated with attenuated Salmonella expressing PrP, while control deer were orally inoculated with vehicle attenuated Salmonella. Once a mucosal response was established, the vaccinated animals were boosted orally and locally by application of polymerized recombinant PrP onto the tonsils and rectal mucosa. The vaccinated and control animals were then challenged orally with CWD-infected brain homogenate. Three years post CWD oral challenge all control deer developed clinical CWD (median survival 602 days), while among the vaccinated there was a significant prolongation of the incubation period (median survival 909 days; p=0.012 by Weibull regression analysis) and one deer has remained CWD free both clinically and by RAMALT and tonsil biopsies. This negative vaccinate has the highest titers of IgA in saliva and systemic IgG against PrP. Western blots showed that immunoglobulins from this vaccinate react to PrPCWD. We document the first partially successful vaccination for a prion disease in a species naturally at risk. PMID:25539804

  7. Novel adjuvants & delivery vehicles for vaccines development: a road ahead.

    PubMed

    Mohan, Teena; Verma, Priyanka; Rao, D Nageswara

    2013-11-01

    The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines.

  8. Novel adjuvants & delivery vehicles for vaccines development: A road ahead

    PubMed Central

    Mohan, Teena; Verma, Priyanka; Rao, D. Nageswara

    2013-01-01

    The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines. PMID:24434331

  9. Attenuated Recombinant Influenza A Virus Expressing HPV16 E6 and E7 as a Novel Therapeutic Vaccine Approach

    PubMed Central

    Jindra, Christoph; Huber, Bettina; Shafti-Keramat, Saeed; Wolschek, Markus; Ferko, Boris; Muster, Thomas; Brandt, Sabine; Kirnbauer, Reinhard

    2015-01-01

    Persistent infection with high-risk human papillomavirus (HPV) types, most often HPV16 and HPV18, causes all cervical and most anal cancers, and a subset of vulvar, vaginal, penile and oropharyngeal carcinomas. Two prophylactic virus-like particle (VLPs)-based vaccines, are available that protect against vaccine type-associated persistent infection and associated disease, yet have no therapeutic effect on existing lesions or infections. We have generated recombinant live-attenuated influenza A viruses expressing the HPV16 oncogenes E6 and E7 as experimental immunotherapeutic vaccine candidates. The influenza A virus life cycle lacks DNA intermediates as important safety feature. Different serotypes were generated to ensure efficient prime and boost immunizations. The immune response to vaccination in C57BL/6 mice was characterized by peptide ELISA and IFN-γ ELISpot, demonstrating induction of cell-mediated immunity to HPV16 E6 and E7 oncoproteins. Prophylactic and therapeutic vaccine efficacy was analyzed in the murine HPV16-positive TC-1 tumor challenge model. Subcutaneous (s.c.) prime and boost vaccinations of mice with recombinant influenza A serotypes H1N1 and H3N2, followed by challenge with TC-1 cells resulted in complete protection or significantly reduced tumor growth as compared to control animals. In a therapeutic setting, s.c. vaccination of mice with established TC-1 tumors decelerated tumor growth and significantly prolonged survival. Importantly, intralesional vaccine administration induced complete tumor regression in 25% of animals, and significantly reduced tumor growth in 50% of mice. These results suggest recombinant E6E7 influenza viruses as a promising new approach for the development of a therapeutic vaccine against HPV-induced disease. PMID:26381401

  10. A Live Attenuated Equine H3N8 Influenza Vaccine Is Highly Immunogenic and Efficacious in Mice and Ferrets

    PubMed Central

    Baz, Mariana; Paskel, Myeisha; Matsuoka, Yumiko; Zengel, James; Cheng, Xing; Treanor, John J.; Jin, Hong

    2014-01-01

    ABSTRACT Equine influenza viruses (EIV) are responsible for rapidly spreading outbreaks of respiratory disease in horses. Although natural infections of humans with EIV have not been reported, experimental inoculation of humans with these viruses can lead to a productive infection and elicit a neutralizing antibody response. Moreover, EIV have crossed the species barrier to infect dogs, pigs, and camels and therefore may also pose a threat to humans. Based on serologic cross-reactivity of H3N8 EIV from different lineages and sublineages, A/equine/Georgia/1/1981 (eq/GA/81) was selected to produce a live attenuated candidate vaccine by reverse genetics with the hemagglutinin and neuraminidase genes of the eq/GA/81 wild-type (wt) virus and the six internal protein genes of the cold-adapted (ca) A/Ann Arbor/6/60 (H2N2) vaccine donor virus, which is the backbone of the licensed seasonal live attenuated influenza vaccine. In both mice and ferrets, intranasal administration of a single dose of the eq/GA/81 ca vaccine virus induced neutralizing antibodies and conferred complete protection from homologous wt virus challenge in the upper respiratory tract. One dose of the eq/GA/81 ca vaccine also induced neutralizing antibodies and conferred complete protection in mice and nearly complete protection in ferrets upon heterologous challenge with the H3N8 (eq/Newmarket/03) wt virus. These data support further evaluation of the eq/GA/81 ca vaccine in humans for use in the event of transmission of an equine H3N8 influenza virus to humans. IMPORTANCE Equine influenza viruses have crossed the species barrier to infect other mammals such as dogs, pigs, and camels and therefore may also pose a threat to humans. We believe that it is important to develop vaccines against equine influenza viruses in the event that an EIV evolves, adapts, and spreads in humans, causing disease. We generated a live attenuated H3N8 vaccine candidate and demonstrated that the vaccine was immunogenic and

  11. Construction of a live-attenuated HIV-1 vaccine through genetic code expansion.

    PubMed

    Wang, Nanxi; Li, Yue; Niu, Wei; Sun, Ming; Cerny, Ronald; Li, Qingsheng; Guo, Jiantao

    2014-05-05

    A safe and effective vaccine against human immunodeficiency virus type 1 (HIV-1) is urgently needed to combat the worldwide AIDS pandemic, but still remains elusive. The fact that uncontrolled replication of an attenuated vaccine can lead to regaining of its virulence creates safety concerns precluding many vaccines from clinical application. We introduce a novel approach to control HIV-1 replication, which entails the manipulation of essential HIV-1 protein biosynthesis through unnatural amino acid (UAA*)-mediated suppression of genome-encoded blank codon. We successfully demonstrate that HIV-1 replication can be precisely turned on and off in vitro.

  12. Live attenuated measles and mumps viral strain-containing vaccines and hearing loss: Vaccine Adverse Event Reporting System (VAERS), United States, 1990--2003.

    PubMed

    Asatryan, Armenak; Pool, Vitali; Chen, Robert T; Kohl, Katrin S; Davis, Robert L; Iskander, John K

    2008-02-26

    Hearing loss (HL) is a known complication of wild measles and mumps viral infections. As vaccines against measles and mumps contain live attenuated viral strains, it is biologically plausible that in some individuals HL could develop as a complication of vaccination against measles and/or mumps. Our objectives for this study were: to find and describe all cases of HL reported in the scientific literature and to the US Vaccine Adverse Events Reporting System (VAERS) for the period 1990--2003; and to determine reporting rate of HL after live attenuated measles and/or mumps viral strain-containing vaccines (MMCV) administration. We searched published reports for cases of HL identified after vaccination with MMCV. We also searched for reports of HL after MMCV administration submitted to VAERS from 1990 through 2003 and determined the dose-adjusted reporting rate of HL. Our main outcome measure was reported cases of HL after immunization with MMCV which were classified as idiopathic. We found 11 published case reports of HL following MMCV. The review of the VAERS reports identified 44 cases of likely idiopathic sensorineural HL after MMCV administration. The onset of HL in the majority of VAERS and published cases was consistent with the incubation periods of wild measles and mumps viruses. Based on the annual usage of measles-mumps-rubella (MMR) vaccine, we estimated the reporting rate of HL to be 1 case per 6-8 million doses. Thus, HL following MMCV has been reported in the literature and to the VAERS. Further studies are needed to better understand if there is a causal relationship between MMCV and HL.

  13. Plague Vaccine Development: Current Research and Future Trends

    PubMed Central

    Verma, Shailendra Kumar; Tuteja, Urmil

    2016-01-01

    Plague is one of the world’s most lethal human diseases caused by Yersinia pestis, a Gram-negative bacterium. Despite overwhelming studies for many years worldwide, there is no safe and effective vaccine against this fatal disease. Inhalation of Y. pestis bacilli causes pneumonic plague, a fast growing and deadly dangerous disease. F1/LcrV-based vaccines failed to provide adequate protection in African green monkey model in spite of providing protection in mice and cynomolgus macaques. There is still no explanation for this inconsistent efficacy, and scientists leg behind to search reliable correlate assays for immune protection. These paucities are the main barriers to improve the effectiveness of plague vaccine. In the present scenario, one has to pay special attention to elicit strong cellular immune response in developing a next-generation vaccine against plague. Here, we review the scientific contributions and existing progress in developing subunit vaccines, the role of molecular adjuvants; DNA vaccines; live delivery platforms; and attenuated vaccines developed to counteract virulent strains of Y. pestis. PMID:28018363

  14. Multicenter Safety and Immunogenicity Trial of an Attenuated Measles Vaccine for NHP.

    PubMed

    Yee, Joann L; McChesney, Michael B; Christe, Kari L

    2015-10-01

    Measles is a highly contagious viral disease in NHP. The infection can range from asymptomatic to rapidly fatal, resulting in significant morbidity and mortality in captive populations. In addition to appropriate quarantine practices, restricted access, the immunization of all personnel in contact with NHP, and the wearing of protective clothing including face masks, measles immunization further reduces the infection risk. Commercially available measles vaccines are effective for use in NHP, but interruptions in their availability have prevented the implementation of ongoing, consistent vaccination programs. This need for a readily available vaccine led us to perform a broad, multicenter safety and immunogenicity study of another candidate vaccine, MVac (Serum Institute of India), a monovalent measles vaccine derived from live Edmonston-Zagreb strain virus that had been attenuated after 22 passages on human diploid cells.

  15. Multicenter Safety and Immunogenicity Trial of an Attenuated Measles Vaccine for NHP

    PubMed Central

    Yee, JoAnn L; McChesney, Michael B; Christe, Kari L

    2015-01-01

    Measles is a highly contagious viral disease in NHP. The infection can range from asymptomatic to rapidly fatal, resulting in significant morbidity and mortality in captive populations. In addition to appropriate quarantine practices, restricted access, the immunization of all personnel in contact with NHP, and the wearing of protective clothing including face masks, measles immunization further reduces the infection risk. Commercially available measles vaccines are effective for use in NHP, but interruptions in their availability have prevented the implementation of ongoing, consistent vaccination programs. This need for a readily available vaccine led us to perform a broad, multicenter safety and immunogenicity study of another candidate vaccine, MVac (Serum Institute of India), a monovalent measles vaccine derived from live Edmonston–Zagreb strain virus that had been attenuated after 22 passages on human diploid cells. PMID:26473350

  16. Recent advances in the study of live attenuated cell-cultured smallpox vaccine LC16m8.

    PubMed

    Eto, Akiko; Saito, Tomoya; Yokote, Hiroyuki; Kurane, Ichiro; Kanatani, Yasuhiro

    2015-11-09

    LC16m8 is a live, attenuated, cell-cultured smallpox vaccine that was developed and licensed in Japan in the 1970s, but was not used in the campaign to eradicate smallpox. In the early 2000s, the potential threat of bioterrorism led to reconsideration of the need for a smallpox vaccine. Subsequently, LC16m8 production was restarted in Japan in 2002, requiring re-evaluation of its safety and efficacy. Approximately 50,000 children in the 1970s and about 3500 healthy adults in the 2000s were vaccinated with LC16m8 in Japan, and 153 adults have been vaccinated with LC16m8 or Dryvax in phase I/II clinical trials in the USA. These studies confirmed the safety and efficacy of LC16m8, while several studies in animal models have shown that LC16m8 protects the host against viral challenge. The World Health Organization Strategic Advisory Group of Experts on Immunization recommended LC16m8, together with ACAM2000, as a stockpile vaccine in 2013. In addition, LC16m8 is expected to be a viable alternative to first-generation smallpox vaccines to prevent human monkeypox.

  17. Vaccination using radiation- or genetically attenuated live sporozoites.

    PubMed

    Vaughan, Ashley M; Kappe, Stefan H I

    2013-01-01

    The attenuation of Plasmodium parasites by either radiation or targeted gene deletion can result in viable sporozoites that invade the liver and subsequently arrest. The death of the growth-arrested liver stage parasite and the ensuing recognition by the immune system of parasite antigens promotes protective immunity in immunized mice and humans. The methods described below will enable researchers to determine the efficacy of radiation-attenuated and genetically attenuated rodent malaria sporozoite immunizations against infectious sporozoite challenge, and study protective immunity in immunized mice. In addition, by determining the time of arrest of genetically attenuated parasite liver stages and the mechanisms of clearance, researchers will be able to correlate biological features of the growth-arrested parasites with their ability to promote protective immunity.

  18. Reversion of Cold-Adapted Live Attenuated Influenza Vaccine into a Pathogenic Virus

    PubMed Central

    Meliopoulos, Victoria A.; Wang, Wei; Lin, Xudong; Stucker, Karla M.; Halpin, Rebecca A.; Stockwell, Timothy B.; Schultz-Cherry, Stacey

    2016-01-01

    ABSTRACT The only licensed live attenuated influenza A virus vaccines (LAIVs) in the United States (FluMist) are created using internal protein-coding gene segments from the cold-adapted temperature-sensitive master donor virus A/Ann Arbor/6/1960 and HA/NA gene segments from circulating viruses. During serial passage of A/Ann Arbor/6/1960 at low temperatures to select the desired attenuating phenotypes, multiple cold-adaptive mutations and temperature-sensitive mutations arose. A substantial amount of scientific and clinical evidence has proven that FluMist is safe and effective. Nevertheless, no study has been conducted specifically to determine if the attenuating temperature-sensitive phenotype can revert and, if so, the types of substitutions that will emerge (i.e., compensatory substitutions versus reversion of existing attenuating mutations). Serial passage of the monovalent FluMist 2009 H1N1 pandemic vaccine at increasing temperatures in vitro generated a variant that replicated efficiently at higher temperatures. Sequencing of the variant identified seven nonsynonymous mutations, PB1-E51K, PB1-I171V, PA-N350K, PA-L366I, NP-N125Y, NP-V186I, and NS2-G63E. None occurred at positions previously reported to affect the temperature sensitivity of influenza A viruses. Synthetic genomics technology was used to synthesize the whole genome of the virus, and the roles of individual mutations were characterized by assessing their effects on RNA polymerase activity and virus replication kinetics at various temperatures. The revertant also regained virulence and caused significant disease in mice, with severity comparable to that caused by a wild-type 2009 H1N1 pandemic virus. IMPORTANCE The live attenuated influenza vaccine FluMist has been proven safe and effective and is widely used in the United States. The phenotype and genotype of the vaccine virus are believed to be very stable, and mutants that cause disease in animals or humans have never been reported. By

  19. Evaluation of an attenuated strain of Ehrlichia canis as a vaccine for canine monocytic ehrlichiosis.

    PubMed

    Rudoler, Nir; Baneth, Gad; Eyal, Osnat; van Straten, Michael; Harrus, Shimon

    2012-12-17

    Canine monocytic ehrlichiosis is an important tick-borne disease worldwide. No commercial vaccine for the disease is currently available and tick control is the main preventive measure against the disease. The aim of this study was to evaluate the potential of a multi-passaged attenuated strain of Ehrlichia canis to serve as a vaccine for canine monocytic ehrlichiosis, and to assess the use of azithromycin in the treatment of acute ehrlichiosis. Twelve beagle dogs were divided into 3 groups of 4 dogs. Groups 1 and 2 were inoculated (vaccinated) with an attenuated strain of E. canis (#611A) twice or once, respectively. The third group consisted of naïve dogs which served as controls. All 3 groups were challenged with a wild virulent strain of E. canis by administering infected dog-blood intravenously. Transient thrombocytopenia was the only hematological abnormality observed following inoculation of dogs with the attenuated strain. Challenge with the virulent strain resulted in severe disease in all 4 control dogs while only 3 of 8 vaccinated dogs presented mild transient fever. Furthermore, the mean blood rickettsial load was significantly higher in the control group (27-92-folds higher during days 14-19 post challenge with the wild the strain) as compared to the vaccinated dogs. The use of azithromycin was assessed as a therapeutic agent for the acute disease. Four days treatment resulted in further deterioration of the clinical condition of the dogs. Molecular comparison of 4 genes known to express immunoreactive proteins and virulence factors (p30, gp19, VirB4 and VirB9) between the attenuated strain and the challenge wild strain revealed no genetic differences between the strains. The results of this study indicate that the attenuated E. canis strain may serve as an effective and secure future vaccine for canine ehrlichiosis.

  20. Distinct Cross-reactive B-Cell Responses to Live Attenuated and Inactivated Influenza Vaccines

    PubMed Central

    Sasaki, Sanae; Holmes, Tyson H.; Albrecht, Randy A.; García-Sastre, Adolfo; Dekker, Cornelia L.; He, Xiao-Song; Greenberg, Harry B.

    2014-01-01

    Background. The immunological bases for the efficacies of the 2 currently licensed influenza vaccines, live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV), are not fully understood. The goal of this study was to identify specific B-cell responses correlated with the known efficacies of these 2 vaccines. Methods. We compared the B-cell and antibody responses after immunization with 2010/2011 IIV or LAIV in young adults, focusing on peripheral plasmablasts 6–8 days after vaccination. Results. The quantities of vaccine-specific plasmablasts and plasmablast-derived polyclonal antibodies (PPAbs) in IIV recipients were significantly higher than those in LAIV recipients. No significant difference was detected in the avidity of vaccine-specific PPAbs between the 2 vaccine groups. Proportionally, LAIV induced a greater vaccine-specific immunoglobulin A plasmablast response, as well as a greater plasmablast response to the conserved influenza nuclear protein, than IIV. The cross-reactive plasmablast response to heterovariant strains, as indicated by the relative levels of cross-reactive plasmablasts and the cross-reactive PPAb binding reactivity, was also greater in the LAIV group. Conclusions. Distinct quantitative and qualitative patterns of plasmablast responses were induced by LAIV and IIV in young adults; a proportionally greater cross-reactive response was induced by LAIV. PMID:24676204

  1. WHO working group on the quality, safety and efficacy of japanese encephalitis vaccines (live attenuated) for human use, Bangkok, Thailand, 21-23 February 2012.

    PubMed

    Trent, Dennis W; Minor, Philip; Jivapaisarnpong, Teeranart; Shin, Jinho

    2013-11-01

    Japanese encephalitis (JE) is one of the most important viral encephalitides in Asia. Two live-attenuated vaccines have been developed and licensed for use in countries in the region. Given the advancement of immunization of humans with increasing use of live-attenuated vaccines to prevent JE, there is increased interest to define quality standards for their manufacture, testing, nonclinical studies, and clinical studies to assess their efficacy and safety in humans. To this end, WHO convened a meeting with a group of international experts in February 2012 to develop guidelines for evaluating the quality, safety and efficacy of live-attenuated JE virus vaccines for prevention of human disease. This report summarizes collective views of the participants on scientific and technical issues that need to be considered in the guidelines.

  2. Use of Prior Vaccinations for the Development of New Vaccines

    NASA Astrophysics Data System (ADS)

    Etlinger, H. M.; Gillessen, D.; Lahm, H.-W.; Matile, H.; Schonfeld, H.-J.; Trzeciak, A.

    1990-07-01

    There is currently a need for vaccine development to improve the immunogenicity of protective epitopes, which themselves are often poorly immunogenic. Although the immunogenicity of these epitopes can be enhanced by linking them to highly immunogenic carriers, such carriers derived from current vaccines have not proven to be generally effective. One reason may be related to epitope-specific suppression, in which prior vaccination with a protein can inhibit the antibody response to new epitopes linked to the protein. To circumvent such inhibition, a peptide from tetanus toxoid was identified that, when linked to a B cell epitope and injected into tetanus toxoid-primed recipients, retained sequences for carrier but not suppressor function. The antibody response to the B cell epitope was enhanced. This may be a general method for taking advantage of previous vaccinations in the development of new vaccines.

  3. Status of vaccine research and development for Shigella.

    PubMed

    Mani, Sachin; Wierzba, Thomas; Walker, Richard I

    2016-06-03

    Shigella are gram-negative bacteria that cause severe diarrhea and dysentery. In 2013, Shigella infections caused an estimated 34,400 deaths in children less than five years old and, in 2010, an estimated 40,000 deaths in persons older than five years globally. New disease burden estimates from newly deployed molecular diagnostic assays with increased sensitivity suggest that Shigella-associated morbidity may be much greater than previous disease estimates from culture-based methods. Primary prevention of this disease should be based on universal provision of potable water and sanitation methods and improved personal and food hygiene. However, an efficacious and low-cost vaccine would complement and accelerate disease reduction while waiting for universal access to water, sanitation, and hygiene improvements. This review article provides a landscape of Shigella vaccine development efforts. No vaccine is yet available, but human and animal challenge-rechallenge trials with virulent Shigella as well as observational studies in Shigella-endemic areas have shown that the incidence of disease decreases following Shigella infection, pointing to biological feasibility of a vaccine. Immunity to Shigella appears to be strain-specific, so a vaccine that covers the most commonly detected strains (i.e., S. flexneri 2a, 3a, 6, and S. sonnei) or a vaccine using cross-species conserved antigens would likely be most effective. Vaccine development and testing may be accelerated by use of animal models, such as the guinea pig keratoconjunctivitis or murine pneumonia models. Because there is no correlate of protection, however, human studies will be necessary to evaluate vaccine efficacy prior to deployment. A diversity of Shigella vaccine constructs are under development, including live attenuated, formalin-killed whole-cell, glycoconjugate, subunit, and novel antigen vaccines (e.g., Type III secretion system and outer membrane proteins).

  4. Engineering and Preclinical Evaluation of Attenuated Nontyphoidal Salmonella Strains Serving as Live Oral Vaccines and as Reagent Strains▿†

    PubMed Central

    Tennant, Sharon M.; Wang, Jin-Yuan; Galen, James E.; Simon, Raphael; Pasetti, Marcela F.; Gat, Orit; Levine, Myron M.

    2011-01-01

    While nontyphoidal Salmonella (NTS) has long been recognized as a cause of self-limited gastroenteritis, it is becoming increasingly evident that multiple-antibiotic-resistant strains are also emerging as important causes of invasive bacteremia and focal infections, resulting in hospitalizations and deaths. We have constructed attenuated Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains that can serve as live oral vaccines and as “reagent strains” for subunit vaccine production in a safe and economical manner. Prototype attenuated vaccine strains CVD 1921 and CVD 1941, derived from the invasive wild-type strains S. Typhimurium I77 and S. Enteritidis R11, respectively, were constructed by deleting guaBA, encoding guanine biosynthesis, and clpP, encoding a master protease regulator. The clpP mutation resulted in a hyperflagellation phenotype. An additional deletion in fliD yielded reagent strains CVD 1923 and CVD 1943, respectively, which export flagellin monomers. Oral 50% lethal dose (LD50) analyses showed that the NTS vaccine strains were all highly attenuated in mice. Oral immunization with CVD 1921 or CVD 1923 protected mice against lethal challenge with wild-type S. Typhimurium I77. Immunization with CVD 1941 but not CVD 1943 protected mice against lethal infection with S. Enteritidis R11. Immune responses induced by these strains included high levels of serum IgG anti-lipopolysaccharide (LPS) and anti-flagellum antibodies, with titers increasing progressively during the immunization schedule. Since S. Typhimurium and S. Enteritidis are the most common NTS serovars associated with invasive disease, these findings can pave the way for development of a highly effective, broad-spectrum vaccine against invasive NTS. PMID:21807911

  5. Vaccination With a Highly Attenuated Recombinant Vesicular Stomatitis Virus Vector Protects Against Challenge With a Lethal Dose of Ebola Virus.

    PubMed

    Matassov, Demetrius; Marzi, Andrea; Latham, Terri; Xu, Rong; Ota-Setlik, Ayuko; Feldmann, Friederike; Geisbert, Joan B; Mire, Chad E; Hamm, Stefan; Nowak, Becky; Egan, Michael A; Geisbert, Thomas W; Eldridge, John H; Feldmann, Heinz; Clarke, David K

    2015-10-01

    Previously, recombinant vesicular stomatitis virus (rVSV) pseudotypes expressing Ebolavirus glycoproteins (GPs) in place of the VSV G protein demonstrated protection of nonhuman primates from lethal homologous Ebolavirus challenge. Those pseudotype vectors contained no additional attenuating mutations in the rVSV genome. Here we describe rVSV vectors containing a full complement of VSV genes and expressing the Ebola virus (EBOV) GP from an additional transcription unit. These rVSV vectors contain the same combination of attenuating mutations used previously in the clinical development pathway of an rVSV/human immunodeficiency virus type 1 vaccine. One of these rVSV vectors (N4CT1-EBOVGP1), which expresses membrane-anchored EBOV GP from the first position in the genome (GP1), elicited a balanced cellular and humoral GP-specific immune response in mice. Guinea pigs immunized with a single dose of this vector were protected from any signs of disease following lethal EBOV challenge, while control animals died in 7-9 days. Subsequently, N4CT1-EBOVGP1 demonstrated complete, single-dose protection of 2 macaques following lethal EBOV challenge. A single sham-vaccinated macaque died from disease due to EBOV infection. These results demonstrate that highly attenuated rVSV vectors expressing EBOV GP may provide safer alternatives to current EBOV vaccines.

  6. Vaccination With a Highly Attenuated Recombinant Vesicular Stomatitis Virus Vector Protects Against Challenge With a Lethal Dose of Ebola Virus

    PubMed Central

    Matassov, Demetrius; Marzi, Andrea; Latham, Terri; Xu, Rong; Ota-Setlik, Ayuko; Feldmann, Friederike; Geisbert, Joan B.; Mire, Chad E.; Hamm, Stefan; Nowak, Becky; Egan, Michael A.; Geisbert, Thomas W.; Eldridge, John H.; Feldmann, Heinz; Clarke, David K.

    2015-01-01

    Previously, recombinant vesicular stomatitis virus (rVSV) pseudotypes expressing Ebolavirus glycoproteins (GPs) in place of the VSV G protein demonstrated protection of nonhuman primates from lethal homologous Ebolavirus challenge. Those pseudotype vectors contained no additional attenuating mutations in the rVSV genome. Here we describe rVSV vectors containing a full complement of VSV genes and expressing the Ebola virus (EBOV) GP from an additional transcription unit. These rVSV vectors contain the same combination of attenuating mutations used previously in the clinical development pathway of an rVSV/human immunodeficiency virus type 1 vaccine. One of these rVSV vectors (N4CT1-EBOVGP1), which expresses membrane-anchored EBOV GP from the first position in the genome (GP1), elicited a balanced cellular and humoral GP-specific immune response in mice. Guinea pigs immunized with a single dose of this vector were protected from any signs of disease following lethal EBOV challenge, while control animals died in 7–9 days. Subsequently, N4CT1-EBOVGP1 demonstrated complete, single-dose protection of 2 macaques following lethal EBOV challenge. A single sham-vaccinated macaque died from disease due to EBOV infection. These results demonstrate that highly attenuated rVSV vectors expressing EBOV GP may provide safer alternatives to current EBOV vaccines. PMID:26109675

  7. Reversion to virulence and efficacy of an attenuated canarypox vaccine in Hawai'i 'Amakihi (Hemignathus Virens)

    USGS Publications Warehouse

    Atkinson, Carter T.; Wiegand, Kimberly C.; Triglia, Dennis; Jarvi, Susan I.

    2012-01-01

    Vaccines may be effective tools for protecting small populations of highly susceptible endangered, captive-reared, or translocated Hawaiian honeycreepers from introduced Avipoxvirus, but their efficacy has not been evaluated. An attenuated Canarypox vaccine that is genetically similar to one of two passerine Avipoxvirus isolates from Hawai‘i and distinct from Fowlpox was tested to evaluate whether Hawai‘i ‘Amakihi (Hemignathus virens) can be protected from wild isolates of Avipoxvirus from the Hawaiian Islands. Thirty-one (31) Hawai‘i ‘Amakihi were collected from high-elevation habitats on Mauna Kea Volcano, where pox transmission is rare, and randomly divided into two groups. One group was vaccinated with Poximune C®, whereas the other group received a sham vaccination with sterile water. Four of 15 (27%) vaccinated birds developed life-threatening disseminated lesions or lesions of unusually long duration, whereas one bird never developed a vaccine-associated lesion or “take.” After vaccine lesions healed, vaccinated birds were randomly divided into three groups of five and challenged with either a wild isolate of Fowlpox (FP) from Hawai‘i, a Hawai‘i ‘Amakihi isolate of a Canarypox-like virus (PV1), or a Hawai‘i ‘Amakihi isolate of a related, but distinct, passerine Avipoxvirus (PV2). Similarly, three random groups of five unvaccinated ‘Amakihi were challenged with the same virus isolates. Vaccinated and unvaccinated ‘Amakihi challenged with FP had transient infections with no clinical signs of infection. Mortality in vaccinated ‘Amakihi challenged with PV1 and PV2 ranged from 0% (0/5) for PV1 to 60% (3/5) for PV2. Mortality in unvaccinated ‘Amakihi ranged from 40% (2/5) for PV1 to 100% (5/5) for PV2. Although the vaccine provided some protection against PV1, both potential for vaccine reversion and low efficacy against PV2 preclude its use in captive or wild honeycreepers.

  8. Protection induced by a glycoprotein E-deleted bovine herpesvirus type 1 marker strain used either as an inactivated or live attenuated vaccine in cattle

    PubMed Central

    2014-01-01

    Background Bovine herpesvirus type 1 (BoHV-1) is the causative agent of respiratory and genital tract infections; causing a high economic loss in all continents. Use of marker vaccines in IBR eradication programs is widely accepted since it allows for protection of the animals against the disease while adding the possibility of differentiating vaccinated from infected animals. The aim of the present study was the development and evaluation of safety and efficacy of a glycoprotein E-deleted (gE-) BoHV-1 marker vaccine strain (BoHV-1ΔgEβgal) generated by homologous recombination, replacing the viral gE gene with the β-galactosidase (βgal) gene. Results In vitro growth kinetics of the BoHV-1ΔgEβgal virus was similar to BoHV-1 LA. The immune response triggered by the new recombinant strain in cattle was characterized both as live attenuated vaccine (LAV) and as an inactivated vaccine. BoHV-1ΔgEβgal was highly immunogenic in both formulations, inducing specific humoral and cellular immune responses. Antibody titers found in animals vaccinated with the inactivated vaccine based on BoHV-1ΔgEβgal was similar to the titers found for the control vaccine (BoHV-1 LA). In the same way, titers of inactivated vaccine groups were significantly higher than any of the LAV immunized groups, independently of the inoculation route (p < 0.001). Levels of IFN-γ were significantly higher (p < 0.001) in those animals that received the LAV compared to those that received the inactivated vaccine. BoHV-1ΔgEβgal exhibited an evident attenuation when administered as a LAV; no virus was detected in nasal secretions of vaccinated or sentinel animals during the post-vaccination period. BoHV-1ΔgEβgal, when used in either formulation, elicited an efficient immune response that protected animals against challenge with virulent wild-type BoHV-1. Also, the deletion of the gE gene served as an immunological marker to differentiate vaccinated animals from infected animals. All

  9. A live attenuated cold-adapted influenza A H7N3 virus vaccine provides protection against homologous and heterologous H7 viruses in mice and ferrets

    SciTech Connect

    Joseph, Tomy; McAuliffe, Josephine; Lu, Bin; Vogel, Leatrice; Swayne, David; Jin, Hong; Kemble, George; Subbarao, Kanta

    2008-08-15

    The appearance of human infections caused by avian influenza A H7 subtype viruses underscores their pandemic potential and the need to develop vaccines to protect humans from viruses of this subtype. A live attenuated H7N3 virus vaccine was generated by reverse genetics using the HA and NA genes of a low pathogenicity A/chicken/BC/CN-6/04 (H7N3) virus and the six internal protein genes of the cold-adapted A/Ann Arbor/6/60 ca (H2N2) virus. The reassortant H7N3 BC 04 ca vaccine virus was temperature sensitive and showed attenuation in mice and ferrets. Intranasal immunization with one dose of the vaccine protected mice and ferrets when challenged with homologous and heterologous H7 viruses. The reassortant H7N3 BC 04 ca vaccine virus showed comparable levels of attenuation, immunogenicity and efficacy in mice and ferret models. The safety, immunogenicity, and efficacy of this vaccine in mice and ferrets support the evaluation of this vaccine in clinical trials.

  10. Global gene expression in channel catfish after vaccination with an attenuated Edwardsiella ictaluri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To understand the global gene expression in channel catfish after immersion vaccination with an attenuated Edwardsiella ictaluri (AquaVac ESCTM), microarray analysis of 65,182 UniGene transcripts were performed. With a filter of false-discovery rate less than 0.05 and fold change greater than 2, a t...

  11. A comparative study of live attenuated F strain-derived Mycoplasma gallisepticum vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercially available attenuated strains of Mycoplasma gallisepticum (MG) are commonly used within the layer industry to control MG-induced mycoplasmosis. Among these are two live MG vaccines derived from the moderately pathogenic MG “chick F” strain. In the present study, the commercially availa...

  12. Complete Genome Sequence of the Attenuated Novobiocin-Resistant Streptococcus iniae Vaccine Strain ISNO

    PubMed Central

    Zhang, Dunhua; Zhang, Lee

    2014-01-01

    Streptococcus iniae ISNO is an attenuated novobiocin-resistant vaccine strain. Its full genome is 2,070,182 bp in length. The availability of this genome will allow comparative genomics to identify potential virulence genes important for pathogenesis of S. iniae and potential mechanisms associated with novobiocin resistance in this strain. PMID:24874684

  13. Possibilities and challenges for developing a successful vaccine for leishmaniasis.

    PubMed

    Srivastava, Saumya; Shankar, Prem; Mishra, Jyotsna; Singh, Sarman

    2016-05-12

    Leishmaniasis is a vector-borne disease caused by different species of protozoan parasites of the genus Leishmania. It is a major health problem yet neglected tropical diseases, with approximately 350 million people worldwide at risk and more than 1.5 million infections occurring each year. Leishmaniasis has different clinical manifestations, including visceral (VL or kala-azar), cutaneous (CL), mucocutaneous (MCL), diffuse cutaneous (DCL) and post kala-azar dermal leishmaniasis (PKDL). Currently, the only mean to treat and control leishmaniasis is by rational medications and vector control. However, the number of available drugs is limited and even these are either exorbitantly priced, have toxic side effects or prove ineffective due to the emergence of resistant strains. On the other hand, the vector control methods are not so efficient. Therefore, there is an urgent need for developing a safe, effective, and affordable vaccine for the prevention of leishmaniasis. Although in recent years a large body of researchers has concentrated their efforts on this issue, yet only three vaccine candidates have gone for clinical trial, until date. These are: (i) killed vaccine in Brazil for human immunotherapy; (ii) live attenuated vaccine for humans in Uzbekistan; and (iii) second-generation vaccine for dog prophylaxis in Brazil. Nevertheless, there are at least half a dozen vaccine candidates in the pipeline. One can expect that, in the near future, the understanding of the whole genome of Leishmania spp. will expand the vaccine discovery and strategies that may provide novel vaccines. The present review focuses on the development and the status of various vaccines and potential vaccine candidates against leishmaniasis.

  14. Five-year antibody persistence in children after one dose of inactivated or live attenuated hepatitis A vaccine.

    PubMed

    Zhang, Zhilun; Zhu, Xiangjun; Hu, Yuansheng; Liang, Miao; Sun, Jin; Song, Yufei; Yang, Qi; Ji, Haiquan; Zeng, Gang; Song, Lifei; Chen, Jiangting

    2017-02-14

    In China, both inactivated hepatitis A (HA) vaccine and live attenuated HA vaccine are available. We conducted a trial to evaluate 5-year immune persistence induced by one dose of inactivated or live attenuated HA vaccines in children. Subjects with no HA vaccination history had randomly received one dose of inactivated or live attenuated HA vaccine at 18-60 months of age. Anti-HAV antibody concentrations were measured before vaccination and at the first, second, and fifth year after vaccination. Suspected cases of hepatitis A were monitored during the study period. A total of 332 subjects were enrolled and 182 provided evaluable serum samples at all planned time points. seropositive rate at 5 y was 85.9% in the inactivated HA vaccine group and 90.7% in the live attenuated HA vaccine group. GMCs were 76.3% mIU/ml (95% CI: 61.7 - 94.4) and 66.8mIU/ml (95% CI: 57.8 - 77.3), respectively. No significant difference in antibody persistence between 2 groups was found. No clinical hepatitis A case was reported. A single dose of an inactivated or live attenuated HA vaccine at 18-60 months of age resulted in high HAV seropositive rate and anti-HAV antibody concentrations that lasted for at least 5 y.

  15. Intratumoral injection of attenuated Salmonella vaccine can induce tumor microenvironmental shift from immune suppressive to immunogenic.

    PubMed

    Hong, Eun-Hye; Chang, Sun-Young; Lee, Bo-Ra; Pyun, A-Rim; Kim, Ji-Won; Kweon, Mi-Na; Ko, Hyun-Jeong

    2013-02-27

    Attenuated Salmonella vaccines show therapeutic anti-cancer effects, but the underlying mechanism has not been well investigated. In the current study, intratumoral (i.t.) injection of recombinant attenuated Salmonella enterica serovar Typhimurium vaccine (RASV) significantly inhibited Her-2/neu-expressing tumor growth. Although depletion of CD8(+) cells in RASV-treated mice significantly restored tumor growth, the induction of Her-2/neu-specific cytotoxic T lymphocytes (CTLs) was not well correlated with the generation of the anti-tumor effect. Therefore, we hypothesized that RASV might induce a tumor microenvironmental shift, from immune suppressive to immunogenic, to reduce the suppressive force and finally elicit a successful anti-tumor response. We found that i.t. injection of RASV significantly increased the level of CD11b(+)Gr-1(+) myeloid cells identified as myeloid-derived suppressor cell (MDSC), but a significant portion of these cells were TNF-α-secreting Ly6-G(high) subsets, which can function as antitumor effector cells. We further investigated whether RASV can modulate immunosuppressive Treg cells, and CD4(+)CD25(+) Foxp3(+) Tregs was significantly reduced in RASV-treated mice. Thus, i.t. injection of RASV may offer a novel anti-cancer approach by eliciting transformation of immunosuppressive MDSCs into TNF-α-secreting neutrophils and reducing the generation of Treg cells, especially in the presence of tumor-specific CTLs. Collectively, these data will provide us an insight for the development of new anti-tumor approaches to overcome the immunosuppressive environment generated by tumors.

  16. Status of vaccine research and development of vaccines for malaria.

    PubMed

    Birkett, Ashley J

    2016-06-03

    Despite recent progress in reducing deaths attributable to malaria, it continues to claim approximately 500,000 lives per year and is associated with approximately 200 million infections. New tools, including safe and effective vaccines, are needed to ensure that the gains of the last 15 years are leveraged toward achieving the ultimate goal of malaria parasite eradication. In 2015, the European Medicines Agency announced the adoption of a positive opinion for the malaria vaccine candidate most advanced in development, RTS,S/AS01, which provides modest protection against clinical malaria; in early 2016, WHO recommended large-scale pilot implementations of RTS,S in settings of moderate-to-high malaria transmission. In alignment with these advancements, the community goals and preferred product characteristics for next-generation vaccines have been updated to inform the development of vaccines that are highly efficacious in preventing clinical malaria, and those needed to accelerate parasite elimination. Next-generation vaccines, targeting all stages of the parasite lifecycle, are in early-stage development with the most advanced in Phase 2 trials. Importantly, progress is being made in the definition of feasible regulatory pathways to accelerate timelines, including for vaccines designed to interrupt transmission of parasites from humans to mosquitoes. The continued absence of financially lucrative, high-income markets to drive investment in malaria vaccine development points to continued heavy reliance on public and philanthropic funding.

  17. Leptospirosis vaccines

    PubMed Central

    Wang, Zhijun; Jin, Li; Węgrzyn, Alicja

    2007-01-01

    Leptospirosis is a serious infection disease caused by pathogenic strains of the Leptospira spirochetes, which affects not only humans but also animals. It has long been expected to find an effective vaccine to prevent leptospirosis through immunization of high risk humans or animals. Although some leptospirosis vaccines have been obtained, the vaccination is relatively unsuccessful in clinical application despite decades of research and millions of dollars spent. In this review, the recent advancements of recombinant outer membrane protein (OMP) vaccines, lipopolysaccharide (LPS) vaccines, inactivated vaccines, attenuated vaccines and DNA vaccines against leptospirosis are reviewed. A comparison of these vaccines may lead to development of new potential methods to combat leptospirosis and facilitate the leptospirosis vaccine research. Moreover, a vaccine ontology database was built for the scientists working on the leptospirosis vaccines as a starting tool. PMID:18072968

  18. Machupo Virus Expressing GPC of the Candid#1 Vaccine Strain of Junin Virus Is Highly Attenuated and Immunogenic

    PubMed Central

    Koma, Takaaki; Patterson, Michael; Huang, Cheng; Seregin, Alexey V.; Maharaj, Payal D.; Miller, Milagros; Smith, Jeanon N.; Walker, Aida G.; Hallam, Steven

    2015-01-01

    ABSTRACT Machupo virus (MACV) is the causative agent of Bolivian hemorrhagic fever. Our previous study demonstrated that a MACV strain with a single amino acid substitution (F438I) in the transmembrane domain of glycoprotein is attenuated but genetically unstable in mice. MACV is closely related to Junin virus (JUNV), the causative agent of Argentine hemorrhagic fever. Others and our group have identified the glycoprotein to be the major viral factor determining JUNV attenuation. In this study, we tested the compatibility of the glycoprotein of the Candid#1 live-attenuated vaccine strain of JUNV in MACV replication and its ability to attenuate MACV in vivo. Recombinant MACV with the Candid#1 glycoprotein (rMACV/Cd#1-GPC) exhibited growth properties similar to those of Candid#1 and was genetically stable in vitro. In a mouse model of lethal infection, rMACV/Cd#1-GPC was fully attenuated, more immunogenic than Candid#1, and fully protective against MACV infection. Therefore, the MACV strain expressing the glycoprotein of Candid#1 is safe, genetically stable, and highly protective against MACV infection in a mouse model. IMPORTANCE Currently, there are no FDA-approved vaccines and/or treatments for Bolivian hemorrhagic fever, which is a fatal human disease caused by MACV. The development of antiviral strategies to combat viral hemorrhagic fevers, including Bolivian hemorrhagic fever, is one of the top priorities of the Implementation Plan of the U.S. Department of Health and Human Services Public Health Emergency Medical Countermeasures Enterprise. Here, we demonstrate for the first time that MACV expressing glycoprotein of Candid#1 is a safe, genetically stable, highly immunogenic, and protective vaccine candidate against Bolivian hemorrhagic fever. PMID:26581982

  19. Deep Sequencing of Distinct Preparations of the Live Attenuated Varicella-Zoster Virus Vaccine Reveals a Conserved Core of Attenuating Single-Nucleotide Polymorphisms

    PubMed Central

    Yamanishi, Koichi; Gomi, Yasuyuki; Gershon, Anne A.; Breuer, Judith

    2016-01-01

    ABSTRACT The continued success of the live attenuated varicella-zoster virus vaccine in preventing varicella-zoster and herpes zoster is well documented, as are many of the mutations that contribute to the attenuation of the vOka virus for replication in skin. At least three different preparations of vOka are marketed. Here, we show using deep sequencing of seven batches of vOka vaccine (including ZostaVax, VariVax, VarilRix, and the Oka/Biken working seed) from three different manufacturers (VariVax, GSK, and Biken) that 137 single-nucleotide polymorphism (SNP) mutations are present in all vaccine batches. This includes six sites at which the vaccine allele is fixed or near fixation, which we speculate are likely to be important for attenuation. We also show that despite differences in the vaccine populations between preparations, batch-to-batch variation is minimal, as is the number and frequency of mutations unique to individual batches. This suggests that the vaccine manufacturing processes are not introducing new mutations and that, notwithstanding the mixture of variants present, VZV live vaccines are extremely stable. IMPORTANCE The continued success of vaccinations to prevent chickenpox and shingles, combined with the extremely low incidence of adverse reactions, indicates the quality of these vaccines. The vaccine itself is comprised of a heterogeneous live attenuated virus population and thus requires deep-sequencing technologies to explore the differences and similarities in the virus populations between different preparations and batches of the vaccines. Our data demonstrate minimal variation between batches, an important safety feature, and provide new insights into the extent of the mutations present in this attenuated virus. PMID:27440875

  20. A Brucella melitensis M5-90 wboA deletion strain is attenuated and enhances vaccine efficacy.

    PubMed

    Li, Zhi-Qiang; Shi, Jing-Xue; Fu, Wen-Dong; Zhang, Yu; Zhang, Jing; Wang, Zhen; Li, Tian-Sen; Chen, Chuang-Fu; Guo, Fei; Zhang, Hui

    2015-08-01

    Brucella spp. are Gram-negative intracellular pathogens of both humans and animals that cause great economic burdens in developing countries. Live attenuated vaccines are the most efficient means for the prevention and control of animal Brucellosis. However, Brucella vaccines (strain M5-90 and others) have several drawbacks and do not allow serological differentiation between vaccinated and infected animals. A wboA mutant was derived from Brucella melitensis (B. melitensis) vaccine strain M5-90 and tested for virulence and protective efficiency. T-cell responses (CD4(+), CD8(+)), levels of immunoglobulin G (IgG), and cytokine production were observed. WboA was also assessed as a diagnostic marker for Brucellosis. B. melitensis strain M5-90ΔwboA exhibited reduced survival in murine macrophages (RAW 264.7) and BALB/c mice and induced protective immunity in mice comparable to that from the parental strain M5-90. In mice, the wboA mutant elicited an anti-Brucella-specific IgG response and induced the secretion of gamma interferon (IFN-γ) and interleukin-2 (IL-2). In sheep, M5-90ΔwboA immunization induced the secretion of IFN-γ, and serum samples from sheep inoculated with M5-90ΔwboA were negative by Bengal Plate Test (RBPT) and Standard Tube Agglutination Test (STAT). In mice, probes against WboA antigen allowed for serological differentiation between natural infection and vaccination. The M5-90ΔwboA mutant is a potential attenuated live vaccine candidate against virulent B. melitensis 16M infection. It will be further evaluated in livestock.

  1. Room Temperature Stabilization of Oral, Live Attenuated Salmonella enterica serovar Typhi-Vectored Vaccines

    PubMed Central

    Ohtake, Satoshi; Martin, Russell; Saxena, Atul; Pham, Binh; Chiueh, Gary; Osorio, Manuel; Kopecko, Dennis; Xu, DeQi; Lechuga-Ballesteros, David; Truong-Le, Vu

    2011-01-01

    Foam drying, a modified freeze drying process, was utilized to produce a heat-stable, live attenuated Salmonella Typhi ‘Ty21a’ bacterial vaccine. Ty21a vaccine was formulated with pharmaceutically approved stabilizers, including sugars, plasticizers, amino acids, and proteins. Growth media and harvesting conditions of the bacteria were also studied to enhance resistance to desiccation stress encountered during processing as well as subsequent storage at elevated temperatures. The optimized Ty21a vaccine, formulated with trehalose, methionine, and gelatin, demonstrated stability for approximately 12 weeks at 37°C (i.e., time required for the vaccine to decrease in potency by 1log10 CFU) and no loss in titer at 4 and 25°C following storage for the same duration. Furthermore, the foam dried Ty21a elicited a similar immunogenic response in mice as well as protection in challenge studies compared to Vivotif™, the commercial Ty21a vaccine. The enhanced heat stability of the Ty21a oral vaccine, or Ty21a derivatives expressing foreign antigens (e.g. anthrax), could mitigate risks of vaccine potency loss during long term storage, shipping, delivery to geographical areas with warmer climates or during emergency distribution following a bioterrorist attack. Because the foam drying process is conducted using conventional freeze dryers and can be readily implemented at any freeze drying manufacturing facility, this technology appears ready and appropriate for large scale processing of foam dried vaccines. PMID:21300096

  2. Inactivated and live, attenuated influenza vaccines protect mice against influenza: Streptococcus pyogenes super-infections.

    PubMed

    Chaussee, Michael S; Sandbulte, Heather R; Schuneman, Margaret J; Depaula, Frank P; Addengast, Leslie A; Schlenker, Evelyn H; Huber, Victor C

    2011-05-12

    Mortality associated with influenza virus super-infections is frequently due to secondary bacterial complications. To date, super-infections with Streptococcus pyogenes have been studied less extensively than those associated with Streptococcus pneumoniae. This is significant because a vaccine for S. pyogenes is not clinically available, leaving vaccination against influenza virus as our only means for preventing these super-infections. In this study, we directly compared immunity induced by two types of influenza vaccine, either inactivated influenza virus (IIV) or live, attenuated influenza virus (LAIV), for the ability to prevent super-infections. Our data demonstrate that both IIV and LAIV vaccines induce similar levels of serum antibodies, and that LAIV alone induces IgA expression at mucosal surfaces. Upon super-infection, both vaccines have the ability to limit the induction of pro-inflammatory cytokines within the lung, including IFN-γ which has been shown to contribute to mortality in previous models of super-infection. Limiting expression of these pro-inflammatory cytokines within the lungs subsequently limits recruitment of macrophages and neutrophils to pulmonary surfaces, and ultimately protects both IIV- and LAIV-vaccinated mice from mortality. Despite their overall survival, both IIV- and LAIV-vaccinated mice demonstrated levels of bacteria within the lung tissue that are similar to those seen in unvaccinated mice. Thus, influenza virus:bacteria super-infections can be limited by vaccine-induced immunity against influenza virus, but the ability to prevent morbidity is not complete.

  3. Biosafety considerations for attenuated measles virus vectors used in virotherapy and vaccination

    PubMed Central

    Baldo, Aline; Galanis, Evanthia; Tangy, Frédéric; Herman, Philippe

    2016-01-01

    ABSTRACT Attenuated measles virus (MV) is one of the most effective and safe vaccines available, making it attractive candidate vector to prevent infectious diseases. Attenuated MV have acquired the ability to use the complement regulator CD46 as a major receptor to mediate virus entry and intercellular fusion. Therefore, attenuated MV strains preferentially infect and destroy a wide variety of cancer cells making them also attractive oncolytic vectors. The use of recombinant MV vector has to comply with various regulatory requirements, particularly relating to the assessment of potential risks for human health and the environment. The present article highlights the main characteristics of MV and recombinant MV vectors used for vaccination and virotherapy and discusses these features from a biosafety point of view. PMID:26631840

  4. Extended Preclinical Safety, Efficacy and Stability Testing of a Live-attenuated Chikungunya Vaccine Candidate

    PubMed Central

    Plante, Kenneth S; Rossi, Shannan L.; Bergren, Nicholas A.; Seymour, Robert L.; Weaver, Scott C.

    2015-01-01

    We recently described a new, live-attenuated vaccine candidate for chikungunya (CHIK) fever, CHIKV/IRES. This vaccine was shown to be well attenuated, immunogenic and efficacious in protecting against CHIK virus (CHIKV) challenge of mice and nonhuman primates. To further evaluate its preclinical safety, we compared CHIKV/IRES distribution and viral loads in interferon-α/β receptor-incompetent A129 mice to another CHIK vaccine candidate, 181/clone25, which proved highly immunogenic but mildly reactive in human Phase I/II clinical trials. Compared to wild-type CHIK virus, (wt-CHIKV), both vaccines generated lower viral loads in a wide variety of tissues and organs, including the brain and leg muscle, but CHIKV/IRES exhibited marked restrictions in dissemination and viral loads compared to 181/clone25, and was never found outside the blood, spleen and muscle. Unlike wt-CHIKV, which caused disrupted splenic architecture and hepatic lesions, histopathological lesions were not observed in animals infected with either vaccine strain. To examine the stability of attenuation, both vaccines were passaged 5 times intracranially in infant A129 mice, then assessed for changes in virulence by comparing parental and passaged viruses for footpad swelling, weight stability and survival after subcutaneous infection. Whereas strain 181/clone25 p5 underwent a significant increase in virulence as measured by weight loss (from <10% to >30%) and mortality (from 0 to 100%), CHIKV/IRES underwent no detectible change in any measure of virulence (no significant weight loss and no mortality). These data indicate greater nonclinical safety of the CHIKV/IRES vaccine candidate compared to 181/clone25, further supporting its eligibility for human testing. PMID:26340754

  5. Live attenuated Salmonella enterica serovar Choleraesuis vaccine vector displaying regulated delayed attenuation and regulated delayed antigen synthesis to confer protection against Streptococcus suis in mice.

    PubMed

    Ji, Zhenying; Shang, Jing; Li, Yuan; Wang, Shifeng; Shi, Huoying

    2015-09-11

    Salmonella enterica serotype Choleraesuis (S. Choleraesuis) and Streptococcus suis (S. suis) are important swine pathogens. Development of a safe and effective attenuated S. Choleraesuis vaccine vector would open a new window to prevent and control pig diseases. To achieve this goal, the mannose and arabinose regulated delayed attenuated systems (RDAS), Δpmi and ΔPcrp::TT araC PBADcrp, were introduced into the wild type S. Choleraesuis strain C78-3. We also introduced ΔrelA::araC PBADlacI TT to achieve regulated delayed antigen synthesis and ΔasdA to constitute a balanced-lethal plasmid system. The safety and immunogenicity of the resulted RDAS S. Choleraesuis strain rSC0011 carrying 6-phosphogluconate dehydrogenase (6-PGD) of S. suis serotype 2 (SS2) were evaluated in vitro and in vivo. Compared with the wild type parent strain C78-3 and vaccine strain C500, a live attenuated S. Choleraesuis vaccine licensed for piglet in China, the results showed that the survival curves of the vaccine strain rSC0011 were similar to those of strains C78-3 and C500 at the early stage of infection, but lower than those of C78-3 and higher than those of C500 at the later stage in both porcine alveolar macrophages and peripheral porcine monocytes. The LD50 of the RDAS strains rSC0011 by oral route in mice was close to that of C500 and 10,000-fold higher than that of C78-3. Similar results were achieved by intraperitoneal (i.p.) route, suggesting that the RDAS strains rSC0011 achieved similar attenuation as C500. However, the RDAS strain rSC0011 was superior to C500 in colonization of Peyer's patches. Adult mice orally immunized with strain rSC0011 carrying a plasmid expression 6-phosphogluconate dehydrogenase (6-PGD) gene from SS2 developed strong immune responses against 6-PGD and Salmonella antigens, and conferred high protection against i.p. challenge with SS2.

  6. Evaluation of two live attenuated cold-adapted H5N1 influenza virus vaccines in healthy adults

    PubMed Central

    Karron, Ruth A.; Talaat, Kawsar; Luke, Catherine; Callahan, Karen; Thumar, Bhagvanji; DiLorenzo, Susan; McAuliffe, Josephine; Schappell, Elizabeth; Suguitan, Amorsolo; Mills, Kimberly; Chen, Grace; Lamirande, Elaine; Coelingh, Kathleen; Jin, Hong; Murphy, Brian R.; Kemble, George; Subbarao, Kanta

    2016-01-01

    Background Development of live attenuated influenza vaccines (LAIV) against avian viruses with pandemic potential is an important public health strategy. Methods and Findings We performed open-label trials to evaluate the safety, infectivity, and immunogenicity of H5N1 VN 2004 AA ca and H5N1 HK 2003 AA ca. Each of these vaccines contains a modified H5 hemagglutinin and unmodified N1 neuraminidase from the respective wild-type (wt) parent virus and the six internal protein gene segments of the A/Ann Arbor/6/60 cold-adapted (ca) master donor virus. The H5N1 VN 2004 AA ca vaccine virus was evaluated at dosages of 106.7 TCID50 and 107.5 TCID50, and the H5N1 HK 2003 AA ca vaccine was evaluated at a dosage of 107.5 TCID50. Two doses were administered intranasally to healthy adults in isolation at 4 to 8 week intervals. Vaccine safety was assessed through daily examinations and infectivity was assessed by viral culture and by realtime reverse transcription-polymerase chain reaction testing of nasal wash (NW) specimens. Immunogenicity was assessed by measuring hemagglutination-inhibition (HI) antibodies, neutralizing antibodies, and IgG or IgA antibodies to recombinant (r)H5 VN 2004 hemagglutinin (HA) in serum or NW. Fifty-nine participants were enrolled: 21 received 106.7 TCID50 and 21 received 107.5 TCID50 of H5N1 VN 2004 AA ca and 17 received H5N1 HK 2003 AA ca. Shedding of vaccine virus was minimal, as were HI and neutralizing antibody responses. Fifty-two percent of recipients of 107.5 TCID50 of H5N1 VN 2004 AA ca developed a serum IgA response to rH5 VN 2004 HA. Conclusions The live attenuated H5N1 VN 2004 and HK 2003 AA ca vaccines bearing avian H5 HA antigens were very restricted in replication and were more attenuated than seasonal LAIV bearing human H1, H3 or B HA antigens. The H5N1 AA ca LAIV elicited serum ELISA antibody but not HI or neutralizing antibody responses in healthy adults. (ClinicalTrials.gov Identifiers: NCT00347672 and NCT00488046). PMID:19540952

  7. Ebola hemorrhagic Fever and the current state of vaccine development.

    PubMed

    Hong, Joo Eun; Hong, Kee-Jong; Choi, Woo Young; Lee, Won-Ja; Choi, Yeon Hwa; Jeong, Chung-Hyeon; Cho, Kwang-Il

    2014-12-01

    Current Ebola virus outbreak in West Africa already reached the total number of 1,323 including 729 deaths by July 31st. the fatality is around 55% in the southeastern area of Guinea, Sierra Leone, Liberia, and Nigeria. The number of patients with Ebola Hemorrhagic Fever (EHF) was continuously increasing even though the any effective therapeutics or vaccines has not been developed yet. The Ebola virus in Guinea showed 98% homology with Zaire Ebola Virus. Study of the pathogenesis of Ebola virus infection and assess of the various candidates of vaccine have been tried for a long time, especially in United States and some European countries. Even though the attenuated live vaccine and DNA vaccine containing Ebola viral genes were tested and showed efficacy in chimpanzees, those candidates still need clinical tests requiring much longer time than the preclinical development to be approved for the practical treatment. It can be expected to eradicate Ebola virus by a safe and efficient vaccine development similar to the case of smallpox virus which was extinguished from the world by the variola vaccine.

  8. Post-marketing surveillance of live-attenuated Japanese encephalitis vaccine safety in China.

    PubMed

    Wang, Yali; Dong, Duo; Cheng, Gang; Zuo, Shuyan; Liu, Dawei; Du, Xiaoxi

    2014-10-07

    Japanese encephalitis (JE) is the most severe form of viral encephalitis in Asia and no specific treatment is available. Vaccination provides an effective intervention to prevent JE. In this paper, surveillance data for adverse events following immunization (AEFI) related to SA-14-14-2 live-attenuated Japanese encephalitis vaccine (Chengdu Institute of Biological Products) was presented. This information has been routinely generated by the Chinese national surveillance system for the period 2009-2012. There were 6024 AEFI cases (estimated reported rate 96.55 per million doses). Most common symptoms of adverse events were fever, redness, induration and skin rash. There were 70 serious AEFI cases (1.12 per million doses), including 9 cases of meningoencephalitis and 4 cases of death. The post-marketing surveillance data add the evidence that the Chengdu institute live attenutated vaccine has a reasonable safety profile. The relationship between encephalitis and SA-14-14-2 vaccination should be further studied.

  9. Safety and immunogenicity of a live attenuated Japanese encephalitis chimeric virus vaccine (IMOJEV®) in children.

    PubMed

    Chokephaibulkit, K; Houillon, G; Feroldi, E; Bouckenooghe, A

    2016-01-01

    JE-CV (IMOJEV®, Sanofi Pasteur, France) is a live attenuated virus vaccine constructed by inserting coding sequences of the prM and E structural proteins of the Japanese encephalitis SA14-14-2 virus into the genome of yellow fever 17D virus. Primary immunization with JE-CV requires a single dose of the vaccine. This article reviews clinical trials of JE-CV in children aged up to 6 years conducted in countries across South-East Asia. Strong and persistent antibody responses were observed after single primary and booster doses, with 97% of children seroprotected up to five years after booster vaccination. Models of long-term antibody persistence predict a median duration of protection of approximately 30 years after a booster dose. The safety and reactogenicity profiles of JE-CV primary and booster doses are comparable to other widely used childhood vaccines.

  10. Comparative efficacy of various chemical stabilizers on the thermostability of a live-attenuated peste des petits ruminants (PPR) vaccine.

    PubMed

    Sarkar, J; Sreenivasa, B P; Singh, R P; Dhar, P; Bandyopadhyay, S K

    2003-12-01

    Thermostability of a live-attenuated peste des petits ruminants (PPR) vaccine recently developed at Indian Veterinary Research Institute was studied using conventional lyophilization conditions. A total of four stabilizers viz., lactalbumin hydrolysate-sucrose (LS), Weybridge medium (WBM), buffered gelatin-sorbitol (BUGS) and trehalose dihydrate (TD) were used to prepare the lyophilized vaccine. The study revealed that the PPR vaccine lyophilized with either LS or TD is more stable than rest of the stabilizers having an expiry period of at least 45 days (so far studied) at 4 degrees C, 15-19 days at 25 degrees C and 1-2 days at 37 degrees C. However, at a temperature of 45 degrees C, BUGS had a marginal superiority, although lasted for few hours, followed by TD and LS with respect to shelf-life, LS and TD with respect to half-life. On the basis of half-life also LS followed by TD appeared superior at a temperature of 4, 25 and 37 degrees C. Reconstitution of vaccine with distilled water or 1M MgSO(4) or 0.85% NaCl maintained the required virus titre (2.5log(10)TCID(50) per dose) up to 8h at 37 degrees C and 7h at 45 degrees C. Among the three diluents, 1M MgSO(4) appeared to be the better diluent for reconstitution of lyophilized PPR vaccine, as the loss on dilution was lowest and maintain the required virus titre for a longer period. Investigation suggests for using LS as stabilizer for lyophilization and 1M MgSO(4) as vaccine diluent for the newly developed PPR vaccine.

  11. Recent update in HIV vaccine development

    PubMed Central

    2016-01-01

    Despite the tremendous efforts to develop a successful human immunodeficiency virus (HIV) vaccine, the quest for a safe and effective HIV vaccine seems to be remarkably long and winding. Disappointing results from previous clinical trials of VaxGen's AIDSVAXgp120 vaccine and MRKAd5 HIV-1 Gag/Pol/Nef vaccine emphasize that understanding the correlates of immune protection in HIV infection is the key to solve the puzzle. The modest vaccine efficacy from RV144 trial and the successive results obtained from the correlate of risk analysis have reinvigorated the HIV vaccine research field leading to various novel strategies. This paper will review the brief history and recent advances in HIV vaccine development. PMID:26866018

  12. Developing a Successful HIV Vaccine.

    PubMed

    Gallo, Robert C

    2015-07-15

    Human immunodeficiency virus (HIV) genome integration indicates that persistent sterilizing immunity will be needed for a successful vaccine candidate. This suggests a need for broad antibodies targeting the Env protein. Immunogens targeting gp120 have been developed that block infection in monkeys and mimic the modest success of the RV144 clinical trial in that protection is short-lived following a decline in antibody-depending cell-mediated cytotoxicity-like antibodies. Attempts to induce antibody persistence have been complicated by a loss of efficacy, presumably by increasing the number of HIV-target cells. The key seems to be achieving an immune balance.

  13. Status of vaccine research and development of vaccines for tuberculosis.

    PubMed

    Evans, Thomas G; Schrager, Lew; Thole, Jelle

    2016-06-03

    TB is now the single pathogen that causes the greatest mortality in the world, at over 1.6 million deaths each year. The widely used the 90 year old BCG vaccine appears to have minimal impact on the worldwide incidence despite some efficacy in infants. Novel vaccine development has accelerated in the past 15 years, with 15 candidates entering human trials; two vaccines are now in large-scale efficacy studies. Modeling by three groups has consistently shown that mass vaccination that includes activity in the latently infected population, especially adolescents and young adults, will likely have the largest impact on new disease transmission. At present the field requires better validated animal models, better understanding of a correlate of immunity, new cost-effective approaches to Proof of Concept trials, and increased appreciation by the public health and scientific community for the size of the problem and the need for a vaccine. Such a vaccine is likely to also play a role in the era of increasing antibiotic resistance. Ongoing efforts and studies are working to implement these needs over the next 5 years, which will lead to an understanding that will increase the likelihood of a successful TB vaccine.

  14. The live attenuated dengue vaccine TV003 elicits complete protection against dengue in a human challenge model.

    PubMed

    Kirkpatrick, Beth D; Whitehead, Stephen S; Pierce, Kristen K; Tibery, Cecilia M; Grier, Palmtama L; Hynes, Noreen A; Larsson, Catherine J; Sabundayo, Beulah P; Talaat, Kawsar R; Janiak, Anna; Carmolli, Marya P; Luke, Catherine J; Diehl, Sean A; Durbin, Anna P

    2016-03-16

    A dengue human challenge model can be an important tool to identify candidate dengue vaccines that should be further evaluated in large efficacy trials in endemic areas. Dengue is responsible for about 390 million infections annually. Protective efficacy results for the most advanced dengue vaccine candidate (CYD) were disappointing despite its ability to induce neutralizing antibodies against all four dengue virus (DENV) serotypes. TV003 is a live attenuated tetravalent DENV vaccine currently in phase 2 evaluation. To better assess the protective efficacy of TV003, a randomized double-blind, placebo-controlled trial in which recipients of TV003 or placebo were challenged 6 months later with a DENV-2 strain, rDEN2Δ30, was conducted. The primary endpoint of the trial was protection against dengue infection, defined as rDEN2Δ30 viremia. Secondary endpoints were protection against rash and neutropenia. All 21 recipients of TV003 who were challenged with rDEN2Δ30 were protected from infection with rDEN2Δ30. None developed viremia, rash, or neutropenia after challenge. In contrast, 100% of the 20 placebo recipients who were challenged with rDEN2Δ30 developed viremia, 80% developed rash, and 20% developed neutropenia. TV003 induced complete protection against challenge with rDEN2Δ30 administered 6 months after vaccination. TV003 will be further evaluated in dengue-endemic areas. The controlled dengue human challenge model can accelerate vaccine development by evaluating the protection afforded by the vaccine, thereby eliminating poor candidates from further consideration before the initiation of large efficacy trials.

  15. An open‐label phase I trial of a live attenuated H2N2 influenza virus vaccine in healthy adults

    PubMed Central

    Talaat, Kawsar R.; Karron, Ruth A.; Liang, Philana H.; McMahon, Bridget A.; Luke, Catherine J.; Thumar, Bhagvanji; Chen, Grace L.; Min, Ji‐Young; Lamirande, Elaine W.; Jin, Hong; Coelingh, Kathy L.; Kemble, George W.; Subbarao, Kanta

    2012-01-01

    Please cite this paper as: Talaat et al. (2012) An open‐label phase I trial of a live attenuated H2N2 influenza virus vaccine in healthy adults. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00350.x. Background  Live attenuated influenza vaccines (LAIV) against a variety of strains of pandemic potential are being developed and tested. We describe the results of an open‐label phase I trial of a live attenuated H2N2 virus vaccine. Objectives  To evaluate the safety, infectivity, and immunogenicity of a live attenuated H2N2 influenza virus vaccine. Participants/methods  The A/Ann Arbor/6/60 (H2N2) virus used in this study is the attenuated, cold‐adapted, temperature‐sensitive strain that provides the genetic backbone of seasonal LAIV (MedImmune). We evaluated the safety, infectivity, and immunogenicity of two doses of 107 TCID50 of this vaccine administered by nasal spray 4 weeks apart to normal healthy seronegative adults. Results  Twenty‐one participants received a first dose of the vaccine; 18 participants received a second dose. No serious adverse events occurred during the trial. The most common adverse events after vaccination were headache and musculoskeletal pain. The vaccine was restricted in replication: 24% and 17% had virus detectable by culture or rRT‐PCR after the first and second dose, respectively. Antibody responses to the vaccine were also restricted: 24% of participants developed an antibody response as measured by either hemagglutination‐inhibition assay (10%), or ELISA for H2 HA‐specific serum IgG (24%) or IgA (16%) after either one or two doses. None of the participants had a neutralizing antibody response. Vaccine‐specific IgG‐secreting cells as measured by enzyme‐linked immunospot increased from a mean of 0·5 to 2·0/106 peripheral blood mononuclear cells (PBMCs); vaccine‐specific IgA‐secreting cells increased from 0·1 to 0·5/106 PBMCs. Conclusions  The live attenuated H2N2

  16. Development of Mucosal Vaccines Based on Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

    Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

  17. Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae

    SciTech Connect

    Dalton, J.P.; Strand, M.

    1987-10-01

    We compared the humoral immune response of mice protected against Schistosoma mansoni by vaccination with radiation-attenuated cercariae to that of patently infected mice, and we identified antigens that elicit a greater, or unique, immune response in the vaccinated mice. These comparisons were based upon radioimmunoprecipitations and immunodepletion of (/sup 35/S)methionine-labeled schistosomular and adult worm polypeptides, followed by one- and two-dimensional polyacrylamide gel analyses. The humoral responses of patently infected mice and of mice vaccinated once were remarkably similar and were directed against schistosome glycoproteins ranging in molecular size from greater than 300 to less than 10 kDa. Exposing mice to a second vaccination resulted in a marked change in the immune response, to one predominantly directed toward high molecular size glycoproteins. Sequential immunodepletion techniques identified five schistosomular and seven adult worm antigens that showed a greater or unique immunogenicity in vaccinated mice as compared with patently infected mice. These adult worm antigens were purified by preparative sequential immunoaffinity chromatography and used to prepare a polyclonal antiserum, anti-irradiated vaccine. This antiserum bound to the surface of live newly transformed and lung-stage schistosomula, as assessed by immunofluorescence assays, and was reactive with a number of /sup 125/I-labeled schistosomular surface polypeptides, including a doublet of 150 kDa that was also recognized by sera of vaccinated mice but not by sera of patently infected mice.

  18. Vaccination with Bivalent DNA Vaccine of α1-Giardin and CWP2 Delivered by Attenuated Salmonella typhimurium Reduces Trophozoites and Cysts in the Feces of Mice Infected with Giardia lamblia

    PubMed Central

    Feng, Xian-Min; Zheng, Wen-Yu; Zhang, Hong-Mei; Shi, Wen-Yan; Li, Yao; Cui, Bai-Ji; Wang, Hui-Yan

    2016-01-01

    Background Giardia lamblia is one of the most common infectious protozoans in human that may cause diarrhea in travelers. Searching for antigens that induced effectively protective immunity has become a key point in the development of vaccine against giardiasis. Methodology/Principal Findings Mice vaccinated with G. lamblia trophozozite-specific α1-giardin DNA vaccine delivered orally by attenuated Salmonella typhimurium SL7027 elicited 74.2% trophozoite reduction, but only 28% reduction in cyst shedding compared with PBS buffer control. Oral vaccination with Salmonella-delivered cyst-specific CWP2 DNA produced 89% reduction in cysts shedding in feces of vaccinated mice. Significantly, the mice vaccinated with Salmonella-delivered bivalent α1-giardin and CWP2 DNA vaccines produced significant reduction in both trophozoite (79%) and cyst (93%) in feces of vaccinated mice. This parasite reduction is associated with the strong local mucosal IgA secretion and the IgG2a-dominant systemic immune responses in vaccinated mice. Conclusions The results demonstrate that bivalent vaccines targeting α1-giardin and CWP2 can protect mice against the colonization of Giardia trophozoite and block the transformation of cyst in host at the same time, and can be used to prevent Giardia infection and block the transmission of giardiasis. PMID:27332547

  19. Experience with live attenuated varicella vaccine (Oka strain) in healthy Japanese subjects; 10-year survey at pediatric clinic.

    PubMed

    Ozaki, T; Nishimura, N; Kajita, Y

    2000-05-08

    Live attenuated varicella vaccine (Oka strain, Biken Institute, Osaka, Japan) was administered to 973 healthy individuals over a 10-year period (1987-1997) at the pediatric clinic of Showa Hospital in Japan. We evaluated the relevant serological and clinical data, which were collected by questionnaire. Seroconversion by the immune adherence hemagglutination method was documented in 94% (805/860) of the initially seronegative subjects. Of the initially seropositive subjects, 56% (63/113) showed enhancement of antibody after vaccination. Reactions to the vaccine were generally insignificant, except for a rash at the injection site, seen in the first 3 days post-administration in 17% (41/241) of the recently vaccinated subjects. In March 1998, we conducted a survey of 559 of the initially seronegative subjects who had received the vaccine 0.6-10. 8 (mean 5.4) years earlier. Of these subjects, 21% (119/559) contracted breakthrough varicella. However, their symptoms were milder than those caused by natural varicella seen in unvaccinated children. Seroconversion was demonstrated in 92% (109/119) of these cases. The incidence of breakthrough disease decreased with a rise in postvaccination antibody titer to >==32. Four of the subjects (0.7% of 559) developed herpes zoster following vaccination, two of whom had earlier exhibited breakthrough varicella. Lesions in one case of zoster, without breakthrough varicella, appeared on the cervical dermatome at the injection site. The vaccine was safe and effective. However, there was a relatively high incidence of rash at the injection site with certain lot numbers used in recent years which warrants investigation.

  20. Public health impact and cost-effectiveness of intranasal live attenuated influenza vaccination of children in Germany.

    PubMed

    Damm, Oliver; Eichner, Martin; Rose, Markus Andreas; Knuf, Markus; Wutzler, Peter; Liese, Johannes Günter; Krüger, Hagen; Greiner, Wolfgang

    2015-06-01

    In 2011, intranasally administered live attenuated influenza vaccine (LAIV) was approved in the EU for prophylaxis of seasonal influenza in 2-17-year-old children. Our objective was to estimate the potential epidemiological impact and cost-effectiveness of an LAIV-based extension of the influenza vaccination programme to healthy children in Germany. An age-structured dynamic model of influenza transmission was developed and combined with a decision-tree to evaluate different vaccination strategies in the German health care system. Model inputs were based on published literature or were derived by expert consulting using the Delphi technique. Unit costs were drawn from German sources. Under base-case assumptions, annual routine vaccination of children aged 2-17 years with LAIV assuming an uptake of 50% would prevent, across all ages, 16 million cases of symptomatic influenza, over 600,000 cases of acute otitis media, nearly 130,000 cases of community-acquired pneumonia, nearly 1.7 million prescriptions of antibiotics and over 165,000 hospitalisations over 10 years. The discounted incremental cost-effectiveness ratio was 1,228 per quality-adjusted life year gained from a broad third-party payer perspective (including reimbursed direct costs and specific transfer payments), when compared with the current strategy of vaccinating primarily risk groups with the conventional trivalent inactivated vaccine. Inclusion of patient co-payments and indirect costs in terms of productivity losses resulted in discounted 10-year cost savings of 3.4 billion. In conclusion, adopting universal influenza immunisation of healthy children and adolescents would lead to a substantial reduction in influenza-associated disease at a reasonable cost to the German statutory health insurance system. On the basis of the epidemiological and health economic simulation results, a recommendation of introducing annual routine influenza vaccination of children 2-17 years of age might be

  1. Cross-protection against Salmonella Typhimurium infection conferred by a live attenuated Salmonella Enteritidis vaccine.

    PubMed

    Nandre, Rahul M; Lee, Dajeong; Lee, John Hwa

    2015-01-01

    In this study, a genetically engineered live attenuated Salmonella Enteritidis (SE) vaccine was evaluated for its ability to protect against Salmonella Typhimurium (ST) infection in chickens. The birds were orally primed with the vaccine on the 1st day of life and given an oral booster at 5 wk of age. Control birds were orally inoculated with phosphate-buffered saline. Both groups of birds were orally challenged with a virulent ST strain at 9 wk of age. Compared with the control chickens, the vaccinated chickens had significantly higher levels of systemic IgG and mucosal IgA against specific ST antigens and a significantly greater lymphoproliferative response to ST antigens. The excretion of ST into the feces was significantly lower in the vaccinated group than in the control group on days 9 and 13 d after challenge. In addition, the vaccinated group had significantly fewer pronounced gross lesions in the liver and spleen and lower bacterial counts in the internal organs than the control group after challenge. These data indicate that genetically engineered live attenuated SE may induce humoral and cellular immune responses against ST antigens and may confer protection against virulent ST challenge.

  2. Cross-protection against Salmonella Typhimurium infection conferred by a live attenuated Salmonella Enteritidis vaccine

    PubMed Central

    Nandre, Rahul M.; Lee, Dajeong; Lee, John Hwa

    2015-01-01

    In this study, a genetically engineered live attenuated Salmonella Enteritidis (SE) vaccine was evaluated for its ability to protect against Salmonella Typhimurium (ST) infection in chickens. The birds were orally primed with the vaccine on the 1st day of life and given an oral booster at 5 wk of age. Control birds were orally inoculated with phosphate-buffered saline. Both groups of birds were orally challenged with a virulent ST strain at 9 wk of age. Compared with the control chickens, the vaccinated chickens had significantly higher levels of systemic IgG and mucosal IgA against specific ST antigens and a significantly greater lymphoproliferative response to ST antigens. The excretion of ST into the feces was significantly lower in the vaccinated group than in the control group on days 9 and 13 d after challenge. In addition, the vaccinated group had significantly fewer pronounced gross lesions in the liver and spleen and lower bacterial counts in the internal organs than the control group after challenge. These data indicate that genetically engineered live attenuated SE may induce humoral and cellular immune responses against ST antigens and may confer protection against virulent ST challenge. PMID:25673904

  3. Human transcriptome response to immunization with live-attenuated Venezuelan equine encephalitis virus vaccine (TC-83): Analysis of whole blood

    PubMed Central

    Erwin-Cohen, Rebecca A.; Porter, Aimee I.; Pittman, Phillip R.; Rossi, Cynthia A.; DaSilva, Luis

    2017-01-01

    ABSTRACT Venezuelan equine encephalitis virus (VEEV) is an important human and animal alphavirus pathogen transmitted by mosquitoes. The virus is endemic in Central and South America, but has also caused equine outbreaks in southwestern areas of the United States. In an effort to better understand the molecular mechanisms of the development of immunity to this important pathogen, we performed transcriptional analysis from whole, unfractionated human blood of patients who had been immunized with the live-attenuated vaccine strain of VEEV, TC-83. We compared changes in the transcriptome between naïve individuals who were mock vaccinated with saline to responses of individuals who received TC-83. Significant transcriptional changes were noted at days 2, 7, and 14 following vaccination. The top canonical pathways revealed at early and intermediate time points (days 2 and 7) included the involvement of the classic interferon response, interferon-response factors, activation of pattern recognition receptors, and engagement of the inflammasome. By day 14, the top canonical pathways included oxidative phosphorylation, the protein ubiquitination pathway, natural killer cell signaling, and B-cell development. Biomarkers were identified that differentiate between vaccinees and control subjects, at early, intermediate, and late stages of the development of immunity as well as markers which were common to all 3 stages following vaccination but distinct from the sham-vaccinated control subjects. The study represents a novel examination of molecular processes that lead to the development of immunity against VEEV in humans and which may be of value as diagnostic targets, to enhance modern vaccine design, or molecular correlates of protection. PMID:27870591

  4. Status of vaccine research and development of vaccines for leishmaniasis.

    PubMed

    Gillespie, Portia M; Beaumier, Coreen M; Strych, Ulrich; Hayward, Tara; Hotez, Peter J; Bottazzi, Maria Elena

    2016-06-03

    A number of leishmaniasis vaccine candidates are at various stages of pre-clinical and clinical development. Leishmaniasis is a vector-borne neglected tropical disease (NTD) caused by a protozoan parasite of the genus Leishmania and transmitted to humans by the bite of a sand fly. Visceral leishmaniasis (VL, kala-azar) is a high mortality NTD found mostly in South Asia and East Africa, while cutaneous leishmaniasis (CL) is a disfiguring NTD highly endemic in the Middle East, Central Asia, North Africa, and the Americas. Estimates attribute 50,000 annual deaths and 3.3 million disability-adjusted life years to leishmaniasis. There are only a few approved drug treatments, no prophylactic drug and no vaccine. Ideally, an effective vaccine against leishmaniasis will elicit long-lasting immunity and protect broadly against VL and CL. Vaccines such as Leish-F1, F2 and F3, developed at IDRI and designed based on selected Leishmania antigen epitopes, have been in clinical trials. Other groups, including the Sabin Vaccine Institute in collaboration with the National Institutes of Health are investigating recombinant Leishmania antigens in combination with selected sand fly salivary gland antigens in order to augment host immunity. To date, both VL and CL vaccines have been shown to be cost-effective in economic modeling studies.

  5. Enhancement of the safety of live influenza vaccine by attenuating mutations from cold-adapted hemagglutinin

    SciTech Connect

    Lee, Yoon Jae; Jang, Yo Han; Kim, Paul; Lee, Yun Ha; Lee, Young Jae; Byun, Young Ho; Lee, Kwang-Hee; Kim, Kyusik; Seong, Baik Lin

    2016-04-15

    In our previous study, X-31ca-based H5N1 LAIVs, in particular, became more virulent in mice than the X-31ca MDV, possibly by the introduction of the surface antigens of highly pathogenic H5N1 influenza virus, implying that additional attenuation is needed in this cases to increase the safety level of the vaccine. In this report we suggest an approach to further increase the safety of LAIV through additional cold-adapted mutations in the hemagglutinin. The cold-adaptation of X-31 virus resulted in four amino acid mutations in the HA. We generated a panel of 7:1 reassortant viruses each carrying the hemagglutinins with individual single amino acid mutations. We examined their phenotypes and found a major attenuating mutation, N81K. This attenuation marker conferred additional temperature-sensitive and attenuation phenotype to the LAIV. Our data indicate that the cold-adapted mutation in the HA confers additional attenuation to the LAIV strain, without compromising its productivity and immune response. - Highlights: • Cold-adaptation process induced four amino acid mutations in the HA of X-31 virus. • The four mutations in the HA also contributed to attenuation of the X-31ca virus • N81K mutation was the most significant marker for the attenuation of X-31ca virus. • Introduction of N81K mutation into H3N2 LAIV further attenuated the vaccine. • This approach provides a useful guideline for enhancing the safety of the LAIVs.

  6. Systematic annotation and analysis of “virmugens” - virulence factors whose mutants can be used as live attenuated vaccines

    PubMed Central

    Racz, Rebecca; Chung, Monica; Xiang, Zuoshuang; He, Yongqun

    2012-01-01

    Live attenuated vaccines are usually generated by mutation of genes encoding virulence factors. “Virmugen” is coined here to represent a gene that encodes for a virulent factor of a pathogen and has been proven feasible in animal models to make a live attenuated vaccine by knocking out this gene. Not all virulence factors are virmugens. VirmugenDB is a web-based virmugen database (http://www.violinet.org/virmugendb). Currently, VirmugenDB includes 225 virmugens that have been verified to be valuable for vaccine development against 57 bacterial, viral, and protozoan pathogens. Bioinformatics analysis has revealed significant patterns in virmugens. For example, 10 Gram-negative and one Gram-positive bacterial aroA genes are virmugens. A sequence analysis has revealed at least 50% of identities in the protein sequences of the 10 Gram-negative bacterial aroA virmugens. As a pathogen case study, Brucella virmugens were analyzed. Out of 15 verified Brucella virmugens, six are related to carbohydrate or nucleotide transport and metabolism, and two involving cell membrane biogenesis. In addition, 54 virmugens from 24 viruses and 12 virmugens from 4 parasites are also stored in VirmugenDB. Virmugens tend to involve metabolism of nutrients (e.g., amino acids, carbohydrates, and nucleotides) and cell membrane formation. Host genes whose expressions were regulated by virmugen mutation vaccines or wild type virulent pathogens have also been annotated and systematically compared. The bioinformatics annotation and analysis of virmugens helps elucidate enriched virmugen profiles and the mechanisms of protective immunity, and further supports rational vaccine design. PMID:23219434

  7. Development of Mycoplasma hyopneumoniae Recombinant Vaccines.

    PubMed

    Marchioro, Silvana Beutinger; Simionatto, Simone; Dellagostin, Odir

    2016-01-01

    Mycoplasma hyopneumoniae is the etiological agent of swine enzootic pneumonia (EP), a disease that affects swine production worldwide. Vaccination is the most cost-effective strategy for the control and prevention of the disease. Research using genome-based approach has the potential to elucidate the biology and pathogenesis of M. hyopneumoniae and contribute to the development of more effective vaccines. Here, we describe the protocol for developing M. hyopneumoniae recombinant vaccines using reverse vaccinology approaches.

  8. Dengue human infection models to advance dengue vaccine development.

    PubMed

    Larsen, Christian P; Whitehead, Stephen S; Durbin, Anna P

    2015-12-10

    Dengue viruses (DENV) currently infect approximately 400 million people each year causing millions to seek care and overwhelming the health care infrastructure in endemic areas. Vaccines to prevent dengue and therapeutics to treat dengue are not currently available. The efficacy of the most advanced candidate vaccine against symptomatic dengue in general and DENV-2 in particular was much lower than expected, despite the ability of the vaccine to induce neutralizing antibody against all four DENV serotypes. Because seroconversion to the DENV serotypes following vaccination was thought to be indicative of induced protection, these results have made it more difficult to assess which candidate vaccines should or should not be evaluated in large studies in endemic areas. A dengue human infection model (DHIM) could be extremely valuable to down-select candidate vaccines or therapeutics prior to engaging in efficacy trials in endemic areas. Two DHIM have been developed to assess the efficacy of live attenuated tetravalent (LATV) dengue vaccines. The first model, developed by the Laboratory of Infectious Diseases at the U. S. National Institutes of Health, utilizes a modified DENV-2 strain DEN2Δ30. This virus was derived from the DENV-2 Tonga/74 that caused only very mild clinical infection during the outbreak from which it was recovered. DEN2Δ30 induced viremia in 100%, rash in 80%, and neutropenia in 27% of the 30 subjects to whom it was given. The Walter Reed Army Institute of Research (WRAIR) is developing a DHIM the goal of which is to identify DENV that cause symptomatic dengue fever. WRAIR has evaluated seven viruses and has identified two that meet dengue fever criteria. Both of these models may be very useful in the evaluation and down-selection of candidate dengue vaccines and therapeutics.

  9. WHO informal consultation on quality, safety and efficacy specifications for live attenuated rotavirus vaccines Mexico City, Mexico, 8-9 February 2005.

    PubMed

    Wood, David

    2005-12-01

    Rotavirus vaccines are at an advanced stage of development but there are as yet no WHO recommendations on production and quality control to provide regulatory guidance. A meeting of experts was convened by WHO and PAHO/AMRO to review the scientific basis for production and quality control of rotavirus vaccines, and to discuss specific measures to assure the safety and efficacy of rotavirus vaccines. The meeting was attended by 25 experts from 14 countries, drawn from academia, public health, national regulatory authorities and vaccine producers. It was agreed that existing guidance for other live virus vaccines provides a very good basis for product characterization, especially for source materials and control of production. The basis for attenuation of current vaccines or vaccine candidates is not known but, at least for the vaccines based on the Jennerian approach of using animal (bovine) rotaviruses, is likely to be multigenic. The risk of intussusception in humans is influenced by genetic background and age. Recent analyzes of large vaccine safety trials found that certain strains of vaccine virus were not associated with intussusception, although in these trials the first dose of vaccine was not administered to children over 3 months of age. Since age is a risk factor for intussusception, this may suggest that early delivery of the first dose of vaccine is desirable. However, maternal antibodies may mitigate against early delivery of the first vaccine dose. Factors which could affect vaccine efficacy or safety include strain diversity, malnutrition, other enteric infections, parasitic infection or immune suppression. It was concluded that data from clinical trials conducted in one part of the world would not necessarily be predictive of vaccine efficacy in other places. It was agreed that in nonclinical evaluations there was a need to use oral dosing for toxicity studies and, because rotavirus is non-neurovirulent, that there was no need for an animal

  10. Immune responses elicited to a live-attenuated influenza virus vaccine compared to a traditional whole-inactivated virus vaccine for pandemic H1N1in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States there are currently two influenza vaccine platforms approved for use in humans - conventional inactivated virus and live-attenuated influenza virus (LAIV). One of the major challenges for influenza vaccination is designing a platform that provides cross-protection across strains...

  11. New Approaches to HIV Vaccine Development

    PubMed Central

    Haynes, Barton F.

    2015-01-01

    Development of a safe and effective vaccine for HIV is a major global priority. However, to date, efforts to design an HIV vaccine with methods used for development of other successful viral vaccines have not succeeded due to HIV diversity, HIV integration into the host genome, and ability of HIV to consistently evade anti-viral immune responses. Recent success in isolation of potent broadly neutralizing antibodies (bnAbs), discovery of mechanisms of bnAb induction, and in discovery of atypical mechanisms of CD8 T cell killing of HIV-infected cells, have opened new avenues for strategies for HIV vaccine design. PMID:26056742

  12. Engineered alphavirus replicon vaccines based on known attenuated viral mutants show limited effects on immunogenicity.

    PubMed

    Maruggi, Giulietta; Shaw, Christine A; Otten, Gillis R; Mason, Peter W; Beard, Clayton W

    2013-12-01

    The immunogenicity of alphavirus replicon vaccines is determined by many factors including the level of antigen expression and induction of innate immune responses. Characterized attenuated alphavirus mutants contain changes to the genomic 5' UTR and mutations that result in altered non-structural protein cleavage timing leading to altered levels of antigen expression and interferon (IFN) induction. In an attempt to create more potent replicon vaccines, we engineered a panel of Venezuelan equine encephalitis-Sindbis virus chimeric replicons that contained these attenuating mutations. Modified replicons were ranked for antigen expression and IFN induction levels in cell culture and then evaluated in mice. The results of these studies showed that differences in antigen production and IFN induction in vitro did not correlate with large changes in immunogenicity in vivo. These findings indicate that the complex interactions between innate immune response and the replicon's ability to express antigen complicate rational design of more potent alphavirus replicons.

  13. In vitro analysis of virus particle subpopulations in candidate live-attenuated influenza vaccines distinguishes effective from ineffective vaccines.

    PubMed

    Marcus, Philip I; Ngunjiri, John M; Sekellick, Margaret J; Wang, Leyi; Lee, Chang-Won

    2010-11-01

    Two effective (vac+) and two ineffective (vac-) candidate live-attenuated influenza vaccines (LAIVs) derived from naturally selected genetically stable variants of A/TK/OR/71-delNS1[1-124] (H7N3) that differed only in the length and kind of amino acid residues at the C terminus of the nonstructural NS1 protein were analyzed for their content of particle subpopulations. These subpopulations included total physical particles (measured as hemagglutinating particles [HAPs]) with their subsumed biologically active particles of infectious virus (plaque-forming particles [PFPs]) and different classes of noninfectious virus, namely, interferon-inducing particles (IFPs), noninfectious cell-killing particles (niCKPs), and defective interfering particles (DIPs). The vac+ variants were distinguished from the vac- variants on the basis of their content of viral subpopulations by (i) the capacity to induce higher quantum yields of interferon (IFN), (ii) the generation of an unusual type of IFN-induction dose-response curve, (iii) the presence of IFPs that induce IFN more efficiently, (iv) reduced sensitivity to IFN action, and (v) elevated rates of PFP replication that resulted in larger plaques and higher PFP and HAP titers. These in vitro analyses provide a benchmark for the screening of candidate LAIVs and their potential as effective vaccines. Vaccine design may be improved by enhancement of attributes that are dominant in the effective (vac+) vaccines.

  14. Development of a recombinant, chimeric tetravalent dengue vaccine candidate.

    PubMed

    Osorio, Jorge E; Partidos, Charalambos D; Wallace, Derek; Stinchcomb, Dan T

    2015-12-10

    Dengue is a significant threat to public health worldwide. Currently, there are no licensed vaccines available for dengue. Takeda Vaccines Inc. is developing a live, attenuated tetravalent dengue vaccine candidate (TDV) that consists of an attenuated DENV-2 strain (TDV-2) and three chimeric viruses containing the prM and E protein genes of DENV-1, -3 and -4 expressed in the context of the attenuated TDV-2 genome backbone (TDV-1, TDV-3, and TDV-4, respectively). TDV has been shown to be immunogenic and efficacious in nonclinical animal models. In interferon-receptor deficient mice, the vaccine induces humoral neutralizing antibody responses and cellular immune responses that are sufficient to protect from lethal challenge with DENV-1, DENV-2 or DENV-4. In non-human primates, administration of TDV induces innate immune responses as well as long lasting antibody and cellular immunity. In Phase 1 clinical trials, the safety and immunogenicity of two different formulations were assessed after intradermal or subcutaneous administration to healthy, flavivirus-naïve adults. TDV administration was generally well-tolerated independent of dose and route. The vaccine induced neutralizing antibody responses to all four DENV serotypes: after a single administration of the higher formulation, 24-67%% of the subjects seroconverted to all four DENV and >80% seroconverted to three or more viruses. In addition, TDV induced CD8(+) T cell responses to the non-structural NS1, NS3 and NS5 proteins of DENV. TDV has been also shown to be generally well tolerated and immunogenic in a Phase 2 clinical trial in dengue endemic countries in adults and children as young as 18 months. Additional clinical studies are ongoing in preparation for a Phase 3 safety and efficacy study.

  15. Safety and Immunogenicity of a Live-Attenuated Junin (Argentine Hemorrhagic Fever) Vaccine in Rhesus Macaques

    DTIC Science & Technology

    1993-01-01

    virus from animals in every dose group. vetted 1-2.5 weeks after initial virus recovery. That the viruses recovered were Junin virus is certain: all...wild-type strains (LI 1.25). When vivo neutralization and virus clearance are com- we used this system to examine viruses recovered plex and multi...Fredertcktfarniand Abstract. The safety and immunogenicity of Candid #1. a live-attenuated Junin- virus vaccine, were evaluated in rhesus macaques. Candid #1 was

  16. Shigella vaccine development: prospective animal models and current status.

    PubMed

    Kim, Yeon-Jeong; Yeo, Sang-Gu; Park, Jae-Hak; Ko, Hyun-Jeong

    2013-01-01

    Shigella was first discovered in 1897 and is a major causative agent of dysenteric diarrhea. The number of affected patients has decreased globally because of improved sanitary conditions; however, Shigella still causes serious problems in many subjects, including young children and the elderly, especially in developing countries. Although antibiotics may be effective, a vaccine would be the most powerful solution to combat shigellosis because of the emergence of drug-resistant strains. However, the development of a vaccine is hampered by several problems. First, there is no suitable animal model that can replace human-based studies for the investigation of the in vivo mechanisms of Shigella vaccines. Mouse, guinea pig, rat, rabbit, and nonhuman primates could be used as models for shigellosis, but they do not represent human shigellosis and each has its own weaknesses. However, a recent murine model based on peritoneal infection with virulent S. flexneri 2a is promising. Moreover, although the inflammatory responses and mechanisms such as pathogenassociated molecular patterns and danger-associated molecular patterns have been studied, the pathology and immunology of Shigella are still not clearly defined. Despite these obstacles, many vaccine candidates have been developed, including live attenuated, killed whole cells, conjugated, and subunit vaccines. The development of Shigella vaccines also demands considerations of the cost, routes of administration, ease of storage (stability), cross-reactivity, safety, and immunogenicity. The main aim of this review is to provide a detailed introduction to the many promising vaccine candidates and animal models currently available, including the newly developed mouse model.

  17. DNA vaccines: developing new strategies against cancer.

    PubMed

    Fioretti, Daniela; Iurescia, Sandra; Fazio, Vito Michele; Rinaldi, Monica

    2010-01-01

    Due to their rapid and widespread development, DNA vaccines have entered into a variety of human clinical trials for vaccines against various diseases including cancer. Evidence that DNA vaccines are well tolerated and have an excellent safety profile proved to be of advantage as many clinical trials combines the first phase with the second, saving both time and money. It is clear from the results obtained in clinical trials that such DNA vaccines require much improvement in antigen expression and delivery methods to make them sufficiently effective in the clinic. Similarly, it is clear that additional strategies are required to activate effective immunity against poorly immunogenic tumor antigens. Engineering vaccine design for manipulating antigen presentation and processing pathways is one of the most important aspects that can be easily handled in the DNA vaccine technology. Several approaches have been investigated including DNA vaccine engineering, co-delivery of immunomodulatory molecules, safe routes of administration, prime-boost regimen and strategies to break the immunosuppressive networks mechanisms adopted by malignant cells to prevent immune cell function. Combined or single strategies to enhance the efficacy and immunogenicity of DNA vaccines are applied in completed and ongoing clinical trials, where the safety and tolerability of the DNA platform are substantiated. In this review on DNA vaccines, salient aspects on this topic going from basic research to the clinic are evaluated. Some representative DNA cancer vaccine studies are also discussed.

  18. Clinical trials with Alice strain, live, attenuated, serum inhibitor-resistant intranasal influenza A vaccine.

    PubMed

    Spencer, M J; Cherry, J D; Powell, K R; Sumaya, C V; Garakian, A J

    1975-10-01

    Two clinical trials with Alice strain intranasal influenza vaccine were performed. In study no. 1 (utilizing random selection and double-blind control), 50 subjects received a bivalent inactivated influenza vaccine intramuscularly, 99 subjects received Alice strain vaccine intranasally, and 50 subjects received a placebo intranasally. No symptomatology could be attributed to the intranasal route of immunization. Convalescent-phase geometric mean titers of hemagglutination inhibition antibody were higher after intramuscular vaccination; seroconversion occurred in 16 or 17 recipients of the Alice strain, with initial titers of less than 1:8. Clinical and virologic surveillance for 20 weeks after vaccination revealed no influenza A illnesses in participants of the study. In study no. 2, 75% of the subjects with initial nasal antibody titers of less than 1:3 developed measurable nasal antibody after receiving Alice strain vaccine.

  19. Application of radiation technology in vaccines development

    PubMed Central

    2015-01-01

    One of the earliest methods used in the manufacture of stable and safe vaccines is the use of chemical and physical treatments to produce inactivated forms of pathogens. Although these types of vaccines have been successful in eliciting specific humoral immune responses to pathogen-associated immunogens, there is a large demand for the development of fast, safe, and effective vaccine manufacturing strategies. Radiation sterilization has been used to develop a variety of vaccine types, because it can eradicate chemical contaminants and penetrate pathogens to destroy nucleic acids without damaging the pathogen surface antigens. Nevertheless, irradiated vaccines have not widely been used at an industrial level because of difficulties obtaining the necessary equipment. Recent successful clinical trials of irradiated vaccines against pathogens and tumors have led to a reevaluation of radiation technology as an alternative method to produce vaccines. In the present article, we review the challenges associated with creating irradiated vaccines and discuss potential strategies for developing vaccines using radiation technology. PMID:26273573

  20. Development of Novel Vaccines against Enterovirus-71

    PubMed Central

    Yee, Pinn Tsin Isabel; Poh, Chit Laa

    2015-01-01

    The hand, foot and mouth disease is caused by a group of Enteroviruses such as Enterovirus 71 (EV-A71) and Coxsackievirus CV-A5, CV-A8, and CV-A16. Mild symptoms of EV-A71 infection in children range from high fever, vomiting, rashes and ulcers in mouth but can produce more severe symptoms such as brainstem and cerebellar encephalitis, leading up to cardiopulmonary failure and death. The lack of vaccines and antiviral drugs against EV-A71 highlights the urgency of developing preventive and treatment agents against EV-A71 to prevent further fatalities. Research groups have developed experimental inactivated vaccines, recombinant Viral Protein 1 (VP1) vaccine and virus-like particles (VLPs). The inactivated EV-A71 vaccine is considered the safest viral vaccine, as there will be no reversion to the infectious wild type strain. The recombinant VP1 vaccine is a cost-effective immunogen, while VLPs contain an arrangement of epitopes that can elicit neutralizing antibodies against the virus. As each type of vaccine has its advantages and disadvantages, increased studies are required in the development of such vaccines, whereby high efficacy, long-lasting immunity, minimal risk to those vaccinated, safe and easy production, low cost, dispensing the need for refrigeration and convenient delivery are the major goals in their design. PMID:26729152

  1. New strategies for the development of H5N1 subtype influenza vaccines: progress and challenges.

    PubMed

    Steel, John

    2011-10-01

    The emergence and spread of highly pathogenic avian influenza (H5N1) viruses among poultry in Asia, the Middle East, and Africa have fueled concerns of a possible human pandemic, and spurred efforts towards developing vaccines against H5N1 influenza viruses, as well as improving vaccine production methods. In recent years, promising experimental reverse genetics-derived H5N1 live attenuated vaccines have been generated and characterized, including vaccines that are attenuated through temperature-sensitive mutation, modulation of the interferon antagonist protein, or disruption of the M2 protein. Live attenuated influenza virus vaccines based on each of these modalities have conferred protection against homologous and heterologous challenge in animal models of influenza virus infection. Alternative vaccine strategies that do not require the use of live virus, such as virus-like particle (VLP) and DNA-based vaccines, have also been vigorously pursued in recent years. Studies have demonstrated that influenza VLP vaccination can confer homologous and heterologous protection from lethal challenge in a mouse model of infection. There have also been improvements in the formulation and production of vaccines following concerns over the threat of H5N1 influenza viruses. The use of novel substrates for the growth of vaccine virus stocks has been intensively researched in recent years, and several candidate cell culture-based systems for vaccine amplification have emerged, including production systems based on Madin-Darby canine kidney, Vero, and PerC6 cell lines. Such systems promise increased scalability of product, and reduced reliance on embryonated chicken eggs as a growth substrate. Studies into the use of adjuvants have shown that oil-in-water-based adjuvants can improve the immunogenicity of inactivated influenza vaccines and conserve antigen in such formulations. Finally, efforts to develop more broadly cross-protective immunization strategies through the inclusion

  2. Sublingual vaccine with GroEL attenuates atherosclerosis.

    PubMed

    Hagiwara, M; Kurita-Ochiai, T; Kobayashi, R; Hashizume-Takizawa, T; Yamazaki, K; Yamamoto, M

    2014-04-01

    Autoimmune responses to heat-shock protein 60 (HSP60) contribute to the progression of atherosclerosis, whereas immunization with HSP60 may induce atheroprotective responses. We assessed the capacity of an atheroprotective vaccine that targeted a recombinant HSP60 from Porphyromonas gingivalis (rGroEL) to induce a protective mucosal immune response. Female apolipoprotein E-deficient spontaneously hyperlipidemic (Apoe(shl)) mice received sublingual delivery of rGroEL prior to P. gingivalis 381 injection. The animals were euthanized 16 weeks later. Sublingual immunization with rGroEL induced significant rGroEL-specific serum IgG responses. Antigen-specific cells isolated from spleen produced significantly high levels of IL-10 and IFN-γ after antigen re-stimulation in vitro. Flow cytometric analysis indicated that the frequencies of both IL-10(+) and IFN-γ(+) CD4(+) Foxp3(+) cells increased significantly in submandibular glands (SMG). Furthermore, sublingual immunization with rGroEL significantly reduced atherosclerosis lesion formation in the aortic sinus and decreased serum CRP, MCP-1, and ox-LDL levels. These findings suggest that sublingual immunization with rGroEL is associated with the increase of IFNγ(+) or IL-10(+) Foxp3(+) cells in SMG and a systemic humoral response, which could be an effective strategy for the prevention of naturally occurring or P. gingivalis-accelerated atherosclerosis.

  3. Correlates of Immunity to Influenza as Determined by Challenge of Children with Live, Attenuated Influenza Vaccine

    PubMed Central

    Wright, Peter F.; Hoen, Anne G.; Ilyushina, Natalia A.; Brown, Eric P.; Ackerman, Margaret E.; Wieland-Alter, Wendy; Connor, Ruth I.; Jegaskanda, Sinthujan; Rosenberg-Hasson, Yael; Haynes, Brenda C.; Luke, Catherine J.; Subbarao, Kanta; Treanor, John J.

    2016-01-01

    Background. The efficacy of live, attenuated live attenuated influenza vaccine(LAIV) and inactivated influenza vaccine(IIV) is poorly explained by either single or composite immune responses to vaccination. Protective biomarkers were therefore studied in response to LAIV or IIV followed by LAIV challenge in children. Methods. Serum and mucosal responses to LAIV or IIV were analyzed using immunologic assays to assess both quantitative and functional responses. Cytokines and chemokines were measured in nasal washes collected before vaccination, on days 2, 4, and 7 after initial LAIV, and again after LAIV challenge using a 63-multiplex Luminex panel. Results. Patterns of immunity induced by LAIV and IIV were significantly different. Serum responses induced by IIV, including hemagglutination inhibition, did not correlate with detection or quantitation of LAIV on subsequent challenge. Modalities that induced sterilizing immunity seen after LAIV challenge could not be defined by any measurements of mucosal or serum antibodies induced by the initial LAIV immunization. No single cytokine or chemokine was predictive of protection. Conclusions. The mechanism of protective immunity observed after LAIV could not be defined, and traditional measurements of immunity to IIV did not correlate with protection against an LAIV challenge. PMID:27419180

  4. Burkholderia mallei CLH001 Attenuated Vaccine Strain Is Immunogenic and Protects against Acute Respiratory Glanders

    PubMed Central

    Hatcher, Christopher L.; Mott, Tiffany M.; Muruato, Laura A.; Sbrana, Elena

    2016-01-01

    Burkholderia mallei is the causative agent of glanders, an incapacitating disease with high mortality rates in respiratory cases. Its endemicity and ineffective treatment options emphasize its public health threat and highlight the need for a vaccine. Live attenuated vaccines are considered the most viable vaccine strategy for Burkholderia, but single-gene-deletion mutants have not provided complete protection. In this study, we constructed the select-agent-excluded B. mallei ΔtonB Δhcp1 (CLH001) vaccine strain and investigated its ability to protect against acute respiratory glanders. Here we show that CLH001 is attenuated, safe, and effective at protecting against lethal B. mallei challenge. Intranasal administration of CLH001 to BALB/c and NOD SCID gamma (NSG) mice resulted in complete survival without detectable colonization or abnormal organ histopathology. Additionally, BALB/c mice intranasally immunized with CLH001 in a prime/boost regimen were fully protected against lethal challenge with the B. mallei lux (CSM001) wild-type strain. PMID:27271739

  5. Effects of Adaptation of Infectious Bronchitis Virus Arkansas Attenuated Vaccine to Embryonic Kidney Cells.

    PubMed

    Ghetas, A M; Thaxton, G E; Breedlove, C; van Santen, V L; Toro, H

    2015-03-01

    The population structure of an embryo-attenuated infectious bronchitis virus (IBV) Arkansas (Ark) Delmarva Poultry Industry (DPI)-derived vaccine was characterized during serial passages in chicken embryo kidney (CEK) cells and after back-passage in embryonated chicken eggs (ECE) and in chickens. Both conventional and deep-sequencing results consistently showed population changes occurred during adaptation to CEK cells. Specifically, 13 amino acid (aa) positions seemed to be targets of selection when comparing the vaccine genome prior to and after seven passages in CEK (CEKp7). Amino acid changes occurred at four positions in the spike (S) gene and, at two positions in the S gene, large shifts in frequencies of aa encoding were observed. CEK adaptation shifted the virus population towards homogeneity in S. The changes achieved in the S1 gene in CEKp7 were maintained after a back-passage in ECE. Outside the S gene, aa changes at three positions and large shifts in frequencies at four positions were observed. Synonymous nucleotide changes and changes in noncoding regions of the genome were observed at eight genome positions. Inoculation of early CEK passages into chickens induced higher antibody levels and CEKp4 induced increased respiratory signs compared to CEKp7. From an applied perspective, the fact that CEK adaptation of embryo-attenuated Ark vaccines reduces population heterogeneity, and that changes do not revert after one replication cycle in ECE or in chickens, provides an opportunity to improve commercial ArkDPI-derived vaccines.

  6. Introducing new vaccines in developing countries.

    PubMed

    Kochhar, Sonali; Rath, Barbara; Seeber, Lea D; Rundblad, Gabriella; Khamesipour, Ali; Ali, Mohammad

    2013-12-01

    Vaccines offer the most cost-effective approach to controlling infectious diseases. Access to vaccines remains unequal and suboptimal, particularly in poorer developing countries. Introduction of new vaccines and long-term sustainability of immunization programs will require proactive planning from conception to implementation. International and national coordination efforts as well as local and cultural factors need to be known and accounted for. Adequate infrastructure should be in place for the monitoring of disease burden, vaccine effectiveness and vaccine safety, based on the common terminology and international consensus. This overview paper aims to raise awareness of the importance of introduction efforts for vaccines of special relevance to resource-poor countries. The target audiences are those involved in immunization programs, from planning or oversight roles to frontline providers, as well as health care professionals.

  7. Vaccination using live attenuated Leishmania donovani centrin deleted parasites induces protection in dogs against Leishmania infantum.

    PubMed

    Fiuza, Jacqueline Araújo; Gannavaram, Sreenivas; Santiago, Helton da Costa; Selvapandiyan, Angamuthu; Souza, Daniel Menezes; Passos, Lívia Silva Araújo; de Mendonça, Ludmila Zanandreis; Lemos-Giunchetti, Denise da Silveira; Ricci, Natasha Delaqua; Bartholomeu, Daniella Castanheira; Giunchetti, Rodolfo Cordeiro; Bueno, Lilian Lacerda; Correa-Oliveira, Rodrigo; Nakhasi, Hira L; Fujiwara, Ricardo Toshio

    2015-01-03

    Live attenuated Leishmania donovani parasites such as LdCen(-/-) have been shown elicit protective immunity against leishmanial infection in mice and hamster models. Previously, we have reported on the induction of strong immunogenicity in dogs upon vaccination with LdCen(-/-) including an increase in immunoglobulin isotypes, higher lymphoproliferative response, higher frequencies of activated CD4(+) and CD8(+) T cells, IFN-γ production by CD8(+) T cells, increased secretion of TNF-α and IL-12/IL-23p40 and, finally, decreased secretion of IL-4. To further explore the potential of LdCen(-/-) parasites as vaccine candidates, we performed a 24-month follow up of LdCen(-/-) immunized dogs after challenge with virulent Leishmania infantum, aiming determination of parasite burden by qPCR, antibody production (ELISA) and cellular responses (T cell activation and cytokine production) by flow cytometry and sandwich ELISA. Our data demonstrated that vaccination with a single dose of LdCen(-/-) (without any adjuvant) resulted in the reduction of up to 87.3% of parasite burden after 18 months of virulent challenge. These results are comparable to those obtained with commercially available vaccine in Brazil (Leishmune(®)). The protection was associated with antibody production and CD4(+) and CD8(+) proliferative responses, as well as T cell activation and significantly higher production of IFN-γ, IL-12/IL-23p40 and TNF-α, which was comparable to responses induced by immunization with Leishmune(®), with significant differences when compared to control animals (Placebo). Moreover, only animals immunized with LdCen(-/-) expressed lower levels of IL-4 when compared to animals vaccinated either with Leishmune(®) or PBS. Our results support further studies aiming to demonstrate the potential of genetically modified live attenuated L. donovani vaccine to control L. infantum transmission in endemic areas for CVL.

  8. Development of Experimental Vaccines Against Liver Flukes.

    PubMed

    Yap, Huan Yong; Smooker, Peter M

    2016-01-01

    A multitude of experimental vaccines have been developed against liver flukes in the past. However, there has yet to be the development of a commercial livestock vaccine. Reasons for this may be multiple, and include the lack of identification of the best antigen(s), or the immune response induced by those antigens not being appropriate in either magnitude or polarity (and therefore not protective). Cathepsin proteases are the major component of the excretory/secretory (ES) material of liver flukes in all stages of their life cycle in the definitive host and are the primary antigens of interest for the vaccine development in many studies. Hence, this chapter presents the methodologies of using cathepsin proteases as targeted antigens in recombinant protein and DNA vaccine development to engender protective immune responses against fasciolosis.First, the experimental vaccines developed in the past and the criteria of an effective vaccine for fasciolosis are briefly reviewed. Then flowcharts for recombinant protein vaccine and DNA vaccine development are presented, followed by the detailed materials and methodologies.

  9. Modifications in the polymerase genes of a swine-like triple-reassortant influenza virus to generate live attenuated vaccines against 2009 pandemic H1N1 viruses.

    PubMed

    Pena, Lindomar; Vincent, Amy L; Ye, Jianqiang; Ciacci-Zanella, Janice R; Angel, Matthew; Lorusso, Alessio; Gauger, Philip C; Janke, Bruce H; Loving, Crystal L; Perez, Daniel R

    2011-01-01

    On 11 June 2009, the World Health Organization (WHO) declared that the outbreaks caused by novel swine-origin influenza A (H1N1) virus had reached pandemic proportions. The pandemic H1N1 (H1N1pdm) virus is the predominant influenza virus strain in the human population. It has also crossed the species barriers and infected turkeys and swine in several countries. Thus, the development of a vaccine that is effective in multiple animal species is urgently needed. We have previously demonstrated that the introduction of temperature-sensitive mutations into the PB2 and PB1 genes of an avian H9N2 virus, combined with the insertion of a hemagglutinin (HA) tag in PB1, resulted in an attenuated (att) vaccine backbone for both chickens and mice. Because the new pandemic strain is a triple-reassortant (TR) virus, we chose to introduce the double attenuating modifications into a swine-like TR virus isolate, A/turkey/OH/313053/04 (H3N2) (ty/04), with the goal of producing live attenuated influenza vaccines (LAIV). This genetically modified backbone had impaired polymerase activity and restricted virus growth at elevated temperatures. In vivo characterization of two H1N1 vaccine candidates generated using the ty/04 att backbone demonstrated that this vaccine is highly attenuated in mice, as indicated by the absence of signs of disease, limited replication, and minimum histopathological alterations in the respiratory tract. A single immunization with the ty/04 att-based vaccines conferred complete protection against a lethal H1N1pdm virus infection in mice. More importantly, vaccination of pigs with a ty/04 att-H1N1 vaccine candidate resulted in sterilizing immunity upon an aggressive intratracheal challenge with the 2009 H1N1 pandemic virus. Our studies highlight the safety of the ty/04 att vaccine platform and its potential as a master donor strain for the generation of live attenuated vaccines for humans and livestock.

  10. Vaccination of rhesus macaques with the live-attenuated HSV-1 vaccine VC2 stimulates the proliferation of mucosal T cells and germinal center responses resulting in sustained production of highly neutralizing antibodies.

    PubMed

    Stanfield, Brent A; Pahar, Bapi; Chouljenko, Vladimir N; Veazey, Ronald; Kousoulas, Konstantin G

    2017-01-23

    We have shown that the live-attenuated HSV-1 VC2 vaccine strain with mutations in glycoprotein K (gK) and the membrane protein UL20 is unable to establish latency in vaccinated animals and produces a robust immune response capable of completely protecting mice against lethal vaginal HSV-1 or HSV-2 infections. To better understand the immune response generated by vaccination with VC2, we tested its ability to elicit immune responses in rhesus macaques. Vaccinated animals showed no signs of disease and developed increasing HSV-1 and HSV-2 reactive IgG1 after two booster vaccinations, while IgG subtypes IgG2 and IgG3 remained at low to undetectable levels. All vaccinated animals produced high levels of cross protective neutralizing antibodies. Flow cytometry analysis of cells isolated from draining lymph nodes showed that VC2 vaccination stimulated significant increases in plasmablast (CD27(high)CD38(high)) and mature memory (CD21(-)IgM(-)) B cells. T cell analysis on cells isolated from draining lymph node biopsies demonstrated a statistically significant increase in proliferating (Ki67(+)) follicular T helper cells and regulatory CXCR5(+) CD8(+) cytotoxic T cells. Analysis of plasma isolated two weeks post vaccination showed significant increases in circulating CXCL13 indicating increased germinal center activity. Cells isolated from vaginal biopsy samples collected over the course of the study exhibited vaccination-dependent increases in proliferating (Ki67(+)) CD4(+) and CD8(+) T cell populations. These results suggest that intramuscular vaccination with the live-attenuated HSV-1 VC2 vaccine strain can stimulate robust IgG1 antibody responses that persist for >250days post vaccination. In addition, vaccination lead to the maturation of B cells into plasmablast and mature memory B cells, the expansion of follicular T helper cells, and affects in the mucosal immune responses. These data suggest that the HSV VC2 vaccine induces potent immune responses that could help

  11. A live RSV vaccine with engineered thermostability is immunogenic in cotton rats despite high attenuation.

    PubMed

    Stobart, Christopher C; Rostad, Christina A; Ke, Zunlong; Dillard, Rebecca S; Hampton, Cheri M; Strauss, Joshua D; Yi, Hong; Hotard, Anne L; Meng, Jia; Pickles, Raymond J; Sakamoto, Kaori; Lee, Sujin; Currier, Michael G; Moin, Syed M; Graham, Barney S; Boukhvalova, Marina S; Gilbert, Brian E; Blanco, Jorge C G; Piedra, Pedro A; Wright, Elizabeth R; Moore, Martin L

    2016-12-21

    Respiratory syncytial virus (RSV) is a leading cause of infant hospitalization and there remains no pediatric vaccine. RSV live-attenuated vaccines (LAVs) have a history of safe testing in infants; however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we seek to engineer an RSV LAV with enhanced immunogenicity. Genetic mapping identifies strain line 19 fusion (F) protein residues that correlate with pre-fusion antigen maintenance by ELISA and thermal stability of infectivity in live RSV. We generate a LAV candidate named OE4 which expresses line 19F and is attenuated by codon-deoptimization of non-structural (NS1 and NS2) genes, deletion of the small hydrophobic (SH) gene, codon-deoptimization of the attachment (G) gene and ablation of the secreted form of G. OE4 (RSV-A2-dNS1-dNS2-ΔSH-dGm-Gsnull-line19F) exhibits elevated pre-fusion antigen levels, thermal stability, immunogenicity, and efficacy despite heavy attenuation in the upper and lower airways of cotton rats.

  12. A live RSV vaccine with engineered thermostability is immunogenic in cotton rats despite high attenuation

    PubMed Central

    Stobart, Christopher C.; Rostad, Christina A.; Ke, Zunlong; Dillard, Rebecca S.; Hampton, Cheri M.; Strauss, Joshua D.; Yi, Hong; Hotard, Anne L.; Meng, Jia; Pickles, Raymond J.; Sakamoto, Kaori; Lee, Sujin; Currier, Michael G.; Moin, Syed M.; Graham, Barney S.; Boukhvalova, Marina S.; Gilbert, Brian E.; Blanco, Jorge C. G.; Piedra, Pedro A.; Wright, Elizabeth R.; Moore, Martin L.

    2016-01-01

    Respiratory syncytial virus (RSV) is a leading cause of infant hospitalization and there remains no pediatric vaccine. RSV live-attenuated vaccines (LAVs) have a history of safe testing in infants; however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we seek to engineer an RSV LAV with enhanced immunogenicity. Genetic mapping identifies strain line 19 fusion (F) protein residues that correlate with pre-fusion antigen maintenance by ELISA and thermal stability of infectivity in live RSV. We generate a LAV candidate named OE4 which expresses line 19F and is attenuated by codon-deoptimization of non-structural (NS1 and NS2) genes, deletion of the small hydrophobic (SH) gene, codon-deoptimization of the attachment (G) gene and ablation of the secreted form of G. OE4 (RSV-A2-dNS1-dNS2-ΔSH-dGm-Gsnull-line19F) exhibits elevated pre-fusion antigen levels, thermal stability, immunogenicity, and efficacy despite heavy attenuation in the upper and lower airways of cotton rats. PMID:28000669

  13. Use of reassortant viruses to map attenuating and temperature-sensitive mutations of the Rift Valley fever virus MP-12 vaccine.

    PubMed

    Saluzzo, J F; Smith, J F

    1990-08-01

    A live-attenuated vaccine for Rift Valley fever virus (RVFV), MP-12, has been developed recently by undirected, serial mutagenesis of a RVFV strain (ZH548) isolated during the 1977 epidemic in Egypt. In the present study, the mutations responsible for attenuation of this virus have been examined by analysis of reassortant viruses generated between the vaccine strain and a wild RVFV strain isolated in Senegal. Reassortant viruses were generated efficiently in multiply infected Vero cells, and were readily isolated without application of selective pressures. The origin of the S and M genomic RNA segments in each cloned reassortant virus was determined with monoclonal antibodies capable of differentiating the nucleocapsid protein (S segment marker) or G1 glycoprotein (M segment marker) of the parental strains. The L segment of the vaccine strain was found to contain a temperature-sensitive (ts) mutation, and the origin of the L segment in most reassortants could be inferred by analysis of their ts phenotype. Analysis of the virulence properties of selected reassortant viruses in mice demonstrated that virulence characteristics were under polygenic control, and that at least one mutation capable of independently attenuating the virus existed on each genome segment. The L and M RNA segments were also found to contain ts mutations. These findings suggest that reversion to virulence is unlikely, and further indicate that genetic reassortment with wild-type viruses during a vaccination programme in endemic areas would also be expected to yield attenuated variants.

  14. Vaccines against biologic agents: uses and developments.

    PubMed

    Ales, Noel C; Katial, Rohit K

    2004-03-01

    Although the Geneva protocol that prohibits the use of chemical and biologic weapons was ratified in 1925, many countries failed to accept this protocol: others stipulated retaliation, and some, like the United States, did not ratify the protocol for decades. This delay allowed the continued development of chemical and biologic agents. Members of the health care community are responsible for determining the best way to protect society from the potentially devastating effects of these biologic agents. Ideally,these diseases would be prevented from ever developing into systemic illnesses. In the past, vaccination has been a successful means of eradicating disease. Vaccines remain a hopeful therapy for the future, but time is short,and there are many obstacles.Information regarding bioterrorism agents and their treatments comes mainly from dated data or from in vitro or animal studies that may not apply to human treatment and disease. Additionally, the current threat of bioterrorism does not allow enough time for accurate, well-designed,controlled studies in humans before the release of investigational vaccines. Furthermore, some human studies would not be safe or ethical. Finally,many members of society suffer from illnesses that would put them at high risk to receive prophylactic vaccination. It is therefore naive to believe that vaccines would be the ultimate protection from these agents. In addition to vaccine development, there must be concurrent investigations into disease management and treatment. Even in instances in which vaccination is known to be an effective means of disease protection. biologic agents may be presented in a manner that renders vaccines ineffective. Virulent strains of organisms may be used, more than one organism may be used in tandem to increase virulence, and strains may be selected for antibiotic and vaccine resistance. Genetically engineered strains may use virulence factors other than those targeted in vaccines, and high

  15. Human CD4(+) T Cell Responses to an Attenuated Tetravalent Dengue Vaccine Parallel Those Induced by Natural Infection in Magnitude, HLA Restriction, and Antigen Specificity.

    PubMed

    Angelo, Michael A; Grifoni, Alba; O'Rourke, Patrick H; Sidney, John; Paul, Sinu; Peters, Bjoern; de Silva, Aruna D; Phillips, Elizabeth; Mallal, Simon; Diehl, Sean A; Kirkpatrick, Beth D; Whitehead, Stephen S; Durbin, Anna P; Sette, Alessandro; Weiskopf, Daniela

    2017-03-01

    Dengue virus (DENV) is responsible for growing numbers of infections worldwide and has proven to be a significant challenge for vaccine development. We previously demonstrated that CD8(+) T cell responses elicited by a dengue live attenuated virus (DLAV) vaccine resemble those observed after natural infection. In this study, we screened peripheral blood mononuclear cells (PBMCs) from donors vaccinated with a tetravalent DLAV vaccine (TV005) with pools of dengue virus-derived predicted major histocompatibility complex (MHC) class II binding peptides. The definition of CD4(+) T cell responses after live vaccination is important because CD4(+) T cells are known contributors to host immunity, including cytokine production, help for CD8(+) T and B cells, and direct cytotoxicity against infected cells. While responses to all antigens were observed, DENV-specific CD4(+) T cells were focused predominantly on the capsid and nonstructural NS3 and NS5 antigens. Importantly, CD4(+) T cell responses in vaccinees were similar in magnitude and breadth to those after natural infection, recognized the same antigen hierarchy, and had similar profiles of HLA restriction. We conclude that TV005 vaccination has the capacity to elicit CD4(+) cell responses closely mirroring those observed in a population associated with natural immunity.IMPORTANCE The development of effective vaccination strategies against dengue virus infection is of high global public health interest. Here we study the CD4 T cell responses elicited by a tetravalent live attenuated dengue vaccine and show that they resemble responses seen in humans naturally exposed to dengue virus. This is an important issue, since it is likely that optimal immunity induced by a vaccine requires induction of CD4(+) responses against the same antigens as those recognized as dominant in natural infection. Detailed knowledge of the T cell response may further contribute to the identification of robust correlates of protection against

  16. Human capital gaps in vaccine development: an issue for global vaccine development and global health.

    PubMed

    Cawein, Andrea; Emini, Emilio; Watson, Michael; Dailey, Joanna; Donnelly, John; Tresnan, Dina; Evans, Tom; Plotkin, Stanley; Gruber, William

    2017-02-23

    Despite the success of vaccines in reducing the morbidity and mortality associated with infectious diseases, many infectious diseases, both newly emerging and well known, lack vaccines. The global capability for beginning-to-end vaccine development has become limited, primarily owing to a scarcity of human capital necessary to guide the development of novel vaccines from the laboratory to the marketplace. Here, we identify and discuss the gaps in human capital necessary for robust vaccine development and make recommendations to begin to address these deficiencies.

  17. Military Infectious Diseases Update on Vaccine Development

    DTIC Science & Technology

    2011-01-24

    Research Program (MIDRP) Insect Vector ControlDiagnostics Prevention Treatment Infectious diseases adversely impact military operations. Vaccines...appropriate treatment and aids commanders in the field. Most militarily relevant infectious diseases are transmitted by biting insects and other...based Insect Repellent (1946) Vaccines Protectants Antiparasitic Drugs Research Effort Advanced Development Fielded Products Malaria Rapid

  18. Identifying vaccine targets for anti-leishmanial vaccine development.

    PubMed

    Sundar, Shyam; Singh, Bhawana

    2014-04-01

    Leishmaniasis is a neglected tropical disease spread by an arthropod vector. It remains a significant health problem with an incidence of 0.2–0.4 million visceral leishmaniasis and 0.7–1.2 million cutaneous leishmaniasis cases each year. There are limitations associated with the current therapeutic regimens for leishmaniasis and the fact that after recovery from infection the host becomes immune to subsequent infection therefore, these factors force the feasibility of a vaccine for leishmaniasis. Publication of the genome sequence of Leishmania has paved a new way to understand the pathogenesis and host immunological status therefore providing a deep insight in the field of vaccine research. This review is an effort to study the antigenic targets in Leishmania to develop an anti-leishmanial vaccine.

  19. A history of hookworm vaccine development.

    PubMed

    Schneider, Brent; Jariwala, Amar R; Periago, Maria Victoria; Gazzinelli, Maria Flávia; Bose, Swaroop N; Hotez, Peter J; Diemert, David J; Bethony, Jeffrey M

    2011-11-01

    The human hookworms Necator americanus and Ancylostoma duodenale remain among the most common infections of humans in areas of rural poverty in the developing regions of the world, with an estimated 1 billion people infected with one or more of these parasites. Herein, we review the nearly 100 years of research, development, animal testing, and fieldwork that have led to our current progress in recombinant hookworm vaccines. We begin with the identification of hookworm at the start of the 20th century in Southern US, then discuss the progress in developed countries to eliminate human hookworm infection, and then the industrial development and field use in the 1970s a canine hookworm vaccine(Ancylostoma caninum), and finally our progress to date in the development and clinical testing of an array of recombinant antigens to prevent human hookworm disease from N. americanus infection. Special attention is given to the challenges faced in the development of a vaccine against a blood-feeding nematode, including the epidemiology of infection (high prevalence of infection), pathogenesis (chronic infection that increases with the age of the host), and a robust immune response that fails to confer the protection in the host and a concomitant absence of correlates of protection by a successful vaccine could be developed and tested. Finally, we provide the optimal and acceptable profiles of a human hookworm vaccine, including the proposed indication, target population, and route of administration, as developed by the Human Hookworm Vaccine Initiative, the only group currently working on vaccines targeting this parasite.

  20. Relaxation of purifying selection on the SAD lineage of live attenuated oral vaccines for rabies virus.

    PubMed

    Hughes, Austin L

    2009-09-01

    Analysis of patterns of nucleotide sequence diversity in wild-type rabies virus (RABV) genomes and in the SAD live attenuated oral vaccine lineage was used to test for the relaxation of purifying selection in the latter and provide evidence regarding the genomic regions where such relaxation of selection occurs. The wild-type sequences showed evidence of strong past and ongoing purifying selection both on nonsynonymous sites in coding regions and on non-coding regions, particularly the start, end and 5' UTR regions. SAD vaccine sequences showed a relaxation of purifying selection at nonsynonymous sites in coding regions, resulting a substantial number of amino acid sequence polymorphisms at sites that were invariant in the wild-type sequences. Moreover, SAD vaccine sequences showed high levels of mutation accumulation in the non-coding regions that were most conserved in the wild-type sequences. Understanding the biological effects of the unique mutations accumulated in the vaccine lineage is important because of their potential effects on antigenicity and effectiveness of the vaccine.

  1. Nonclinical Development of BCG Replacement Vaccine Candidates.

    PubMed

    Velmurugan, Kamalakannan; Grode, Leander; Chang, Rosemary; Fitzpatrick, Megan; Laddy, Dominick; Hokey, David; Derrick, Steven; Morris, Sheldon; McCown, David; Kidd, Reginald; Gengenbacher, Martin; Eisele, Bernd; Kaufmann, Stefan H E; Fulkerson, John; Brennan, Michael J

    2013-04-16

    The failure of current Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccines, given to neonates to protect against adult tuberculosis and the risk of using these live vaccines in HIV-infected infants, has emphasized the need for generating new, more efficacious and safer replacement vaccines. With the availability of genetic techniques for constructing recombinant BCG (rBCG) strains containing well-defined gene deletions or insertions, new vaccine candidates are under evaluation at both the preclinical and clinical stages of development. Since most BCG vaccines in use today were evaluated in clinical trials decades ago and are produced by outdated processes, the development of new BCG vaccines offers a number of advantages that include a modern well-defined manufacturing process along with state-of-the-art evaluation of safety and efficacy in target populations. We provide a description of the preclinical development of two novel rBCGs, VPM1002 that was constructed by adding a modified hly gene coding for the protein listeriolysin O (LLO) from Listeria monocytogenes and AERAS-422, which carries a modified pfoA gene coding for the protein perfringolysin O (PFO) from Clostridium perfringens, and three genes from Mycobacterium tuberculosis. Novel approaches like these should be helpful in generating stable and effective rBCG vaccine candidates that can be better characterized than traditional BCG vaccines.

  2. Improved hatchability and efficient protection after in ovo vaccination with live-attenuated H7N2 and H9N2 avian influenza viruses

    PubMed Central

    2011-01-01

    Mass in ovo vaccination with live attenuated viruses is widely used in the poultry industry to protect against various infectious diseases. The worldwide outbreaks of low pathogenic and highly pathogenic avian influenza highlight the pressing need for the development of similar mass vaccination strategies against avian influenza viruses. We have previously shown that a genetically modified live attenuated avian influenza virus (LAIV) was amenable for in ovo vaccination and provided optimal protection against H5 HPAI viruses. However, in ovo vaccination against other subtypes resulted in poor hatchability and, therefore, seemed impractical. In this study, we modified the H7 and H9 hemagglutinin (HA) proteins by substituting the amino acids at the cleavage site for those found in the H6 HA subtype. We found that with this modification, a single dose in ovo vaccination of 18-day old eggs provided complete protection against homologous challenge with low pathogenic virus in ≥70% of chickens at 2 or 6 weeks post-hatching. Further, inoculation of 19-day old egg embryos with 106 EID50 of LAIVs improved hatchability to ≥90% (equivalent to unvaccinated controls) with similar levels of protection. Our findings indicate that the strategy of modifying the HA cleavage site combined with the LAIV backbone could be used for in ovo vaccination against avian influenza. Importantly, with protection conferred as early as 2 weeks post-hatching, with this strategy birds would be protected prior to or at the time of delivery to a farm or commercial operation. PMID:21255403

  3. Antibody response in seropositive multiple sclerosis patients vaccinated with attenuated live varicella zoster virus

    PubMed Central

    Ross, RT; Dawood, MR; Cheang, Mary; Nicolle, Lindsay E

    1996-01-01

    OBJECTIVE: To determine the safety and effectiveness of live attenuated varicella zoster virus (VZV) vaccine (OKA/Merck) on 50 patients with chronic progressive multiple sclerosis (MS), based on the hypothesis that VZV might be the antigen or antigen mimic of MS plus the fact that repeated high antigen doses have produced ‘antigen paralysis’ in experimental allergic encephalomyelitis mice. DESIGN: Fifty patients were randomly selected without controls. They were assessed clinically at entry and on four other occasions over 14 months. Enhanced cranial magnetic resonance imaging (MRI) was performed at entry and at six and 12 months post entry. All were vaccinated after initial assessment and again six weeks later. SETTING: All clinical and laboratory assessments were performed at the Health Sciences Centre, Winnipeg, in the out-patient department. All MRI examinations were performed at the St Boniface General Hospital, Winnipeg, Manitoba. Both are tertiary care hospitals. POPULATION STUDIED: Fifty randomly selected patients with chronic progressive MS, age 18 to 60 years, and a disability status scale of 2.0 or greater were included. Forty-five patients completed the study. INTERVENTIONS: Two vaccinations with attenuated live VZV six weeks apart. RESULTS: All patients were VZV seropositive at entry and all showed an increased antibody level following vaccination. No one was harmed by the vaccine. There may have been some changes in the MS of 15 patients. CONCLUSIONS: It may be reasonable and safe to challenge the process of MS using large doses of the immunogenic proteins of the VZV to induce ‘immune paralysis’. PMID:22514454

  4. Accelerated vaccine development against emerging infectious diseases.

    PubMed

    Leblanc, Pierre R; Yuan, Jianping; Brauns, Tim; Gelfand, Jeffrey A; Poznansky, Mark C

    2012-07-01

    Emerging and re-emerging infectious diseases represent a major challenge to vaccine development since it involves two seemingly contradictory requirements. Rapid and flexible vaccine generation while using technologies and processes that can facilitate accelerated regulatory review. Development in the "-omics" in combination with advances in vaccinology offer novel opportunities to meet these requirements. Here we describe how a consortium of five different organizations from academia and industry is addressing these challenges. This novel approach has the potential to become the new standard in vaccine development allowing timely deployment to avert potential pandemics.

  5. From empiricism to rational design: a personal perspective of the evolution of vaccine development.

    PubMed

    De Gregorio, Ennio; Rappuoli, Rino

    2014-07-01

    Vaccination, which is the most effective medical intervention that has ever been introduced, originated from the observation that individuals who survived a plague or smallpox would not get the disease twice. To mimic the protective effects of natural infection, Jenner - and later Pasteur - inoculated individuals with attenuated or killed disease-causing agents. This empirical approach inspired a century of vaccine development and the effective prophylaxis of many infectious diseases. From the 1980s, several waves of new technologies have enabled the development of novel vaccines that would not have been possible using the empirical approach. The technological revolution in the field of vaccination is now continuing, and it is delivering novel and safer vaccines. In this Timeline article, we provide our views on the transition from empiricism to rational vaccine design.

  6. Microneedle patches for vaccination in developing countries.

    PubMed

    Arya, Jaya; Prausnitz, Mark R

    2016-10-28

    Millions of people die of infectious diseases each year, mostly in developing countries, which could largely be prevented by the use of vaccines. While immunization rates have risen since the introduction of the Expanded Program on Immunization (EPI), there remain major challenges to more effective vaccination in developing countries. As a possible solution, microneedle patches containing an array of micron-sized needles on an adhesive backing have been developed to be used for vaccine delivery to the skin. These microneedle patches can be easily and painlessly applied by pressing against the skin and, in some designs, do not leave behind sharps waste. The patches are single-dose, do not require reconstitution, are easy to administer, have reduced size to simplify storage, transportation and waste disposal, and offer the possibility of improved vaccine immunogenicity, dose sparing and thermostability. This review summarizes vaccination challenges in developing countries and discusses advantages that microneedle patches offer for vaccination to address these challenges. We conclude that microneedle patches offer a powerful new technology that can enable more effective vaccination in developing countries.

  7. Development of Vaccines for Chikungunya Fever.

    PubMed

    Erasmus, Jesse H; Rossi, Shannan L; Weaver, Scott C

    2016-12-15

    Chikungunya fever, an acute and often chronic arthralgic disease caused by the mosquito-borne chikungunya virus (CHIKV), has reemerged since 2004 to cause millions of cases. Because CHIKV exhibits limited antigenic diversity and is not known to be capable of reinfection, a vaccine could serve to both prevent disease and diminish human amplification during epidemic circulation. Here, we review the many promising vaccine platforms and candidates developed for CHIKV since the 1970s, including several in late preclinical or clinical development. We discuss the advantages and limitations of each, as well as the commercial and regulatory challenges to bringing a vaccine to market.

  8. Status of vaccine research and development of vaccines for GBS.

    PubMed

    Heath, Paul T

    2016-06-03

    Streptococcus agalactiae (group B streptococcus (GBS)) is the leading cause of neonatal sepsis and meningitis in many countries. Intrapartum antibiotic strategies have reduced the incidence of early-onset neonatal GBS in a number of countries but have had no impact on late onset GBS infection (LOD). In low/middle income settings, the disease burden remains uncertain although in several countries of Southern Africa appears comparable to or higher than that of high-income countries. As disease may be rapidly fulminating cases can be missed before appropriate samples are obtained and this may lead to underestimation of the true burden. Given the rapid onset and progression within hours of birth as well as the deficiencies in IAP strategies and absence of a solution for preventing LOD, it is clear that administration of a suitable vaccine in pregnancy could provide a better solution in all settings; it should also be cost effective. The current leading vaccine candidates are CPS-protein conjugate vaccines but protein-based vaccines are also in development and one has recently commenced clinical trials.

  9. Rift Valley Fever Virus MP-12 Vaccine Is Fully Attenuated by a Combination of Partial Attenuations in the S, M, and L Segments

    PubMed Central

    Hill, Terence E.; Smith, Jennifer K.; Zhang, Lihong; Juelich, Terry L.; Gong, Bin; Slack, Olga A. L.; Ly, Hoai J.; Lokugamage, Nandadeva; Freiberg, Alexander N.

    2015-01-01

    ABSTRACT Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and characterized by a high rate of abortion in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. RVF is caused by Rift Valley fever virus (RVFV; family Bunyaviridae, genus Phlebovirus), which has a tripartite negative-stranded RNA genome (consisting of the S, M, and L segments). Further spread of RVF into countries where the disease is not endemic may affect the economy and public health, and vaccination is an effective approach to prevent the spread of RVFV. A live-attenuated MP-12 vaccine is one of the best-characterized RVF vaccines for safety and efficacy and is currently conditionally licensed for use for veterinary purposes in the United States. Meanwhile, as of 2015, no other RVF vaccine has been conditionally or fully licensed for use in the United States. The MP-12 strain is derived from wild-type pathogenic strain ZH548, and its genome encodes 23 mutations in the three genome segments. However, the mechanism of MP-12 attenuation remains unknown. We characterized the attenuation of wild-type pathogenic strain ZH501 carrying a mutation(s) of the MP-12 S, M, or L segment in a mouse model. Our results indicated that MP-12 is attenuated by the mutations in the S, M, and L segments, while the mutations in the M and L segments confer stronger attenuation than those in the S segment. We identified a combination of 3 amino acid changes, Y259H (Gn), R1182G (Gc), and R1029K (L), that was sufficient to attenuate ZH501. However, strain MP-12 with reversion mutations at those 3 sites was still highly attenuated. Our results indicate that MP-12 attenuation is supported by a combination of multiple partial attenuation mutations and a single reversion mutation is less likely to cause a reversion to virulence of the MP-12 vaccine. IMPORTANCE Rift Valley fever (RVF) is a mosquito-transmitted viral disease that is endemic to Africa and that has the potential to

  10. Challenges in Veterinary Vaccine Development and Immunization.

    PubMed

    Chambers, Mark A; Graham, Simon P; La Ragione, Roberto M

    2016-01-01

    In approaching the development of a veterinary vaccine, researchers must choose from a bewildering array of options that can be combined to enhance benefit. The choice and combination of options is not just driven by efficacy, but also consideration of the cost, practicality, and challenges faced in licensing the product. In this review we set out the different choices faced by veterinary vaccine developers, highlight some issues, and propose some pressing needs to be addressed.

  11. Vitamin A Deficiency Impairs Adaptive B and T Cell Responses to a Prototype Monovalent Attenuated Human Rotavirus Vaccine and Virulent Human Rotavirus Challenge in a Gnotobiotic Piglet Model

    PubMed Central

    Chattha, Kuldeep S.; Kandasamy, Sukumar; Vlasova, Anastasia N.; Saif, Linda J.

    2013-01-01

    Rotaviruses (RV) are a major cause of gastroenteritis in children. Widespread vitamin A deficiency is associated with reduced efficacy of vaccines and higher incidence of diarrheal infections in children in developing countries. We established a vitamin A deficient (VAD) gnotobiotic piglet model that mimics subclinical vitamin A deficiency in children to study its effects on an oral human rotavirus (HRV) vaccine and virulent HRV challenge. Piglets derived from VAD and vitamin A sufficient (VAS) sows were orally vaccinated with attenuated HRV or mock, with/without supplemental vitamin A and challenged with virulent HRV. Unvaccinated VAD control piglets had significantly lower hepatic vitamin A, higher severity and duration of diarrhea and HRV fecal shedding post-challenge as compared to VAS control pigs. Reduced protection coincided with significantly higher innate (IFNα) cytokine and CD8 T cell frequencies in the blood and intestinal tissues, higher pro-inflammatory (IL12) and 2-3 fold lower anti-inflammatory (IL10) cytokines, in VAD compared to VAS control pigs. Vaccinated VAD pigs had higher diarrhea severity scores compared to vaccinated VAS pigs, which coincided with lower serum IgA HRV antibody titers and significantly lower intestinal IgA antibody secreting cells post-challenge in the former groups suggesting lower anamnestic responses. A trend for higher serum HRV IgG antibodies was observed in VAD vs VAS vaccinated groups post-challenge. The vaccinated VAD (non-vitamin A supplemented) pigs had significantly higher serum IL12 (PID2) and IFNγ (PID6) compared to vaccinated VAS groups suggesting higher Th1 responses in VAD conditions. Furthermore, regulatory T-cell responses were compromised in VAD pigs. Supplemental vitamin A in VAD pigs did not fully restore the dysregulated immune responses to AttHRV vaccine or moderate virulent HRV diarrhea. Our findings suggest that that VAD in children in developing countries may partially contribute to more severe

  12. A Low Gastric pH Mouse Model to Evaluate Live Attenuated Bacterial Vaccines

    PubMed Central

    Brenneman, Karen E.; Willingham, Crystal; Kilbourne, Jacquelyn A.; 3rd, Roy Curtiss; Roland, Kenneth L.

    2014-01-01

    The low pH of the stomach serves as a barrier to ingested microbes and must be overcome or bypassed when delivering live bacteria for vaccine or probiotic applications. Typically, the impact of stomach acidity on bacterial survival is evaluated in vitro, as there are no small animal models to evaluate these effects in vivo. To better understand the effect of this low pH barrier to live attenuated Salmonella vaccines, which are often very sensitive to low pH, we investigated the value of the histamine mouse model for this application. A low pH gastric compartment was transiently induced in mice by the injection of histamine. This resulted in a gastric compartment of approximately pH 1.5 that was capable of distinguishing between acid-sensitive and acid-resistant microbes. Survival of enteric microbes during gastric transit in this model directly correlated with their in vitro acid resistance. Because many Salmonella enterica serotype Typhi vaccine strains are sensitive to acid, we have been investigating systems to enhance the acid resistance of these bacteria. Using the histamine mouse model, we demonstrate that the in vivo survival of S. Typhi vaccine strains increased approximately 10-fold when they carried a sugar-inducible arginine decarboxylase system. We conclude that this model will be a useful for evaluating live bacterial preparations prior to clinical trials. PMID:24489912

  13. Evaluation of eight live attenuated vaccine candidates for protection against challenge with virulent Mycobacterium avium subspecies paratuberculosis in mice.

    PubMed

    Bannantine, John P; Everman, Jamie L; Rose, Sasha J; Babrak, Lmar; Katani, Robab; Barletta, Raúl G; Talaat, Adel M; Gröhn, Yrjö T; Chang, Yung-Fu; Kapur, Vivek; Bermudez, Luiz E

    2014-01-01

    Johne's disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), which results in serious economic losses worldwide in farmed livestock such as cattle, sheep, and goats. To control this disease, an effective vaccine with minimal adverse effects is needed. In order to identify a live vaccine for Johne's disease, we evaluated eight attenuated mutant strains of MAP using a C57BL/6 mouse model. The persistence of the vaccine candidates was measured at 6, 12, and 18 weeks post vaccination. Only strains 320, 321, and 329 colonized both the liver and spleens up until the 12-week time point. The remaining five mutants showed no survival in those tissues, indicating their complete attenuation in the mouse model. The candidate vaccine strains demonstrated different levels of protection based on colonization of the challenge strain in liver and spleen tissues at 12 and 18 weeks post vaccination. Based on total MAP burden in both tissues at both time points, strain 315 (MAP1566::Tn5370) was the most protective whereas strain 318 (intergenic Tn5367 insertion between MAP0282c and MAP0283c) had the most colonization. Mice vaccinated with an undiluted commercial vaccine preparation displayed the highest bacterial burden as well as enlarged spleens indicative of a strong infection. Selected vaccine strains that showed promise in the mouse model were moved forward into a goat challenge model. The results suggest that the mouse trial, as conducted, may have a relatively poor predictive value for protection in a ruminant host such as goats.

  14. The Development of an AIDS Mucosal Vaccine

    PubMed Central

    Tang, Xian; Chen, Zhiwei

    2010-01-01

    It is well known that mucosal tissues contain the largest surface area of the human body and are the front line of natural host defense against various pathogens. In fact, more than 80% of infectious disease pathogens probably gain entry into the susceptible human hosts through open mucosal surfaces. Human immunodeficiency virus type one (HIV-1), a mainly sexually transmitted virus, also primarily targets the vaginal and gastrointestinal mucosa as entry sites for viral transmission, seeding, replication and amplification. Since HIV-1 establishes its early replication in vaginal or rectal mucosal tissues, the induction of sufficient mucosal immunity at the initial site of HIV-1 transmission becomes essential for a protective vaccine. However, despite the fact that current conventional vaccine strategies have remained unsuccessful in preventing HIV-1 infection, sufficient financial support and resources have yet to be given to develop a vaccine able to elicit protective mucosal immunity against sexual transmissions. Interestingly, Chinese ancestors invented variolation through intranasal administration about one thousand years ago, which led to the discovery of a successful smallpox vaccine and the final eradication of the disease. It is the hope for all mankind that the development of a mucosal AIDS vaccine will ultimately help control the AIDS pandemic. In order to discover an effective mucosal AIDS vaccine, it is necessary to have a deep understanding of mucosal immunology and to test various mucosal vaccination strategies. PMID:21994611

  15. Tularemia vaccine development: paralysis or progress?

    PubMed Central

    Sunagar, Raju; Kumar, Sudeep; Franz, Brian J; Gosselin, Edmund J

    2016-01-01

    Francisella tularensis (Ft) is a gram-negative intercellular pathogen and category A biothreat agent. However, despite 15 years of strong government investment and intense research focused on the development of a US Food and Drug Administration-approved vaccine against Ft, the primary goal remains elusive. This article reviews research efforts focused on developing an Ft vaccine, as well as a number of important factors, some only recently recognized as such, which can significantly impact the development and evaluation of Ft vaccine efficacy. Finally, an assessment is provided as to whether a US Food and Drug Administration-approved Ft vaccine is likely to be forthcoming and the potential means by which this might be achieved. PMID:27200274

  16. B-cell responses after intranasal vaccination with the novel attenuated Bordetella pertussis vaccine strain BPZE1 in a randomized phase I clinical trial.

    PubMed

    Jahnmatz, Maja; Amu, Sylvie; Ljungman, Margaretha; Wehlin, Lena; Chiodi, Francesca; Mielcarek, Nathalie; Locht, Camille; Thorstensson, Rigmor

    2014-06-05

    Despite high vaccination coverage, pertussis is still a global concern in infant morbidity and mortality, and improved pertussis vaccines are needed. A live attenuated Bordetella pertussis strain, named BPZE1, was designed as an intranasal vaccine candidate and has recently been tested in man in a phase I clinical trial. Here, we report the evaluation of the B-cell responses after vaccination with BPZE1. Forty-eight healthy males with no previous pertussis-vaccination were randomized into one of three dose-escalating groups or into a placebo group. Plasma blast- and memory B-cell responses were evaluated by ELISpot against three different pertussis antigens: pertussis toxin, filamentous haemagglutinin and pertactin. Seven out of the 36 subjects who had received the vaccine were colonized by BPZE1, and significant increases in the memory B-cell response were detected against all three tested antigens in the culture-positive subjects between days 0 and 28 post-vaccination. The culture-positive subjects also mounted a significant increase in the filamentous haemagglutinin-specific plasma blast response between days 7 and 14 post-vaccination. No response could be detected in the culture-negatives or in the placebo group post-vaccination. These data show that BPZE1 is immunogenic in humans and is therefore a promising candidate for a novel pertussis vaccine. This trial is registered at ClinicalTrials.gov (NCT01188512).

  17. An overview of live attenuated recombinant pseudorabies viruses for use as novel vaccines.

    PubMed

    Dong, Bo; Zarlenga, Dante S; Ren, Xiaofeng

    2014-01-01

    Pseudorabies virus (PRV) is a double-stranded, DNA-based swine virus with a genome approximating 150 kb in size. PRV has many nonessential genes which can be replaced with genes encoding heterologous antigens but without deleterious effects on virus propagation. Recombinant PRVs expressing both native and foreign antigens are able to stimulate immune responses. In this paper, we review the current status of live attenuated recombinant PRVs and live PRV-based vector vaccines with potential for controlling viral infections in animals.

  18. [Studies on virulence of HIV and development of non-virulent live AIDS vaccine using monkeys].

    PubMed

    Hayami, Masanori; Horiuchi, Reii

    2004-06-01

    A great effort for developing AIDS vaccine has been carried out in the world, designed by various new ideas based on basic research information obtained in recent virology and immunology. Withall it, to obtain effective AIDS vaccine is considered skeptical. One of the reasons of its difficulty is a lack of experimental animals susceptible to HIV-1. In our laboratory, we have succeeded in developing chimeric SIV having 3' half of HIV-1 genome including env (SHIV), which is infectious to macaque monkeys. One of SHIVs has been proved nonpathogenic in monkeys from various aspects and it afforded protective immunity to monkeys against pathogenic SHIV challenge infection. Now, we are trying to develop anti-HIV live attenuated vaccines using the nonpathogenic SHIV as a starting material. In the history of virus vaccine, live attenuated vaccines have been proved most effective in measles and polio-myelitis. However, it is not clear whether nonpathogenic HIV exists or not. Futhermore, even if nonpathogenic HIV could be obtained, there is possibility that it will easily mutate to pathogenic one. Therefore, to develop live attenuated AIDS vaccine is considered dangerous. In this article, We will introduce our research on SHIV pathogenicity using monkeys and hypothesize possibility to obtain nonpathogenic HIV which is speculated from the origin and evolution of HIV/SIV. To clarify virulence and nonvirulence of HIV and to obtain nonpathogenic virus are not only applied research but also basic science to dissolve the fundemental question why HIV can induce the disease.

  19. An aerial baiting system for the distribution of attenuated or recombinant rabies vaccines for foxes, raccoons, and skunks.

    PubMed

    Johnston, D H; Voigt, D R; MacInnes, C D; Bachmann, P; Lawson, K F; Rupprecht, C E

    1988-01-01

    An aerial baiting system was developed to deliver oral rabies vaccines to wild carnivore vectors of rabies, e.g., red fox, striped skunk, and raccoon. The bait consists of a polyethylene bag that contains either a 30-g hamburger ball or a 25-mL cube of polyurethane sponge coated with a wax-beef tallow mixture containing 100-150 mg of tetracycline as a biomarker. Attractants used with the sponge were added to the bag (e.g., liver slurry, cheeses, fish oils, or fruits). Baits (greater than 80,000) were dropped from light aircraft at densities of 18-120 baits/km2 over test areas in Ontario and Pennsylvania. Rates of bait acceptance were assessed by the presence of fluorescent tetracycline deposits in the teeth of animals obtained from hunters and trappers. Bait acceptance reached 74% in foxes, 54% in skunks, 43% in raccoons, and 85% in coyotes in the Ontario trials; bait acceptance by raccoons in a small trial in Pennsylvania reached 76%. Also, 66% of juvenile foxes that ate baits ate a second bait 7 or more days after eating the first, thus giving the potential for a booster effect. The cost of aerial distribution of bait (excluding cost of bait and vaccine) in Canadian dollars was $1.45/km2. The aerial distribution system is capable of economically reaching a high proportion of foxes, skunks, and raccoons over large areas. Trials with attenuated ERA (Evelyn-Rokitnicki-Abelseth) vaccines are under way in Ontario.

  20. Safety and immunogenicity of a rederived, live-attenuated dengue virus vaccine in healthy adults living in Thailand: a randomized trial.

    PubMed

    Watanaveeradej, Veerachai; Gibbons, Robert V; Simasathien, Sriluck; Nisalak, Ananda; Jarman, Richard G; Kerdpanich, Angkool; Tournay, Elodie; De La Barrerra, Rafael; Dessy, Francis; Toussaint, Jean-François; Eckels, Kenneth H; Thomas, Stephen J; Innis, Bruce L

    2014-07-01

    Safety and immunogenicity of two formulations of a live-attenuated tetravalent dengue virus (TDEN) vaccine produced using rederived master seeds from a precursor vaccine were tested against a placebo control in a phase II, randomized, double blind trial (NCT00370682). Two doses were administered 6 months apart to 120 healthy, predominantly flavivirus-primed adults (87.5% and 97.5% in the two vaccine groups and 92.5% in the placebo group). Symptoms and signs reported after vaccination were mild to moderate and transient. There were no vaccine-related serious adverse events or dengue cases reported. Asymptomatic, low-level viremia (dengue virus type 2 [DENV-2], DENV-3, or DENV-4) was detected in 5 of 80 vaccine recipients. One placebo recipient developed a subclinical natural DENV-1 infection. All flavivirus-unprimed subjects and at least 97.1% of flavivirus-primed subjects were seropositive to antibodies against all four DENV types 1 and 3 months post-TDEN dose 2. The TDEN vaccine was immunogenic with an acceptable safety profile in flavivirus-primed adults.

  1. Growth restriction of an experimental live attenuated human parainfluenza virus type 2 vaccine in human ciliated airway epithelium in vitro parallels attenuation in African green monkeys

    PubMed Central

    Schaap-Nutt, Anne; Scull, Margaret A.; Schmidt, Alexander C.; Murphy, Brian R.; Pickles, Raymond J.

    2010-01-01

    Human parainfluenza viruses (HPIVs) are common causes of severe pediatric respiratory viral disease. We characterized wild-type HPIV2 infection in an in vitro model of human airway epithelium (HAE) and found that the virus replicates to high titer, sheds apically, targets ciliated cells, and induces minimal cytopathology. Replication of an experimental, live attenuated HPIV2 vaccine strain, containing both temperature sensitive (ts) and non-ts attenuating mutations, was restricted >30-fold compared to rHPIV2-WT in HAE at 32°C and exhibited little productive replication at 37°C. This restriction paralleled attenuation in the upper and lower respiratory tract of African green monkeys, supporting the HAE model as an appropriate and convenient system for characterizing HPIV2 vaccine candidates. PMID:20139039

  2. Next-Generation Bacillus anthracis Live Attenuated Spore Vaccine Based on the htrA(-) (High Temperature Requirement A) Sterne Strain.

    PubMed

    Chitlaru, Theodor; Israeli, Ma'ayan; Bar-Haim, Erez; Elia, Uri; Rotem, Shahar; Ehrlich, Sharon; Cohen, Ofer; Shafferman, Avigdor

    2016-01-06

    Anthrax is a lethal disease caused by the gram-positive spore-producing bacterium Bacillus anthracis. Live attenuated vaccines, such as the nonencapsulated Sterne strain, do not meet the safety standards mandated for human use in the Western world and are approved for veterinary purposes only. Here we demonstrate that disrupting the htrA gene, encoding the chaperone/protease HtrA (High Temperature Requirement A), in the virulent Bacillus anthracis Vollum strain results in significant virulence attenuation in guinea pigs, rabbits and mice, underlying the universality of the attenuated phenotype associated with htrA knockout. Accordingly, htrA disruption was implemented for the development of a Sterne-derived safe live vaccine compatible with human use. The novel B. anthracis SterneΔhtrA strain secretes functional anthrax toxins but is 10-10(4)-fold less virulent than the Sterne vaccine strain depending on animal model (mice, guinea pigs, or rabbits). In spite of this attenuation, double or even single immunization with SterneΔhtrA spores elicits immune responses which target toxaemia and bacteremia resulting in protection from subcutaneous or respiratory lethal challenge with a virulent strain in guinea pigs and rabbits. The efficacy of the immune-protective response in guinea pigs was maintained for at least 50 weeks after a single immunization.

  3. Developments in Viral Vector-Based Vaccines

    PubMed Central

    Ura, Takehiro; Okuda, Kenji; Shimada, Masaru

    2014-01-01

    Viral vectors are promising tools for gene therapy and vaccines. Viral vector-based vaccines can enhance immunogenicity without an adjuvant and induce a robust cytotoxic T lymphocyte (CTL) response to eliminate virus-infected cells. During the last several decades, many types of viruses have been developed as vaccine vectors. Each has unique features and parental virus-related risks. In addition, genetically altered vectors have been developed to improve efficacy and safety, reduce administration dose, and enable large-scale manufacturing. To date, both successful and unsuccessful results have been reported in clinical trials. These trials provide important information on factors such as toxicity, administration dose tolerated, and optimized vaccination strategy. This review highlights major viral vectors that are the best candidates for clinical use. PMID:26344749

  4. Prospects for the development of fungal vaccines.

    PubMed

    Deepe, G S

    1997-10-01

    In an era that emphasizes the term "cost-effective," vaccines are the ideal solution to preventing disease at a relatively low cost to society. Much of the previous emphasis has been on childhood scourges such as measles, mumps, rubella, poliomyelitis, and Haemophilus influenzae type b. The concept of vaccines for fungal diseases has had less impact because of the perceived limited problem. However, fungal diseases have become increasingly appreciated as serious medical problems that require recognition and aggressive management. The escalation in the incidence and prevalence of infection has prompted a renewed interest in vaccine development. Herein, I discuss the most recent developments in the search for vaccines to combat fungal infections. Investigators have discovered several inert substances from various fungi that can mediate protection in animal models. The next challenge will be to find the suitable mode of delivery for these immunogens.

  5. A new generation of modified live-attenuated avian influenza viruses using a two-strategy combination as potential vaccine candidates.

    PubMed

    Song, Haichen; Nieto, Gloria Ramirez; Perez, Daniel R

    2007-09-01

    In light of the recurrent outbreaks of low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI), there is a pressing need for the development of vaccines that allow rapid mass vaccination. In this study, we introduced by reverse genetics temperature-sensitive mutations in the PB1 and PB2 genes of an avian influenza virus, A/Guinea Fowl/Hong Kong/WF10/99 (H9N2) (WF10). Further genetic modifications were introduced into the PB1 gene to enhance the attenuated (att) phenotype of the virus in vivo. Using the att WF10 as a backbone, we substituted neuraminidase (NA) for hemagglutinin (HA) for vaccine purposes. In chickens, a vaccination scheme consisting of a single dose of an att H7N2 vaccine virus at 2 weeks of age and subsequent challenge with the wild-type H7N2 LPAI virus resulted in complete protection. We further extended our vaccination strategy against the HPAI H5N1. In this case, we reconstituted an att H5N1 vaccine virus, whose HA and NA genes were derived from an Asian H5N1 virus. A single-dose immunization in ovo with the att H5N1 vaccine virus in 18-day-old chicken embryos resulted in more than 60% protection for 4-week-old chickens and 100% protection for 9- to 12-week-old chickens. Boosting at 2 weeks posthatching provided 100% protection against challenge with the HPAI H5N1 virus for chickens as young as 4 weeks old, with undetectable virus shedding postchallenge. Our results highlight the potential of live att avian influenza vaccines for mass vaccination in poultry.

  6. Cell-Associated Flagella Enhance the Protection Conferred by Mucosally-Administered Attenuated Salmonella Paratyphi A Vaccines

    PubMed Central

    Gat, Orit; Galen, James E.; Tennant, Sharon; Simon, Raphael; Blackwelder, William C.; Silverman, David J.; Pasetti, Marcela F.; Levine, Myron M.

    2011-01-01

    Background Antibiotic-resistant Salmonella enterica serovar Paratyphi A, the agent of paratyphoid A fever, poses an emerging public health dilemma in endemic areas of Asia and among travelers, as there is no licensed vaccine. Integral to our efforts to develop a S. Paratyphi A vaccine, we addressed the role of flagella as a potential protective antigen by comparing cell-associated flagella with exported flagellin subunits expressed by attenuated strains. Methodology S. Paratyphi A strain ATCC 9150 was first deleted for the chromosomal guaBA locus, creating CVD 1901. Further chromosomal deletions in fliD (CVD 1901D) or flgK (CVD 1901K) were then engineered, resulting in the export of unpolymerized FliC, without impairing its overall expression. The virulence of the resulting isogenic strains was examined using a novel mouse LD50 model to accommodate the human-host restricted S. Paratyphi A. The immunogenicity of the attenuated strains was then tested using a mouse intranasal model, followed by intraperitoneal challenge with wildtype ATCC 9150. Results Mucosal (intranasal) immunization of mice with strain CVD 1901 expressing cell-associated flagella conferred superior protection (vaccine efficacy [VE], 90%) against a lethal intraperitoneal challenge, compared with the flagellin monomer-exporting mutants CVD 1901K (30% VE) or CVD 1901D (47% VE). The superior protection induced by CVD 1901 with its cell-attached flagella was associated with an increased IgG2a∶IgG1 ratio of FliC-specific antibodies with enhanced opsonophagocytic capacity. Conclusions Our results clearly suggest that enhanced anti-FliC antibody-mediated clearance of S. Paratyphi A by phagocytic cells, induced by vaccines expressing cell-associated rather than exported FliC, might be contributing to the vaccine-induced protection from S. Paratyphi A challenge in vivo. We speculate that an excess of IgG1 anti-FliC antibodies induced by the exported FliC may compete with the IgG2a subtype and block

  7. Evaluation and improvement of a single nucleotide polymorphism-based PCR assay for rapid differentiation of live attenuated vaccine strains from field isolates of Erysipelothrix rhusiopathiae.

    PubMed

    Zhu, Weifeng; Li, Jingtao; Wang, Ya; Kang, Chao; Jin, Meilin; Chen, Huanchun

    2016-11-01

    A single nucleotide polymorphism-based PCR assay has been developed to differentiate the attenuated vaccine strain used in Japan from field isolates of Erysipelothrix rhusiopathiae found in pigs. However, this assay has been evaluated with only Japanese strains and isolates; therefore, it is unknown whether it could be used in other countries with E. rhusiopathiae strains and isolates of different genetic backgrounds. In our study, the PCR assay was evaluated using Chinese E. rhusiopathiae vaccine strains and field isolates. The PCR assay was able to differentiate the attenuated vaccine strains from the field isolates of E. rhusiopathiae in China but with a pattern different from that observed in Japan (only a single nucleotide polymorphism was detected in the Chinese vaccine strains compared with 5 in the Japanese vaccine strains). Importantly, either a DNA polymerase without 3' to 5' exonuclease activity or an exo(+) polymerase with an antibody inhibiting the proofreading activity was required. In conclusion, after evaluation and improvement, this fast differentiation assay can be extended from Japan to China.

  8. A history of hookworm vaccine development

    PubMed Central

    Schneider, Brent; Jariwala, Amar R.; Periago, Maria Victoria; Gazzinelli, Maria Flávia; Bose, Swaroop N.; Hotez, Peter J.; Diemert, David J.

    2011-01-01

    The human hookworms Necator americanus and Ancylostoma duodenale remain among the most common infections of humans in areas of rural poverty in the developing regions of the world, with an estimated 1 billion people infected with one or more of these parasites. Herein, we review the nearly 100 years of research, development, animal testing, and fieldwork that have led to our current progress in recombinant hookworm vaccines. We begin with the identification of hookworm at the start of the 20th century in Southern US, then discuss the progress in developed countries to eliminate human hookworm infection, and then the industrial development and field use in the 1970s a canine hookworm vaccine(Ancylostoma caninum), and finally our progress to date in the development and clinical testing of an array of recombinant antigens to prevent human hookworm disease from N. americanus infection. Special attention is given to the challenges faced in the development of a vaccine against a blood-feeding nematode, including the epidemiology of infection (high prevalence of infection), pathogenesis (chronic infection that increases with the age of the host), and a robust immune response that fails to confer the protection in the host and a concomitant absence of correlates of protection by a successful vaccine could be developed and tested. Finally, we provide the optimal and acceptable profiles of a human hookworm vaccine, including the proposed indication, target population, and route of administration, as developed by the Human Hookworm Vaccine Initiative, the only group currently working on vaccines targeting this parasite. PMID:22064562

  9. Effect of size and temperature at vaccination on immunization and protection conferred by a live attenuated Francisella noatunensis immersion vaccine in red hybrid tilapia.

    PubMed

    Soto, Esteban; Brown, Nicholas; Gardenfors, Zackarias O; Yount, Shaun; Revan, Floyd; Francis, Stewart; Kearney, Michael T; Camus, Alvin

    2014-12-01

    Francisella noatunensis subsp. orientalis (Fno) is a pleomorphic, facultative intracellular, Gram-negative, emerging bacterial pathogen of marine and fresh water fish with worldwide distribution. In this study, the efficacy of an attenuated Fno intracellular growth locus C (iglC) mutant was evaluated for use as a live immersion vaccine, when administered to hybrid tilapia at two different stages of growth (5 g fry and 10 g fingerlings) and at two temperatures (25 °C and 30 °C). To determine vaccine efficacy, mortality, days to first death, and Fno genome equivalents (GE) in the spleens of survivors, as well as serum and mucus antibody levels, were evaluated after 30 d in fish challenged with a wild type virulent strain. Both size and temperature at vaccination played an important role in immunization and protection. Fry vaccinated at 25 °C were not protected when compared to non-vaccinated fry at 25 °C (p = 0.870). In contrast, 5 g fry vaccinated at 30 °C were significantly protected compared to non-vaccinated fry at 30 °C (p = 0.038). Although lower mortalities occurred, 10 g fingerlings vaccinated at 25 °C were not protected, compared to non-vaccinated fingerlings at 25 °C (p = 0.328), while, 10 g fingerlings vaccinated at 30 °C were significantly protected, compared to non-vaccinated fingerlings at 30 °C (p = 0.038). Additionally, overall mortality of 5 g fish was significantly higher than in 10 g fish. Mortality was also significantly higher in fish subjected to a 30 to 25 °C temperature change one week prior to challenge, than in fish maintained at the same temperature during vaccination and challenge. This information demonstrates that both temperature and size at vaccination are important factors when implementing immunization prophylaxis in cultured tilapia.

  10. Recent Developments in Livestock and Wildlife Brucellosis Vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Live attenuated brucellosis vaccines have been available for protecting domestic livestock against B. melitensis or B. abortus for more than 60 years. Current vaccines are effective in preventing abortion and transmission of brucellosis, but poor at preventing infection or seroconversion. In addit...

  11. Lessons from the cat: development of vaccines against lentiviruses.

    PubMed

    Dunham, Stephen P

    2006-07-15

    Feline immunodeficiency virus (FIV) is a natural infection of domestic cats, which produces a disease with many similarities to human immunodeficiency virus (HIV) infection in man. The virus is an important cause of morbidity and mortality in pet cats worldwide. As such an effective vaccine is desirable both for its use in veterinary medicine and also as a model for the development of an HIV vaccine. A large number of candidate vaccines have been tested against feline immunodeficiency virus. These include inactivated virus and infected cell vaccines, DNA and viral vectored vaccines, subunit and peptide vaccines and vaccines using bacterial vectors. Ultimately, the development of inactivated virus and infected cell vaccines led to the release of the first licensed vaccine against FIV, in 2002. This review highlights some of the difficulties associated with the development of lentiviral vaccines and some of the lessons that have been learned in the FIV model that are of particular relevance to the development of HIV vaccines.

  12. Workshop report: Schistosomiasis vaccine clinical development and product characteristics.

    PubMed

    Mo, Annie X; Colley, Daniel G

    2016-02-17

    A schistosomiasis vaccine meeting was organized to evaluate the utility of a vaccine in public health programs, to discuss clinical development paths, and to define basic product characteristics for desirable vaccines to be used in the context of schistosomiasis control and elimination programs. It was concluded that clinical evaluation of a schistosomiasis vaccine is feasible with appropriate trial design and tools. Some basic Preferred Product Characteristics (PPC) for a human schistosomiasis vaccine and for a veterinary vaccine for bovine use were also proposed.

  13. Efficient strategy for constructing duck enteritis virus-based live attenuated vaccine against homologous and heterologous H5N1 avian influenza virus and duck enteritis virus infection.

    PubMed

    Zou, Zhong; Hu, Yong; Liu, Zhigang; Zhong, Wei; Cao, Hangzhou; Chen, Huanchun; Jin, Meilin

    2015-04-16

    Duck is susceptible to many pathogens, such as duck hepatitis virus, duck enteritis virus (DEV), duck tembusu virus, H5N1 highly pathogenic avian influenza virus (HPAIV) in particular. With the significant role of duck in the evolution of H5N1 HPAIV, control and eradication of H5N1 HPAIV in duck through vaccine immunization is considered an effective method in minimizing the threat of a pandemic outbreak. Consequently, a practical strategy to construct a vaccine against these pathogens should be determined. In this study, the DEV was examined as a candidate vaccine vector to deliver the hemagglutinin (HA) gene of H5N1, and its potential as a polyvalent vaccine was evaluated. A modified mini-F vector was inserted into the gB and UL26 gene junction of the attenuated DEV vaccine strain C-KCE genome to generate an infectious bacterial artificial chromosome (BAC) of C-KCE (vBAC-C-KCE). The HA gene of A/duck/Hubei/xn/2007 (H5N1) was inserted into the C-KCE genome via the mating-assisted genetically integrated cloning (MAGIC) to generate the recombinant vector pBAC-C-KCE-HA. A bivalent vaccine C-KCE-HA was developed by eliminating the BAC backbone. Ducks immunized with C-KCE-HA induced both the cross-reactive antibodies and T cell response against H5. Moreover, C-KCE-HA-immunized ducks provided rapid and long-lasting protection against homologous and heterologous HPAIV H5N1 and DEV clinical signs, death, and primary viral replication. In conclusion, our BAC-C-KCE is a promising platform for developing a polyvalent live attenuated vaccine.

  14. Rational design of genetically stable, live-attenuated poliovirus vaccines of all three serotypes: relevance to poliomyelitis eradication.

    PubMed

    Macadam, Andrew J; Ferguson, Geraldine; Stone, David M; Meredith, Janet; Knowlson, Sarah; Auda, Ghazi; Almond, Jeffrey W; Minor, Philip D

    2006-09-01

    The global eradication of poliomyelitis caused by wild-type virus is likely to be completed within the next few years, despite immense logistic and political difficulties, and may ultimately be followed by the cessation of vaccination. However, the existing live-attenuated vaccines have the potential to revert to virulence, causing occasional disease, and viruses can be shed by immunocompromised individuals for prolonged periods of time. Moreover, several outbreaks of poliomyelitis have been shown to be caused by viruses derived from the Sabin vaccine strains. The appearance of such strains depends on the prevailing circumstances but poses a severe obstacle to strategies for stopping vaccination. Vaccine strains that are incapable of reversion at a measurable rate would provide a possible solution. Here, we describe the constructions of strains of type 3 poliovirus that are stabilized by the introduction of four mutations in the 5' noncoding region compared to the present vaccine. The strains are genetically and phenotypically stable under conditions where the present vaccine loses the attenuating mutation in the 5' noncoding region completely. Type 1 and type 2 strains in which the entire 5' noncoding regions of Sabin 1 and Sabin 2 were replaced exactly with that of one of the type 3 strains were also constructed. The genetic stability of 5' noncoding regions of these viruses matched that of the type 3 strains, but significant phenotypic reversion occurred, illustrating the potential limitations of a rational approach to the genetic stabilization of live RNA virus vaccines.

  15. Development of Vaccines Against Burkholderia Pseudomallei

    PubMed Central

    Patel, Natasha; Conejero, Laura; De Reynal, Melanie; Easton, Anna; Bancroft, Gregory J.; Titball, Richard W.

    2011-01-01

    Burkholderia pseudomallei is a Gram-negative bacterium which is the causative agent of melioidosis, a disease which carries a high mortality and morbidity rate in endemic areas of South East Asia and Northern Australia. At present there is no available human vaccine that protects against B. pseudomallei, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. This review considers the multiple elements of melioidosis vaccine research including: (i) the immune responses required for protective immunity, (ii) animal models available for preclinical testing of potential candidates, (iii) the different experimental vaccine strategies which are being pursued, and (iv) the obstacles and opportunities for eventual registration of a licensed vaccine in humans. PMID:21991263

  16. A live-attenuated influenza vaccine for H3N2 canine influenza virus.

    PubMed

    Rodriguez, Laura; Nogales, Aitor; Reilly, Emma C; Topham, David J; Murcia, Pablo R; Parrish, Colin R; Martinez Sobrido, Luis

    2017-04-01

    Canine influenza is a contagious respiratory disease in dogs caused by two subtypes (H3N2 and H3N8) of canine influenza virus (CIV). Currently, only inactivated influenza vaccines (IIVs) are available for the prevention of CIVs. Historically, live-attenuated influenza vaccines (LAIVs) have been shown to produce better immunogenicity and protection efficacy than IIVs. Here, we have engineered a CIV H3N2 LAIV by using the internal genes of a previously described CIV H3N8 LAIV as a master donor virus (MDV) and the surface HA and NA genes of a circulating CIV H3N2 strain. Our findings show that CIV H3N2 LAIV replicates efficiently at low temperature but its replication is impaired at higher temperatures. The CIV H3N2 LAIV was attenuated in vivo but induced better protection efficacy in mice against challenge with wild-type CIV H3N2 than a commercial CIV H3N2 IIV. This is the first description of a LAIV for the prevention of CIV H3N2 in dogs.

  17. Comparative Immunogenicities of Frozen and Refrigerated Formulations of Live Attenuated Influenza Vaccine in Healthy Subjects▿

    PubMed Central

    Block, Stan L.; Reisinger, Keith S.; Hultquist, Micki; Walker, Robert E.

    2007-01-01

    The frozen version of live attenuated influenza vaccine (LAIV; FluMist) was compared with a newly licensed, refrigerated formulation, the cold-adapted influenza vaccine, trivalent (CAIV-T), for their immunogenicity, safety, and tolerability in healthy subjects 5 to 49 years of age. Eligible subjects were randomized 1:1 to receive CAIV-T or frozen LAIV. Subjects 5 to 8 years of age received two doses of vaccine 46 to 60 days apart; subjects 9 to 49 years of age received one dose of vaccine. Equivalent immunogenicities were defined as serum hemagglutination inhibition (HAI) geometric mean titer (GMT) ratios >0.5 and <2.0 for each of the three vaccine-specific strains. A total of 376 subjects 5 to 8 years of age and 566 subjects 9 to 49 years of age were evaluable. Postvaccination HAI GMT ratios were equivalent for CAIV-T and LAIV. The GMT ratios of CAIV-T/LAIV for the H1N1, H3N2, and B strains were 1.24, 1.02, and 1.00, respectively, for the 5- to 8-year-old age group and 1.14, 1.12, and 0.96, respectively, for the 9- to 49-year-old age group. Seroresponse/seroconversion rates (fourfold or greater rise) were similar in both age groups for each of the three vaccine strains. Within 28 days, the most frequent reactogenicity event in the CAIV-T and LAIV groups was runny nose/nasal congestion, which occurred at higher rates after dose 1 (44% and 42%, respectively) than after dose 2 (41% and 29%, respectively) in the 5- to 8-year-old group. Otherwise, the rates of adverse events (AEs) were similar between the treatment groups and the two age cohorts, with no serious AEs related to the study vaccines. The immunogenicities, reactogenicity events, and AEs were comparable for refrigerated CAIV-T and frozen LAIV. PMID:17724151

  18. Clinical and serologic effects of live attenuated serum inhibitor-resistant influenza B vaccine in seronegative adults.

    PubMed

    Miller, L W; Togo, Y; Hornick, R B

    1977-01-01

    The clinical effects, nasal and serum antibody responses, and virus excretion of a live attenuated serum inhibitor-resistant influenza B virus vaccine, R75, was evaluated in 43 seronegative healthy adults by a random double-blind study. Symptom responses were minimal and were not significantly different between vaccine and placebo groups. No fevers, abnormalities in physical examination or laboratory testing developed during 4 weeks of observation. Among vaccinees, 10 (48%) developed serum hemagglutination-inhibition (HI) antibodies, 16 (76%) developed serum neutralization (N) antibodies and 4 (19%) developed nasal N antibodies. The GMT responses from study day 0 to day 28 were 4.0 to 10.4 for serum HI, 1.8 to 9.8 for serum N, and 1.0 to 1.4 for nasal N. There were no significant titer changes in the placebo group. No virus excretion was detected. Although there are some questions concerning the relationship of antibody levels to protection, the low antibody responses in this study are an indication that R75 is not sufficiently immunogenic.

  19. Mucosal vaccination with attenuated Mycobacterium tuberculosis induces strong central memory responses and protects against tuberculosis

    PubMed Central

    Kaushal, Deepak; Foreman, Taylor W.; Gautam, Uma S.; Alvarez, Xavier; Adekambi, Toidi; Rangel-Moreno, Javier; Golden, Nadia A.; Johnson, Ann-Marie F.; Phillips, Bonnie L.; Ahsan, Muhammad H.; Russell-Lodrigue, Kasi E.; Doyle, Lara A.; Roy, Chad J.; Didier, Peter J.; Blanchard, James L.; Rengarajan, Jyothi; Lackner, Andrew A.; Khader, Shabaana A.; Mehra, Smriti

    2015-01-01

    Tuberculosis (TB) is a global pandaemic, partially due to the failure of vaccination approaches. Novel anti-TB vaccines are therefore urgently required. Here we show that aerosol immunization of macaques with the Mtb mutant in SigH (MtbΔsigH) results in significant recruitment of inducible bronchus-associated lymphoid tissue (iBALT) as well as CD4+ and CD8+ T cells expressing activation and proliferation markers to the lungs. Further, the findings indicate that pulmonary vaccination with MtbΔsigH elicited strong central memory CD4+ and CD8+ T-cell responses in the lung. Vaccination with MtbΔsigH results in significant protection against a lethal TB challenge, as evidenced by an approximately three log reduction in bacterial burdens, significantly diminished clinical manifestations and granulomatous pathology and characterized by the presence of profound iBALT. This highly protective response is virtually absent in unvaccinated and BCG-vaccinated animals after challenge. These results suggest that future TB vaccine candidates can be developed on the basis of MtbΔsigH. PMID:26460802

  20. Development of a BCG challenge model for the testing of vaccine candidates against tuberculosis in cattle.

    PubMed

    Villarreal-Ramos, Bernardo; Berg, Stefan; Chamberlain, Laura; McShane, Helen; Hewinson, R Glyn; Clifford, Derek; Vordermeier, Martin

    2014-09-29

    Vaccination is being considered as part of a sustainable strategy for the control of bovine tuberculosis (BTB) in the UK. The live attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been used experimentally to vaccinate cattle against BTB. However, BCG confers partial protection against BTB and therefore, there is a need to develop improved vaccines. BTB vaccine efficacy experiments require the use of biosafety level 3 facilities which are expensive to maintain, generally oversubscribed and represent a bottle neck for the testing of vaccine candidates. One indicator of the induction of protective responses would be the ability of the host's immune response to control/kill mycobacteria. In this work we have evaluated an intranodal BCG challenge for the selection of vaccine candidates at biosafety level 2 which are capable of inducing mycobactericidal responses. To our knowledge, this is the first such report. Whilst BCG only confers partial protection, it is still the standard against which other vaccines are judged. Therefore we tested the BCG intranodal challenge in BCG (Danish strain) vaccinated cattle and showed that vaccinated cattle had lower BCG cfu counts than naïve cattle at 14 and 21 days after intranodal challenge with BCG (Tokyo strain). This model could help prioritize competing TB vaccine candidates and exploration of primary and secondary immune responses to mycobacteria.

  1. Recurrent 6th nerve palsy in a child following different live attenuated vaccines: case report

    PubMed Central

    2012-01-01

    Background Recurrent benign 6th nerve palsy in the paediatric age group is uncommon, but has been described following viral and bacterial infections. It has also been temporally associated with immunization, but has not been previously described following two different live attenuated vaccines. Case presentation A case is presented of a 12 month old Caucasian boy with recurrent benign 6th nerve palsy following measles-mumps-rubella and varicella vaccines, given on separate occasions with complete recovery following each episode. No alternate underlying etiology was identified despite extensive investigations and review. Conclusions The majority of benign 6th nerve palsies do not have a sinister cause and have an excellent prognosis, with recovery expected in most cases. The exact pathophysiology is unknown, although hypotheses including autoimmune mechanisms and direct viral invasion could explain the pathophysiology behind immunization related nerve palsies. It is important to rule out other aetiologies with thorough history, physical examination and investigations. There is limited information in the literature regarding the safety of a repeat dose of a live vaccine in this setting. Future immunizations should be considered on a case-by-case basis. PMID:22545865

  2. Genetic variation in vitro and in vivo of an attenuated Lassa vaccine candidate.

    PubMed

    Zapata, Juan C; Goicochea, Marco; Nadai, Yuka; Eyzaguirre, Lindsay M; Carr, Jean K; Tallon, Luke J; Sadzewicz, Lisa; Myers, Garry; Fraser, Claire M; Su, Qi; Djavani, Mahmoud; Lukashevich, Igor S; Salvato, Maria S

    2014-03-01

    The attenuated Lassa vaccine candidate ML29 is a laboratory-produced reassortant between Lassa and Mopeia viruses, two Old World arenaviruses that differ by 40% in nucleic acid sequence. In our previous studies, ML29 elicited sterilizing immunity against Lassa virus challenge in guinea pigs and marmosets and virus-specific cell-mediated immunity in both simian immunodeficiency virus (SIV)-infected and uninfected rhesus macaques. Here, we show that ML29 is stable after 12 passages in vitro without losing its plaque morphology or its attenuated phenotype in suckling mice. Additionally, we used deep sequencing to characterize the viral population comprising the original stock of ML29, the stock of ML29 after 12 passages in Vero cells, and the ML29 isolates obtained from vaccinated animals. Twenty-seven isolates bore approximately 77 mutations that exceeded 20% of the single-nucleotide polymorphism (SNP) changes at any single locus. Of these 77 mutations, 5 appeared to be host specific, for example, appearing in mice but not in primates. None of these mutations were reversions of ML29 to the sequences of the parental Lassa and Mopeia viruses. The host-specific mutations indicate viral adaptations to virus-host interactions, and such interactions make reasonable targets for antiviral approaches. Variants capable of chronic infection did not emerge from any of the primate infections, even in immune-deficient animals, indicating that the ML29 reassortant is reasonably stable in vivo. In conclusion, the preclinical studies of ML29 as a Lassa virus vaccine candidate have been advanced, showing high levels of protection in nonhuman primates and acceptable stability both in vitro and in vivo.

  3. [Antiviral vaccines].

    PubMed

    Girard, M

    1999-01-01

    Vaccination has been successful in controlling numerous diseases in man and animals. Smallpox has been eradicated and poliomyelitis is on the verge of being eradicated. The traditional immunization arsenal includes vaccines using live, attenuated, and inactivated organisms. DNA recombinant technology has added two new types of vaccines, i.e. subunit vaccines based on purified antigens produced by genetic engineering in bacterial, yeast, or animal-cell cultures and live recombinant vaccines based on attenuated bacterial or viral vectors. Currently the best known examples of these new vaccines are those using poxvirus vectors (vaccinia virus, canarypox virus, or fowlpox virus) but new vectors are under development. Another application for genetic engineering in the field of vaccinology is the development of DNA vaccines using naked plasmid DNA. This technique has achieved remarkable results in small rodents but its efficacy, safety, and feasibility in man has yet to be demonstrated. Numerous studies are now under way to improve the process. In the field of synthetic vaccines, lipopeptides have shown promise for induction of cell immune response. Development of vaccines for administration by the oral or nasal route may one day revolutionize vaccination techniques. However, effective vaccines against hepatitis C and HIV have stalled in the face of the complexity and pathophysiology of these diseases. These are the greatest challenges confronting scientists at the dawn of the new millennium.

  4. Development of a murine mycobacterial growth inhibition assay for evaluating vaccines against Mycobacterium tuberculosis.

    PubMed

    Parra, Marcela; Yang, Amy L; Lim, JaeHyun; Kolibab, Kristopher; Derrick, Steven; Cadieux, Nathalie; Perera, Liyanage P; Jacobs, William R; Brennan, Michael; Morris, Sheldon L

    2009-07-01

    The development and characterization of new tuberculosis (TB) vaccines has been impeded by the lack of reproducible and reliable in vitro assays for measuring vaccine activity. In this study, we developed a murine in vitro mycobacterial growth inhibition assay for evaluating TB vaccines that directly assesses the capacity of immune splenocytes to control the growth of Mycobacterium tuberculosis within infected macrophages. Using this in vitro assay, protective immune responses induced by immunization with five different types of TB vaccine preparations (Mycobacterium bovis BCG, an attenuated M. tuberculosis mutant strain, a DNA vaccine, a modified vaccinia virus strain Ankara [MVA] construct expressing four TB antigens, and a TB fusion protein formulated in adjuvant) can be detected. Importantly, the levels of vaccine-induced mycobacterial growth-inhibitory responses seen in vitro after 1 week of coculture correlated with the protective immune responses detected in vivo at 28 days postchallenge in a mouse model of pulmonary tuberculosis. In addition, similar patterns of cytokine expression were evoked at day 7 of the in vitro culture by immune splenocytes taken from animals immunized with the different TB vaccines. Among the consistently upregulated cytokines detected in the immune cocultures are gamma interferon, growth differentiation factor 15, interleukin-21 (IL-21), IL-27, and tumor necrosis factor alpha. Overall, we have developed an in vitro functional assay that may be useful for screening and comparing new TB vaccine preparations, investigating vaccine-induced protective mechanisms, and assessing manufacturing issues, including product potency and stability.

  5. The development and manufacture of influenza vaccines

    PubMed Central

    Buckland, Barry C

    2015-01-01

    The development and manufacture of an Influenza vaccine is unlike any other product in the Vaccine industry because of the need to change composition on a yearly basis. The poor efficacy of Influenza vaccines over the past 2 y in the Northern Hemisphere invites questions on how the vaccines are manufactured and how change in vaccine composition is controlled. The opinion expressed in this commentary is that the risk of not making the correct HA protein is increased by the need to adapt the new seasonal virus for good propagation in embryonated chicken eggs. This adaptation is required because not enough doses can be made in time for the new 'flu season unless productivity is reasonable. This problem is not necessarily solved by going to a cell culture host for virus propagation and that may explain why this more advanced technology approach is not more widely used. A vaccine based on hemagglutinin (HA) protein that does not involve Influenza virus propagation (such as Flublok®) side steps this particular problem. The exact HA sequence can be used as is in the virus. The technology can be run at large scale, already at 2 × 21,000L in Japan, in contrast to eggs where scale-up is by multiplication; the HA product is highly purified and made consistently in the form of rosettes. PMID:25844949

  6. Protection of Cattle against Rinderpest by Vaccination with Wild-Type but Not Attenuated Strains of Peste des Petits Ruminants Virus

    PubMed Central

    Holzer, Barbara; Hodgson, Sophia; Logan, Nicola; Willett, Brian

    2016-01-01

    ABSTRACT Although rinderpest virus (RPV) has been eradicated in the wild, efforts are still continuing to restrict the extent to which live virus is distributed in facilities around the world and to prepare for any reappearance of the disease, whether through deliberate or accidental release. In an effort to find an alternative vaccine which could be used in place of the traditional live attenuated RPV strains, we have determined whether cattle can be protected from rinderpest by inoculation with vaccine strains of the related morbillivirus, peste des petits ruminants virus (PPRV). Cattle were vaccinated with wild-type PPRV or either of two established PPRV vaccine strains, Nigeria/75/1 or Sungri/96. All animals developed antibody and T cell immune responses to the inoculated PPRV. However, only the animals given wild-type PPRV were protected from RPV challenge. Animals given PPRV/Sungri/96 were only partially protected, and animals given PPRV/Nigeria/75/1 showed no protection against RPV challenge. While sera from animals vaccinated with the vaccine strain of RPV showed cross-neutralizing ability against PPRV, none of the sera from animals vaccinated with any strain of PPRV was able to neutralize RPV although sera from animals inoculated with wild-type PPRV were able to neutralize RPV-pseudotyped vesicular stomatitis virus. IMPORTANCE Rinderpest virus has been eradicated, and it is only the second virus for which this is so. Significant efforts are still required to ensure preparedness for a possible escape of RPV from a laboratory or its deliberate release. Since RPV vaccine protects sheep and goats from PPRV, it is important to determine if the reverse is true as this would provide a non-RPV vaccine for dealing with suspected RPV outbreaks. This is probably the last in vivo study with live RPV that will be approved. PMID:26984722

  7. Live-Attenuated Bacterial Vectors: Tools for Vaccine and Therapeutic Agent Delivery

    PubMed Central

    Lin, Ivan Y. C.; Van, Thi Thu Hao; Smooker, Peter M.

    2015-01-01

    Genetically attenuated microorganisms, including pathogenic and commensal bacteria, can be engineered to carry and deliver heterologous antigens to elicit host immunity against both the vector as well as the pathogen from which the donor gene is derived. These live attenuated bacterial vectors have been given much attention due to their capacity to induce a broad range of immune responses including localized mucosal, as well as systemic humoral and/or cell-mediated immunity. In addition, the unique tumor-homing characteristics of these bacterial vectors has also been exploited for alternative anti-tumor vaccines and therapies. In such approach, tumor-associated antigen, immunostimulatory molecules, anti-tumor drugs, or nucleotides (DNA or RNA) are delivered. Different potential vectors are appropriate for specific applications, depending on their pathogenic routes. In this review, we survey and summarize the main features of the different types of live bacterial vectors and discussed the clinical applications in the field of vaccinology. In addition, different approaches for using live attenuated bacterial vectors for anti-cancer therapy is discussed, and some promising pre-clinical and clinical studies in this field are outlined. PMID:26569321

  8. Attenuated PfSPZ Vaccine induces strain-transcending T cells and durable protection against heterologous controlled human malaria infection.

    PubMed

    Lyke, Kirsten E; Ishizuka, Andrew S; Berry, Andrea A; Chakravarty, Sumana; DeZure, Adam; Enama, Mary E; James, Eric R; Billingsley, Peter F; Gunasekera, Anusha; Manoj, Anita; Li, Minglin; Ruben, Adam J; Li, Tao; Eappen, Abraham G; Stafford, Richard E; Kc, Natasha; Murshedkar, Tooba; Mendoza, Floreliz H; Gordon, Ingelise J; Zephir, Kathryn L; Holman, LaSonji A; Plummer, Sarah H; Hendel, Cynthia S; Novik, Laura; Costner, Pamela J M; Saunders, Jamie G; Berkowitz, Nina M; Flynn, Barbara J; Nason, Martha C; Garver, Lindsay S; Laurens, Matthew B; Plowe, Christopher V; Richie, Thomas L; Graham, Barney S; Roederer, Mario; Sim, B Kim Lee; Ledgerwood, Julie E; Hoffman, Stephen L; Seder, Robert A

    2017-02-21

    A live-attenuated malaria vaccine, Plasmodium falciparum sporozoite vaccine (PfSPZ Vaccine), confers sterile protection against controlled human malaria infection (CHMI) with Plasmodium falciparum (Pf) parasites homologous to the vaccine strain up to 14 mo after final vaccination. No injectable malaria vaccine has demonstrated long-term protection against CHMI using Pf parasites heterologous to the vaccine strain. Here, we conducted an open-label trial with PfSPZ Vaccine at a dose of 9.0 × 10(5) PfSPZ administered i.v. three times at 8-wk intervals to 15 malaria-naive adults. After CHMI with homologous Pf parasites 19 wk after final immunization, nine (64%) of 14 (95% CI, 35-87%) vaccinated volunteers remained without parasitemia compared with none of six nonvaccinated controls (P = 0.012). Of the nine nonparasitemic subjects, six underwent repeat CHMI with heterologous Pf7G8 parasites 33 wk after final immunization. Five (83%) of six (95% CI, 36-99%) remained without parasitemia compared with none of six nonvaccinated controls. PfSPZ-specific T-cell and antibody responses were detected in all vaccine recipients. Cytokine production by T cells from vaccinated subjects after in vitro stimulation with homologous (NF54) or heterologous (7G8) PfSPZ were highly correlated. Interestingly, PfSPZ-specific T-cell responses in the blood peaked after the first immunization and were not enhanced by subsequent immunizations. Collectively, these data suggest durable protection against homologous and heterologous Pf parasites can be achieved with PfSPZ Vaccine. Ongoing studies will determine whether protective efficacy can be enhanced by additional alterations in the vaccine dose and number of immunizations.

  9. The challenge of developing a herpes simplex virus 2 vaccine

    PubMed Central

    Dropulic, Lesia K; Cohen, Jeffrey I

    2013-01-01

    HSV infections are prevalent worldwide. A vaccine to prevent genital herpes would have a significant impact on this disease. Several vaccines have shown promise in animal models; however, so far these have not been successful in human clinical studies. Prophylactic HSV vaccines to prevent HSV infection or disease have focused primarily on eliciting antibody responses. Potent antibody responses are needed to result in sufficiently high levels of virus-specific antibody in the genital tract. Therapeutic vaccines that reduce recurrences need to induce potent T-cell responses at the site of infection. With the increasing incidence of HSV-1 genital herpes, an effective herpes vaccine should protect against both HSV-1 and HSV-2. Novel HSV vaccines, such as replication-defective or attenuated viruses, have elicited humoral and cellular immune responses in preclinical studies. These vaccines and others hold promise in future clinical studies. PMID:23252387

  10. Development of vaccines for Plasmodium vivax malaria.

    PubMed

    Mueller, Ivo; Shakri, Ahmad Rushdi; Chitnis, Chetan E

    2015-12-22

    Plasmodium vivax continues to cause significant morbidity outside Africa with more than 50% of malaria cases in many parts of South and South-east Asia, Pacific islands, Central and South America being attributed to P. vivax infections. The unique biology of P. vivax, including its ability to form latent hypnozoites that emerge months to years later to cause blood stage infections, early appearance of gametocytes before clinical symptoms are apparent and a shorter development cycle in the vector makes elimination of P. vivax using standard control tools difficult. The availability of an effective vaccine that provides protection and prevents transmission would be a valuable tool in efforts to eliminate P. vivax. Here, we review the latest developments related to P. vivax malaria vaccines and discuss the challenges as well as directions toward the goal of developing highly efficacious vaccines against P. vivax malaria.

  11. The expanding vaccine development pipeline, 1995-2008.

    PubMed

    Davis, Matthew M; Butchart, Amy T; Coleman, Margaret S; Singer, Dianne C; Wheeler, John R C; Pok, Angela; Freed, Gary L

    2010-02-03

    Successful launches of recently licensed vaccines contrast with pharmaceutical industry concerns about unfavorable market conditions, making the status and future of vaccine development uncertain. We assessed trends in private-sector vaccine research and development for the period 1995-2008, using a global pharmaceutical database to identify prophylactic vaccines in preclinical, Phase I, Phase II, or Phase III stages of development. We counted companies that research and/or manufacture vaccines ("vaccine originators") and their vaccine products in each year. The global number of vaccine originators doubled (to 136), as did the number of prophylactic vaccine products in development (to 354); the majority of this growth was in preclinical and early phase clinical research. Because rapid growth in earlier research phases has not yet led to growth in Phase III, it is not yet clear whether recent industry expansion will translate to an increase in the number of available vaccines in the near future.

  12. Further evaluation of a mutagen-attenuated Rift Valley fever vaccine in sheep.

    PubMed

    Morrill, J C; Carpenter, L; Taylor, D; Ramsburg, H H; Quance, J; Peters, C J

    1991-01-01

    A previous study demonstrated that a mutagen-attenuated Rift Valley fever virus (RVFV) vaccine, RVF MP-12, was immunogenic and non-abortogenic when ewes, 90-110 days pregnant, were inoculated with 5 x 10(5) plaque-forming units (p.f.u.) of the virus strain. The ewes delivered live, healthy lambs that had no neutralizing antibody to RVFV until after they had ingested colostrum. To assess further the safety and protective capability of this candidate vaccine, six pregnant ewes were inoculated with 5 x 10(3) p.f.u. of RVF MP-12 and challenged with 5 x 10(5) p.f.u. of virulent ZH-501 strain of RVFV 30 days later. No viraemia was detected after vaccination or challenge and all six ewes delivered live, healthy lambs. Those lambs tested before their nursing did not have neutralizing antibody to RVFV but quickly acquired antibody titres of 1:320 to greater than or equal to 1:10,240 after ingesting colostrum. To test the safety of the RVF MP-12 immunogen in neonates, lambs less than or equal to 7 days old, born to unvaccinated ewes, were inoculated with 5 x 10(5) p.f.u. of RVF MP-12. With the exception of brief pyrexia in 18 of 26 lambs, and a transient low-titred viraemia in 16 of 26 lambs after inoculation, no untoward effects were observed. Serum-neutralizing antibody to RVFV was detected 5-7 days after inoculation. Lambs vaccinated with either 5 x 10(5) or 5 x 10(3) p.f.u. of RVF MP-12 were protected against virulent RVFV challenge at 14 days postvaccination.

  13. Inactivation of SAM-methyltransferase is the mechanism of attenuation of a historic louse borne typhus vaccine strain.

    PubMed

    Liu, Yan; Wu, Bin; Weinstock, George; Walker, David H; Yu, Xue-Jie

    2014-01-01

    Louse borne typhus (also called epidemic typhus) was one of man's major scourges, and epidemics of the disease can be reignited when social, economic, or political systems are disrupted. The fear of a bioterrorist attack using the etiologic agent of typhus, Rickettsia prowazekii, was a reality. An attenuated typhus vaccine, R. prowazekii Madrid E strain, was observed to revert to virulence as demonstrated by isolation of the virulent revertant Evir strain from animals which were inoculated with Madrid E strain. The mechanism of the mutation in R. prowazekii that affects the virulence of the vaccine was not known. We sequenced the genome of the virulent revertant Evir strain and compared its genome sequence with the genome sequences of its parental strain, Madrid E. We found that only a single nucleotide in the entire genome was different between the vaccine strain Madrid E and its virulent revertant strain Evir. The mutation is a single nucleotide insertion in the methyltransferase gene (also known as PR028) in the vaccine strain that inactivated the gene. We also confirmed that the vaccine strain E did not cause fever in guinea pigs and the virulent revertant strain Evir caused fever in guinea pigs. We concluded that a single nucleotide insertion in the methyltransferase gene of R. prowazekii attenuated the R. prowazekii vaccine strain E. This suggested that an irreversible insertion or deletion mutation in the methyl transferase gene of R. prowazekii is required for Madrid E to be considered a safe vaccine.

  14. Safety and protective efficacy of a spiC and crp deletion mutant of Salmonella gallinarum as a live attenuated vaccine for fowl typhoid.

    PubMed

    Cheng, Zhao; Yin, Junlei; Kang, Xilong; Geng, Shizhong; Hu, Maozhi; Pan, Zhiming; Jiao, Xinan

    2016-08-01

    With an aim to develop a safe, immunogenic fowl typhoid (FT) vaccine, the safety and efficacy of 1009ΔspiCΔcrp, a spiC and crp deletion mutant of Salmonella gallinarum, were evaluated in chickens. Three-day-old chickens were intramuscularly immunized with 1009ΔspiCΔcrp (1×10(7)CFU) and boosted 7days later (at 10-days old) with the same dose and via the same route (vaccinated group). The vaccinated group showed no clinical symptoms and no differences in body weight compared to the unvaccinated control group. 1009ΔspiCΔcrp bacteria colonized and persisted in the liver and spleen of vaccinated chickens for >14days, and significant specific humoral and cellular immune responses were induced. Vaccinated chickens were challenged with S. gallinarum strain SG9 at 21days post-immunization (24-day-old chickens), and efficient protection was observed based on the mortality and clinical symptoms, as compared to those in the control group. These results demonstrate that 1009ΔspiCΔcrp can be used as a live attenuated vaccine.

  15. [Effect of Low Dose of Chicken Infectious Anemia Virus in Attenuated Vaccine on SPF Chicken Body Weight and Vaccine Immune Antibody].

    PubMed

    Fang, Lichun; Li, Xiaohan; Ren, Zhihao; Li, Yang; Wang, Yixin; Cui, Zhizhong; Chang, Shuang; Zhao, Peng

    2016-03-01

    In order to observe the effect of the immune and weight of chickens after use the attenuated vaccine with low dose of chicken infectious anemia virus (CIAV). In this study, the effects of low dose of CIAV on the weight of SPF chickens and NDV antibody production were observed by simulated experiments. The results showed that 10 EID50 and 5 EID50 CIAV per plume attenuated NDV vaccines were used to cause the weight loss of SPF chickens. Compared with the use of the non contaminated vaccine group, it has significant difference. And NDV antibody levels compared with the use of the non contaminated groups also decreased after use the vaccine with two doses of CIAV contaminated. It has significant difference. A certain proportion of CIAV antibody positive was detected at the beginning of the second week after use the NDV vaccine with two doses of CIAV contaminated. The detection of a high proportion of CIAV nucleic acid was detected in the first week after the use of a contaminated vaccine. The results of the study demonstrate the effects of CIAV pollution on the production and immune function of SPF chickens, and it is suggested that increasing the detection of viral nucleic acid can help save time and improve the detection rate in the detection of exogenous virus contamination by SPF chicken test method.

  16. Safety, dose, immunogenicity, and transmissibility of an oral live attenuated Shigella flexneri 2a vaccine candidate (SC602) among healthy adults and school children in Matlab, Bangladesh.

    PubMed

    Rahman, Kazi Mizanur; Arifeen, Shams El; Zaman, K; Rahman, Mahbubur; Raqib, Rubhana; Yunus, Mohammad; Begum, Nazma; Islam, Md Shaheenul; Sohel, Badrul Munir; Rahman, Muntasirur; Venkatesan, Malabi; Hale, Thomas L; Isenbarger, Daniel W; Sansonetti, Philippe J; Black, Robert E; Baqui, Abdullah H

    2011-02-01

    In double-blind trials in Bangladesh, 88 adults, and 79 children (8-10 years) were randomized to receive either a single oral dose of 1 × 10(4), 1 × 10(5) or 1 × 10(6)CFU of SC602 (a live, attenuated Shigella flexneri 2a strain vaccine) or placebo. In the adult outpatient 1 × 10(6) CFU group, severe joint pain and body aches were reported by one and two vaccinees respectively. In the adult inpatient trial, SC602 was isolated from 3 volunteers, pre-vaccination antibody titers were high, and fourfold increases in serum IgG anti-LPS responses were observed in 2 of 5 subjects of the 1 × 10(6)CFU group. None of the volunteers developed diarrhea. Overall, SC602 was found to be associated with minimal vaccine shedding, minimal reactogenicity, no transmission risk, and low immune stimulation.

  17. An attenuated virus vaccine appears safe to the central nervous system of rainbow trout (Oncorhynchus mykiss) after intranasal delivery

    PubMed Central

    Larragoite, Erin T.; Tacchi, Luca; LaPatra, Scott E.

    2016-01-01

    Nasal vaccines are very effective but the olfactory organ provides direct access of antigens to the brain. Infectious hematopoietic necrosis virus (IHNV) is known to cause high mortalities in salmonids. The purpose of this study is to evaluate the safety of a live attenuated IHNV nasal (I.N) vaccine in rainbow trout (Oncorhynchus mykiss). In the olfactory organ, the vaccine was detected 1 and 4 days after primary I.N vaccination but not in the intramuscular (i.m) or control groups. In the brain, IHNV was detected by RT-qPCR 4 and 21 days after i.m primary vaccination. One i.m and one I.N vaccinated trout were positive at days 4 and 28 days post-boost, respectively. Presence of IHNV in the brain of i.m vaccinated fish correlated with moderate increases in IL-1β and TNF-α expression in this tissue. These results demonstrate that IHNV vaccine lasts for 4 days in the local nasal environment and that nasal vaccination appears to be safe to the CNS of rainbow trout. PMID:26772477

  18. An attenuated virus vaccine appears safe to the central nervous system of rainbow trout (Oncorhynchus mykiss) after intranasal delivery.

    PubMed

    Larragoite, Erin T; Tacchi, Luca; LaPatra, Scott E; Salinas, Irene

    2016-02-01

    Nasal vaccines are very effective but the olfactory organ provides direct access of antigens to the brain. Infectious hematopoietic necrosis virus (IHNV) is known to cause high mortalities in salmonids. The purpose of this study is to evaluate the safety of a live attenuated IHNV nasal (I.N) vaccine in rainbow trout (Oncorhynchus mykiss). In the olfactory organ, the vaccine was detected 1 and 4 days after primary I.N vaccination but not in the intramuscular (i.m) or control groups. In the brain, IHNV was detected by RT-qPCR 4 and 21 days after i.m primary vaccination. One i.m and one I.N vaccinated trout were positive at days 4 and 28 days post-boost, respectively. Presence of IHNV in the brain of i.m vaccinated fish correlated with moderate increases in IL-1β and TNF-α expression in this tissue. These results demonstrate that IHNV vaccine lasts for 4 days in the local nasal environment and that nasal vaccination appears to be safe to the CNS of rainbow trout.

  19. Cellular and humoral immune responses and protection against schistosomes induced by a radiation-attenuated vaccine in chimpanzees.

    PubMed

    Eberl, M; Langermans, J A; Frost, P A; Vervenne, R A; van Dam, G J; Deelder, A M; Thomas, A W; Coulson, P S; Wilson, R A

    2001-09-01

    The radiation-attenuated Schistosoma mansoni vaccine is highly effective in rodents and primates but has never been tested in humans, primarily for safety reasons. To strengthen its status as a paradigm for a human recombinant antigen vaccine, we have undertaken a small-scale vaccination and challenge experiment in chimpanzees (Pan troglodytes). Immunological, clinical, and parasitological parameters were measured in three animals after multiple vaccinations, together with three controls, during the acute and chronic stages of challenge infection up to chemotherapeutic cure. Vaccination induced a strong in vitro proliferative response and early gamma interferon production, but type 2 cytokines were dominant by the time of challenge. The controls showed little response to challenge infection before the acute stage of the disease, initiated by egg deposition. In contrast, the responses of vaccinated animals were muted throughout the challenge period. Vaccination also induced parasite-specific immunoglobulin M (IgM) and IgG, which reached high levels at the time of challenge, while in control animals levels did not rise markedly before egg deposition. The protective effects of vaccination were manifested as an amelioration of acute disease and overall morbidity, revealed by differences in gamma-glutamyl transferase level, leukocytosis, eosinophilia, and hematocrit. Moreover, vaccinated chimpanzees had a 46% lower level of circulating cathodic antigen and a 38% reduction in fecal egg output, compared to controls, during the chronic phase of infection.

  20. Attenuated Salmonella Typhimurium delivery of a novel DNA vaccine induces immune responses and provides protection against duck enteritis virus.

    PubMed

    Liu, Xueyan; Liu, Qing; Xiao, Kangpeng; Li, Pei; Liu, Qiong; Zhao, Xinxin; Kong, Qingke

    2016-04-15

    DNA vaccines are widely used to prevent and treat infectious diseases, cancer and autoimmune diseases; however, their relatively low immunogenicity is an obstacle to their use. In this study, we constructed a novel and universal DNA vaccine vector (pSS898) that can be used to build DNA vaccines against duck enteritis virus (DEV) and other viruses that require DNA vaccines to provide protection. This vaccine vector has many advantages, including innate immunogenicity, efficient nuclear trafficking and resistance to attack from nucleases. UL24 and tgB from DEV were chosen as the antigens, and the heat labile enterotoxin B subunit (LTB) from Escherichia coli and the IL-2 gene (DuIL-2) from duck were used as adjuvants for the construction of DNA vaccine plasmids. Ducklings that were orally immunized with S739 (Salmonella Typhimurium Δasd-66 Δcrp-24 Δcya-25) and harboring these DEV DNA vaccines produced strong mucosal and systemic immune responses, and they resisted an otherwise lethal DEV challenge. More importantly, S739 (UL24-LTB) provided 90% protection after a priming-boost immunization. This study shows that our novel and universal DNA vaccine vector can be used efficiently in practical applications and may provide a promising method of orally inoculating ducks with a DEV DNA vaccine delivered by attenuated Salmonella Typhimurium for prevention of DVE.

  1. Development of Dengue Vaccine, Phase 1

    DTIC Science & Technology

    1987-07-01

    AD-A260 281 AD____ CONTRACT NO: DAMD17-87-C-7061 D TIC([%ELECTE TITLE: DEVELOPMENT OF DENGUE VACCINE, PHASE I S 6 PRINCIPAL INVESTIGATOR: John M. Ivy...Phase I (12/15/86-6/15/871 J- " , : T.5 5 JNDOZG :;UMBERS Contract No. Development of Dengue Vaccine, Phase I DAMD17-87-C-7061 65502A 13P665502M802.AA...distribution unlimited Dengue virus is a mosquito borne, positive strand RNA virus responsi- ble for hundreds of thousands of illnesses annually. No

  2. Recent vaccine development for human metapneumovirus

    PubMed Central

    Ren, J.; Phan, T.

    2015-01-01

    Human metapneumovirus (hMPV) and respiratory syncytial virus, its close family member, are two major causes of lower respiratory tract infection in the paediatric population. hMPV is also a common cause of worldwide morbidity and mortality in immunocompromised patients and older adults. Repeated infections occur often, demonstrating a heavy medical burden. However, there is currently no hMPV-specific prevention treatment. This review focuses on the current literature on hMPV vaccine development. We believe that a better understanding of the role(s) of viral proteins in host responses might lead to efficient prophylactic vaccine development. PMID:25667325

  3. Recombinant mouse cytomegalovirus expressing a ligand for the NKG2D receptor is attenuated and has improved vaccine properties

    PubMed Central

    Slavuljica, Irena; Busche, Andreas; Babić, Marina; Mitrović, Maja; Gašparović, Iva; Cekinović, Đurđica; Markova Car, Elitza; Pernjak Pugel, Ester; Ciković, Ana; Lisnić, Vanda Juranić; Britt, William J.; Koszinowski, Ulrich; Messerle, Martin; Krmpotić, Astrid; Jonjić, Stipan

    2010-01-01

    Human CMV (HCMV) is a major cause of morbidity and mortality in both congenitally infected and immunocompromised individuals. Development of an effective HCMV vaccine would help protect these vulnerable groups. NK group 2, member D (NKG2D) is a potent activating receptor expressed by cells of the innate and adaptive immune systems. Its importance in HCMV immune surveillance is indicated by the elaborative evasion mechanisms evolved by the virus to avoid NKG2D. In order to study this signaling pathway, we engineered a recombinant mouse CMV expressing the high-affinity NKG2D ligand RAE-1γ (RAE-1γMCMV). Expression of RAE-1γ by MCMV resulted in profound virus attenuation in vivo and lower latent viral DNA loads. RAE-1γMCMV infection was efficiently controlled by immunodeficient hosts, including mice lacking type I interferon receptors or immunosuppressed by sublethal γ-irradiation. Features of MCMV infection in neonates were also diminished. Despite tight innate immune control, RAE-1γMCMV infection elicited strong and long-lasting protective immunity. Maternal RAE-1γMCMV immunization protected neonatal mice from MCMV disease via placental transfer of antiviral Abs. Despite strong selective pressure, the RAE-1γ transgene did not exhibit sequence variation following infection. Together, our results indicate that use of a recombinant virus encoding the ligand for an activating NK cell receptor could be a powerful approach to developing a safe and immunogenic HCMV vaccine. PMID:21099111

  4. Divergent immune responses and disease outcomes in piglets immunized with inactivated and attenuated H3N2 swine influenza vaccines in the presence of maternally-derived antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine-associated enhanced respiratory disease (VAERD) can occur in pigs immunized with whole-inactivated influenza virus (WIV) vaccine and subsequently infected with an antigenically divergent virus of the same HA subtype. Live-attenuated influenza virus (LAIV) vaccines administered intranasally h...

  5. Vaccine development for emerging virulent infectious diseases.

    PubMed

    Maslow, Joel N

    2017-02-16

    The recent outbreak of Zaire Ebola virus in West Africa altered the classical paradigm of vaccine development and that for emerging infectious diseases (EIDs) in general. In this paper, the precepts of vaccine discovery and advancement through pre-clinical and clinical assessment are discussed in the context of the recent Ebola virus, Middle East Respiratory Syndrome coronavirus (MERS-CoV), and Zika virus outbreaks. Clinical trial design for diseases with high mortality rates and/or high morbidity in the face of a global perception of immediate need and the factors that drive design in the face of a changing epidemiology are presented. Vaccines for EIDs thus present a unique paradigm to standard development precepts.

  6. Development of Vaccines against Visceral Leishmaniasis

    PubMed Central

    Evans, Krystal J.; Kedzierski, Lukasz

    2012-01-01

    Leishmaniasis is a neglected disease resulting in a global morbidity of 2,090 thousand Disability-Adjusted Life Years and a mortality rate of approximately 60,000 per year. Among the three clinical forms of leishmaniasis (cutaneous, mucosal, and visceral), visceral leishmaniasis (VL) accounts for the majority of mortality, as if left untreated VL is almost always fatal. Caused by infection with Leishmania donovani or L. infantum, VL represents a serious public health problem in endemic regions and is rapidly emerging as an opportunistic infection in HIV patients. To date, no vaccine exists for VL or any other form of leishmaniasis. In endemic areas, the majority of those infected do not develop clinical symptoms and past infection leads to robust immunity against reinfection. Thus the development of vaccine for Leishmania is a realistic public health goal, and this paper summarizes advances in vaccination strategies against VL. PMID:21912561

  7. Development of prophylactic vaccines against HIV-1.

    PubMed

    Schiffner, Torben; Sattentau, Quentin J; Dorrell, Lucy

    2013-07-17

    The focus of most current HIV-1 vaccine development is on antibody-based approaches. This is because certain antibody responses correlated with protection from HIV-1 acquisition in the RV144 phase III trial, and because a series of potent and broad spectrum neutralizing antibodies have been isolated from infected individuals. Taken together, these two findings suggest ways forward to develop a neutralizing antibody-based vaccine. However, understanding of the correlates of protection from disease in HIV-1 and other infections strongly suggests that we should not ignore CTL-based research. Here we review recent progress in the field and highlight the challenges implicit in HIV-1 vaccine design and some potential solutions.

  8. CD8+ T-cell Responses in Flavivirus-Naive Individuals Following Immunization with a Live-Attenuated Tetravalent Dengue Vaccine Candidate.

    PubMed

    Chu, Haiyan; George, Sarah L; Stinchcomb, Dan T; Osorio, Jorge E; Partidos, Charalambos D

    2015-11-15

    We are developing a live-attenuated tetravalent dengue vaccine (TDV) candidate based on an attenuated dengue 2 virus (TDV-2) and 3 chimeric viruses containing the premembrane and envelope genes of dengue viruses (DENVs) -1, -3, and -4 expressed in the context of the attenuated TDV-2 genome (TDV-1, TDV-3, and TDV-4, respectively). In this study, we analyzed and characterized the CD8(+) T-cell response in flavivirus-naive human volunteers vaccinated with 2 doses of TDV 90 days apart via the subcutaneous or intradermal routes. Using peptide arrays and intracellular cytokine staining, we demonstrated that TDV elicits CD8(+) T cells targeting the nonstructural NS1, NS3, and NS5 proteins of TDV-2. The cells were characterized by the production of interferon-γ, tumor necrosis factor-α, and to a lesser extent interleukin-2. Responses were highest on day 90 after the first dose and were still detectable on 180 days after the second dose. In addition, CD8(+) T cells were multifunctional, producing ≥2 cytokines simultaneously, and cross-reactive to NS proteins of the other 3 DENV serotypes. Overall, these findings describe the capacity of our candidate dengue vaccine to elicit cellular immune responses and support the further evaluation of T-cell responses in samples from future TDV clinical trials.

  9. Protection induced by commercially available live-attenuated and recombinant viral vector vaccines against infectious laryngotracheitis virus in broiler chickens.

    PubMed

    Vagnozzi, Ariel; Zavala, Guillermo; Riblet, Sylva M; Mundt, Alice; García, Maricarmen

    2012-01-01

    Viral vector vaccines using fowl poxvirus (FPV) and herpesvirus of turkey (HVT) as vectors and carrying infectious laryngotracheitis virus (ILTV) genes are commercially available to the poultry industry in the USA. Different sectors of the broiler industry have used these vaccines in ovo or subcutaneously, achieving variable results. The objective of the present study was to determine the efficacy of protection induced by viral vector vaccines as compared with live-attenuated ILTV vaccines. The HVT-LT vaccine was more effective than the FPV-LT vaccine in mitigating the disease and reducing levels of challenge virus when applied in ovo or subcutaneously, particularly when the challenge was performed at 57 days rather than 35 days of age. While the FPV-LT vaccine mitigated clinical signs more effectively when administered subcutaneously than in ovo, it did not reduce the concentration of challenge virus in the trachea by either application route. Detection of antibodies against ILTV glycoproteins expressed by the viral vectors was a useful criterion to assess the immunogenicity of the vectors. The presence of glycoprotein I antibodies detected pre-challenge and post challenge in chickens vaccinated with HVT-LT indicated that the vaccine induced a robust antibody response, which was paralleled by significant reduction of clinical signs. The chicken embryo origin vaccine provided optimal protection by significantly mitigating the disease and reducing the challenge virus in chickens vaccinated via eye drop. The viral vector vaccines, applied in ovo and subcutaneously, provided partial protection, reducing to some degree clinical signs, and challenge VIRUS replication in the trachea.

  10. Elucidation of the molecular basis for the attenuation of a live, attenuated influenza A H5N1 cold-adapted vaccine virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recombinant, live influenza A H5N1 vaccine candidate with the hemagglutinin (HA) and neuraminidase (NA) genes derived from A/VietNam/1203/04 (H5N1) (H5N1 2004 wt) and the internal protein genes from A/Ann Arbor/6/60 (AA) (H2N2) cold-adapted (ca) virus has been previously shown to be attenuated in ...

  11. Subviral Particle as Vaccine and Vaccine Platform

    PubMed Central

    Tan, Ming; Jiang, Xi

    2014-01-01

    Recombinant subvirual particles retain similar antigenic features of their authentic viral capsids and thus have been applied as nonreplicating subunit vaccines against viral infection and illness. Additionally, the self-assembled, polyvalent subviral particles are excellent platforms to display foreign antigens for immune enhancement for vaccine development. These subviral particle-based vaccines are noninfectious and thus safer than the conventional live attenuated and inactivated vaccines. While several VLP vaccines are available in the markets, numerous others, including dual vaccines against more than one pathogen, are under clinical or preclinical development. This article provides an update of these efforts. PMID:24662314

  12. A reassortment-incompetent live attenuated influenza virus vaccine for use in protection against pandemic virus strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although live-attenuated influenza vaccines (LAIV) are safe for use in protection against seasonal influenza strains, concerns over their potential to reassort with wild-type virus strains have been voiced. LAIVs have been demonstrated to induce enhanced mucosal and cell-mediated immunity over inac...

  13. Impact of BRICS' investment in vaccine development on the global vaccine market.

    PubMed

    Kaddar, Miloud; Milstien, Julie; Schmitt, Sarah

    2014-06-01

    Brazil, the Russian Federation, India, China and South Africa--the countries known as BRICS--have made considerable progress in vaccine production, regulation and development over the past 20 years. In 1993, all five countries were producing vaccines but the processes used were outdated and non-standardized, there was little relevant research and there was negligible international recognition of the products. By 2014, all five countries had strong initiatives for the development of vaccine technology and had greatly improved their national regulatory capacity. South Africa was then the only BRICS country that was not completely producing vaccines. South Africa is now in the process of re-establishing its own vaccine production and passing beyond the stage of simply importing, formulating and filling vaccine bulks. Changes in the public sector's price per dose of selected vaccines, the global market share represented by products from specific manufacturers, and the attractiveness, for multinational companies, of partnership and investment opportunities in BRICS companies have all been analysed. The results indicate that the BRICS countries have had a major impact on vaccine price and availability, with much of that impact attributable to the output of Indian vaccine manufacturers. China is expected to have a greater impact soon, given the anticipated development of Chinese vaccine manufacturers in the near future. BRICS' accomplishments in the field of vaccine development are expected to reshape the global vaccine market and accelerate access to vaccines in the developing world. The challenge is to turn these expectations into strategic actions and practical outcomes.

  14. Pre- and post-exposure safety and efficacy of attenuated rabies virus vaccines are enhanced by their expression of IFNγ

    SciTech Connect

    Barkhouse, Darryll A.; Faber, Milosz; Hooper, D. Craig

    2015-01-01

    Consistent with evidence of a strong correlation between interferon gamma (IFNγ) production and rabies virus (RABV) clearance from the CNS, we recently demonstrated that engineering a pathogenic RABV to express IFNγ highly attenuates the virus. Reasoning that IFNγ expression by RABV vaccines would enhance their safety and efficacy, we reverse-engineered two proven vaccine vectors, GAS and GASGAS, to express murine IFNγ. Mortality and morbidity were monitored during suckling mice infection, immunize/challenge experiments and mixed intracranial infections. We demonstrate that GASγ and GASγGAS are significantly attenuated in suckling mice compared to the GASGAS vaccine. GASγ better protects mice from lethal DRV4 RABV infection in both pre- and post-exposure experiments compared to GASGAS. Finally, GASγGAS reduces post-infection neurological sequelae, compared to control, during mixed intracranial infection with DRV4. These data show IFNγ expression by a vaccine vector can enhance its safety while increasing its efficacy as pre- and post-exposure treatment. - Highlights: • IFNγ expression improves attenuated rabies virus safety and immunogenicity. • IFNγ expression is safer and more immunogenic than doubling glycoprotein expression. • Co-infection with IFNγ-expressing RABV prevents wild-type rabies virus lethality. • Vaccine safety and efficacy is additive for IFNγ and double glycoprotein expression.

  15. Evaluating the effectiveness, impact and safety of live attenuated and seasonal inactivated influenza vaccination: protocol for the Seasonal Influenza Vaccination Effectiveness II (SIVE II) study

    PubMed Central

    Lone, Nazir I; Kavanagh, Kimberley; Robertson, Chris; McMenamin, Jim; von Wissmann, Beatrix; Vasileiou, Eleftheria; Butler, Chris; Ritchie, Lewis D; Gunson, Rory; Schwarze, Jürgen; Sheikh, Aziz

    2017-01-01

    Introduction Seasonal (inactivated) influenza vaccination is recommended for all individuals aged 65+ and in individuals under 65 who are at an increased risk of complications of influenza infection, for example, people with asthma. Live attenuated influenza vaccine (LAIV) was recommended for children as they are thought to be responsible for much of the transmission of influenza to the populations at risk of serious complications from influenza. A phased roll-out of the LAIV pilot programme began in 2013/2014. There is limited evidence for vaccine effectiveness (VE) in the populations targeted for influenza vaccination. The aim of this study is to examine the safety and effectiveness of the live attenuated seasonal influenza vaccine programme in children and the inactivated seasonal influenza vaccination programme among different age and at-risk groups of people. Methods and analysis Test negative and cohort study designs will be used to estimate VE. A primary care database covering 1.25 million people in Scotland for the period 2000/2001 to 2015/2016 will be linked to the Scottish Immunisation Recall Service (SIRS), Health Protection Scotland virology database, admissions to Scottish hospitals and the Scottish death register. Vaccination status (including LAIV uptake) will be determined from the primary care and SIRS database. The primary outcome will be influenza-positive real-time PCR tests carried out in sentinel general practices and other healthcare settings. Secondary outcomes include influenza-like illness and asthma-related general practice consultations, hospitalisations and death. An instrumental variable analysis will be carried out to account for confounding. Self-controlled study designs will be used to estimate the risk of adverse events associated with influenza vaccination. Ethics and dissemination We obtained approval from the National Research Ethics Service Committee, West Midlands—Edgbaston. The study findings will be presented at

  16. Protein Crystallography in Vaccine Research and Development

    PubMed Central

    Malito, Enrico; Carfi, Andrea; Bottomley, Matthew J.

    2015-01-01

    The use of protein X-ray crystallography for structure-based design of small-molecule drugs is well-documented and includes several notable success stories. However, it is less well-known that structural biology has emerged as a major tool for the design of novel vaccine antigens. Here, we review the important contributions that protein crystallography has made so far to vaccine research and development. We discuss several examples of the crystallographic characterization of vaccine antigen structures, alone or in complexes with ligands or receptors. We cover the critical role of high-resolution epitope mapping by reviewing structures of complexes between antigens and their cognate neutralizing, or protective, antibody fragments. Most importantly, we provide recent examples where structural insights obtained via protein crystallography have been used to design novel optimized vaccine antigens. This review aims to illustrate the value of protein crystallography in the emerging discipline of structural vaccinology and its impact on the rational design of vaccines. PMID:26068237

  17. Mycoplasma hyopneumoniae: from disease to vaccine development.

    PubMed

    Simionatto, Simone; Marchioro, Silvana Beutinger; Maes, Dominiek; Dellagostin, Odir Antônio

    2013-08-30

    Mycoplasma hyopneumoniae is the etiological agent of swine enzootic pneumonia (EP), a disease that affects swine production worldwide. Vaccination is the most cost-effective strategy for the control and prevention of the disease. Despite efforts to control M. hyopneumoniae infection, significant economic losses in pig production continue to occur. The results of genome-based research have the potential to help understand the biology and pathogenesis of M. hyopneumoniae, and contribute to the development of more effective vaccines and diagnostic tests. In this review, the characteristics of M. hyopneumoniae related to pathogenesis and control measures will be discussed. Special emphasis will be placed on vaccination strategies that have been proposed with the use of reverse vaccinology approaches.

  18. Attenuation and efficacy of human parainfluenza virus type 1 (HPIV1) vaccine candidates containing stabilized mutations in the P/C and L genes

    PubMed Central

    Bartlett, Emmalene J; Castaño, Adam; Surman, Sonja R; Collins, Peter L; Skiadopoulos, Mario H; Murphy, Brian R

    2007-01-01

    Background Two recombinant, live attenuated human parainfluenza virus type 1 (rHPIV1) mutant viruses have been developed, using a reverse genetics system, for evaluation as potential intranasal vaccine candidates. These rHPIV1 vaccine candidates have two non-temperature sensitive (non-ts) attenuating (att) mutations primarily in the P/C gene, namely CR84GHNT553A (two point mutations used together as a set) and CΔ170 (a short deletion mutation), and two ts att mutations in the L gene, namely LY942A (a point mutation), and LΔ1710–11 (a short deletion), the last of which has not been previously described. The latter three mutations were specifically designed for increased genetic and phenotypic stability. These mutations were evaluated on the HPIV1 backbone, both individually and in combination, for attenuation, immunogenicity, and protective efficacy in African green monkeys (AGMs). Results The rHPIV1 mutant bearing the novel LΔ1710–11 mutation was highly ts and attenuated in AGMs and was immunogenic and efficacious against HPIV1 wt challenge. The rHPIV1-CR84G/Δ170HNT553ALY942A and rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 vaccine candidates were highly ts, with shut-off temperatures of 38°C and 35°C, respectively, and were highly attenuated in AGMs. Immunization with rHPIV1-CR84G/Δ170HNT553ALY942A protected against HPIV1 wt challenge in both the upper and lower respiratory tracts. In contrast, rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 was not protective in AGMs due to over-attenuation, but it is expected to replicate more efficiently and be more immunogenic in the natural human host. Conclusion The rHPIV1-CR84G/Δ170HNT553ALY942A and rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 vaccine candidates are clearly highly attenuated in AGMs and clinical trials are planned to address safety and immunogenicity in humans. PMID:17605811

  19. Nontyphoidal salmonella disease: Current status of vaccine research and development.

    PubMed

    Tennant, Sharon M; MacLennan, Calman A; Simon, Raphael; Martin, Laura B; Khan, M Imran

    2016-06-03

    Among more than 2500 nontyphoidal Salmonella enterica (NTS) serovars, S. enterica serovar Typhimurium and S. enterica serovar Enteritidis account for approximately fifty percent of all human isolates of NTS reported globally. The global incidence of NTS gastroenteritis in 2010 was estimated to be 93 million cases, approximately 80 million of which were contracted via food-borne transmission. It is estimated that 155,000 deaths resulted from NTS in 2010. NTS also causes severe, extra-intestinal, invasive bacteremia, referred to as invasive nontyphoidal Salmonella (iNTS) disease. iNTS disease usually presents as a febrile illness, frequently without gastrointestinal symptoms, in both adults and children. Symptoms of iNTS are similar to malaria, often including fever (>90%) and splenomegaly (>40%). The underlying reasons for the high rates of iNTS disease in Africa are still being elucidated. Evidence from animal and human studies supports the feasibility of developing a safe and effective vaccine against iNTS. Both antibodies and complement can kill Salmonella species in vitro. Proof-of-principle studies in animal models have demonstrated efficacy for live attenuated and subunit vaccines that target the O-antigens, flagellin proteins, and other outer membrane proteins of serovars Typhimurium and Enteritidis. More recently, a novel delivery strategy for NTS vaccines has been developed: the Generalized Modules for Membrane Antigens (GMMA) technology which presents surface polysaccharides and outer membrane proteins in their native conformation. GMMA technology is self-adjuvanting, as it delivers multiple pathogen-associated molecular pattern molecules. GMMA may be particularly relevant for low- and middle-income countries as it has the potential for high immunologic potency at a low cost and involves a relatively simple production process without the need for complex conjugation. Several vaccines for the predominant NTS serovars Typhimurium and Enteritidis, are

  20. Development of Recombinant Measles Virus-Based Vaccines.

    PubMed

    Mühlebach, Michael D; Hutzler, Stefan

    2017-01-01

    This chapter describes the development of recombinant measles virus (MV)-based vaccines starting from plasmid DNA. Live-attenuated measles vaccines are very efficient and safe. Since the availability of a reverse genetic system to manipulate MV genomes and to generate respective recombinant viruses, a considerable number of recombinant viruses has been generated that present antigens of foreign pathogens during MV replication. Thereby, robust humoral and cellular immune responses can be induced, which have shown protective capacity in a substantial number of experiments.For this purpose, the foreign antigen-encoding genes are cloned into additional transcription units of plasmid based full-length MV vaccine strain genomes, which in turn are used to rescue recombinant MV by providing both full-length viral RNA genomes respective anti-genomes together with all protein components of the viral ribonucleoprotein complex after transient transfection of the so-called rescue cells. Infectious centers form among these transfected cells, which allow clonal isolation of single recombinant viruses that are subsequently amplified, characterized in vitro, and then evaluated for their immunogenicity in appropriate preclinical animal models.

  1. Methods and Protocols for Developing Prion Vaccines.

    PubMed

    Marciniuk, Kristen; Taschuk, Ryan; Napper, Scott

    2016-01-01

    Prion diseases denote a distinct form of infectivity that is based in the misfolding of a self-protein (PrP(C)) into a pathological, infectious conformation (PrP(Sc)). Efforts to develop vaccines for prion diseases have been complicated by the potential dangers that are associated with induction of immune responses against a self-protein. As a consequence, there is considerable appeal for vaccines that specifically target the misfolded prion conformation. Such conformation-specific immunotherapy is made possible through the identification of vaccine targets (epitopes) that are exclusively presented as a consequence of misfolding. An immune response directed against these targets, termed disease-specific epitopes (DSEs), has the potential to spare the function of the native form of the protein while clearing, or neutralizing, the infectious isomer. Although identification of DSEs represents a critical first step in the induction of conformation-specific immune responses, substantial efforts are required to translate these targets into functional vaccines. Due to the poor immunogenicity that is inherent to self-proteins, and that is often associated with short peptides, substantial efforts are required to overcome tolerance-to-self and maximize the resultant immune response following DSE-based immunization. This often includes optimization of target sequences in terms of immunogenicity and development of effective formulation and delivery strategies for the associated peptides. Further, these vaccines must satisfy additional criteria from perspectives of specificity (PrP(C) vs. PrP(Sc)) and safety (antibody-induced template-driven misfolding of PrP(C)). The emphasis of this report is on the steps required to translate DSEs into prion vaccines and subsequent evaluation of the resulting immune responses.

  2. Mucosal and systemic immunization with a novel attenuated pneumococcal vaccine candidate confer serotype independent protection against Streptococcus pneumoniae in mice.

    PubMed

    Wu, Kaifeng; Yao, Run; Wang, Hong; Pang, Dan; Liu, Yusi; Xu, Hongmei; Zhang, Shuai; Zhang, Xuemei; Yin, Yibing

    2014-07-16

    Despite the availability of effective vaccines, Streptococcus pneumoniae is still one of the major infectious diseases causing substantial morbidity and mortality in children under 5 years old. In this study, we demonstrate the protective efficacy of S. pneumoniae SPY1, a novel live attenuated vaccine strain against pneumococcal infection in murine models. This strain was characterized by defects in three important pneumococcal virulence factors including capsule, teichoic acids and pneumolysin. The lactate dehydrogenase assays and in vivo animal experiments demonstrated a significantly attenuated virulence and a reduced nasopharyngeal colonization for the SPY1 strain. We also show that mucosal and systemic immunization with the live SPY1 strain induced protective immune responses against pneumococci. Mucosal immunization with SPY1 offered better protection against colonization challenge with strains TIGR4 and serotype 19F than systemic SPY1 immunization. In invasive infection models, mucosal vaccination with the SPY1 strain conferred complete protection against D39 and clinical serotype 6B and 3 strains. Notably, intranasal vaccination with the SPY1 strain conferred superior protection against pneumococcal invasive disease compared with the commercial available vaccines. SPY1 strain was shown to elicit high levels of serotype-independent antibodies and a mixed cellular immune response. Besides, the SPY1 serum was able to passively protect mice against invasive challenge with D39 strain, indicating the protective effect of the antibody-mediated responses. Together, the SPY1 strain may be a promising live vaccine strain to protect pneumococcal infection.

  3. The Human CD8+ T Cell Responses Induced by a Live Attenuated Tetravalent Dengue Vaccine Are Directed against Highly Conserved Epitopes

    PubMed Central

    Angelo, Michael A.; Bangs, Derek J.; Sidney, John; Paul, Sinu; Peters, Bjoern; de Silva, Aruna D.; Lindow, Janet C.; Diehl, Sean A.; Whitehead, Stephen; Durbin, Anna; Kirkpatrick, Beth; Sette, Alessandro

    2014-01-01

    ABSTRACT The incidence of infection with any of the four dengue virus serotypes (DENV1 to -4) has increased dramatically in the last few decades, and the lack of a treatment or vaccine has contributed to significant morbidity and mortality worldwide. A recent comprehensive analysis of the human T cell response against wild-type DENV suggested an human lymphocyte antigen (HLA)-linked protective role for CD8+ T cells. We have collected one-unit blood donations from study participants receiving the monovalent or tetravalent live attenuated DENV vaccine (DLAV), developed by the U.S. National Institutes of Health. Peripheral blood mononuclear cells from these donors were screened in gamma interferon enzyme-linked immunosorbent spot assays with pools of predicted, HLA-matched, class I binding peptides covering the entire DENV proteome. Here, we characterize for the first time CD8+ T cell responses after live attenuated dengue vaccination and show that CD8+ T cell responses in vaccinees were readily detectable and comparable to natural dengue infection. Interestingly, whereas broad responses to structural and nonstructural (NS) proteins were observed after monovalent vaccination, T cell responses following tetravalent vaccination were, dramatically, focused toward the highly conserved NS proteins. Epitopes were highly conserved in a vast variety of field isolates and able to elicit multifunctional T cell responses. Detailed knowledge of the T cell response will contribute to the identification of robust correlates of protection in natural immunity and following vaccination against DENV. IMPORTANCE The development of effective vaccination strategies against dengue virus (DENV) infection and clinically significant disease is a task of high global public health value and significance, while also being a challenge of significant complexity. A recent efficacy trial of the most advanced dengue vaccine candidate, demonstrated only partial protection against all four DENV

  4. Eliciting neutralizing antibodies against the membrane proximal external region of HIV-1 Env by chimeric live attenuated influenza A virus vaccines.

    PubMed

    Zang, Yang; Du, Dongchuan; Li, Na; Su, Weiheng; Liu, Xintao; Zhang, Yan; Nie, Jianhui; Wang, Youchun; Kong, Wei; Jiang, Chunlai

    2015-07-31

    Despite significant efforts directed toward research on HIV-1 vaccines, a truly effective immunogen has not been achieved. However, the broadly neutralizing antibodies (BnAbs) 2F5 and 4E10, targeting the highly conserved membrane proximal external region (MPER) of HIV-1, are two promising tools for vaccine development. Here we engrafted the MPER into the linker domain between the trimeric core structure and the transmembrane domain of influenza A virus HA2 to investigate the potential of such chimeric viruses to elicit HIV-1 neutralizing antibodies. In the context of proliferating attenuated influenza A viruses, these HIV-1 neutralizing antibody epitopes could be continuously expressed and mimicked their native conformation to induce humoral immune responses. While MPER-specific antibodies could be detected in serum of guinea pigs vaccinated with the chimeric viruses, they exhibited only weakly neutralizing activities. These antisera from vaccinated animals neutralized viruses of clades B and BC (tier 1), but not of clades AE (tier 1) and C (tier 2). These results suggest that influenza A virus can be used as a vehicle for displaying MPER and inducing BnAbs, but it provides limited protection against HIV-1 infection. In the future development of HIV-1 vaccines by rational design, a more effective live virus vector or multiple antigens should be chosen to facilitate the process of neutralizing antibody maturation.

  5. Status of vaccine research and development of vaccines for Chlamydia trachomatis infection.

    PubMed

    Poston, Taylor B; Gottlieb, Sami L; Darville, Toni

    2017-01-19

    Genital infection with Chlamydia trachomatis, a gram-negative obligate intracellular bacterium, is the most common bacterial sexually transmitted infection globally. Ascension of chlamydial infection to the female upper genital tract can cause acute pelvic inflammatory disease, tubal factor infertility, ectopic pregnancy, and chronic pelvic pain. Shortcomings of current chlamydia control strategies, especially for low- and middle-income countries, highlight the need for an effective vaccine. Evidence from animal models, human epidemiological studies, and early trachoma vaccine trials suggest that a C. trachomatis vaccine is feasible. Vaccine development for genital chlamydial infection has been in the preclinical phase of testing for many years, but the first Phase I trials of chlamydial vaccine candidates are underway, and scientific advances hold promise for additional candidates to enter clinical evaluation in the coming years. We describe the clinical and public health need for a C. trachomatis vaccine, provide an overview of Chlamydia vaccine development efforts, and summarize current vaccine candidates in the development pipeline.

  6. Tuberculosis vaccines--state of the art, and novel approaches to vaccine development.

    PubMed

    da Costa, Christopher; Walker, Barry; Bonavia, Aurelio

    2015-03-01

    The quest for a vaccine that could have a major impact in reducing the current global burden of TB disease in humans continues to be extremely challenging. Significant gaps in our knowledge and understanding of the pathogenesis and immunology of tuberculosis continue to undermine efforts to break new ground, and traditional approaches to vaccine development have thus far met with limited success. Existing and novel candidate vaccines are being assessed in the context of their ability to impact the various stages that culminate in disease transmission and an increase in the global burden of disease. Innovative methods of vaccine administration and delivery have provided a fresh stimulus to the search for the elusive vaccine. Here we discuss the current status of preclinical vaccine development, providing insights into alternative approaches to vaccine delivery and promising candidate vaccines. The state of the art of clinical development also is reviewed.

  7. Vaccination of rainbow trout against infectious hematopoietic necrosis (IHN) by using attenuated mutants selected by neutralizing monoclonal antibodies

    USGS Publications Warehouse

    Roberti, K.A.; Rohovec, J.S.; Winton, J.R.

    1998-01-01

    A neutralizing monoclonal antibody against infectious hematopoietic necrosis virus (IHNV) was used to select neutralization-resistant mutants from isolates of virus obtained from adult steelhead Oncorhynchus mykiss returning to the Round Butte Hatchery (RB mutants) on the Deschutes River in Oregon, USA, and from rainbow trout (nonanadromous O. mykiss) at a commercial hatchery in the Hagerman Valley of Idaho, USA (193-110 mutants). Two of the mutants, RB-1 and 193-110-4, were significantly (P 0.05) in protection among fish exposed to the RB-1 vaccine strain at a dose of 1 x 105 TCID50/mL for periods of either 1, 12, or 24 h, held for 14 d, and then challenged with the wild-type RB isolate, although the 1-h exposure seemed to be somewhat less effective. Fish were vaccinated with the RB-1 strain at 1 x 103-1 x 105 TCID50/mL for 24 h then challenged after 1, 7, 14, or 21 d with the wild-type RB isolate. No significant (P > 0.1) protection was observed at 1 d postvaccination, but the relative percent survival increased progressively at each subsequent challenge period, becoming statistically significant by day 7 (P < 0.001) and beyond. These results suggested that resistance to challenge with wild-type virus resulted from development of IHNV-specific immunity and not from viral interference or interferon induction, and they reinforce the potential of an attenuated vaccine to control this important disease.

  8. Oral Vaccination with Attenuated Salmonella typhimurium-Delivered TsPmy DNA Vaccine Elicits Protective Immunity against Trichinella spiralis in BALB/c Mice

    PubMed Central

    Wang, Lei; Wang, Xiaohuan; Bi, Kuo; Sun, Ximeng; Yang, Jing; Gu, Yuan; Huang, Jingjing; Zhan, Bin; Zhu, Xinping

    2016-01-01

    Background Our previous studies showed that Trichinella spiralis paramyosin (TsPmy) is an immunomodulatory protein that inhibits complement C1q and C8/C9 to evade host complement attack. Vaccination with recombinant TsPmy protein induced protective immunity against T. spiralis larval challenge. Due to the difficulty in producing TsPmy as a soluble recombinant protein, we prepared a DNA vaccine as an alternative approach in order to elicit a robust immunity against Trichinella infection. Methods and Findings The full-length TsPmy coding DNA was cloned into the eukaryotic expression plasmid pVAX1, and the recombinant pVAX1/TsPmy was transformed into attenuated Salmonella typhimurium strain SL7207. Oral vaccination of mice with this attenuated Salmonella-delivered TsPmy DNA vaccine elicited a significant mucosal sIgA response in the intestine and a systemic IgG antibody response with IgG2a as the predominant subclass. Cytokine analysis also showed a significant increase in the Th1 (IFN-γ, IL-2) and Th2 (IL-4, 5, 6, 10) responses in lymphocytes from the spleen and MLNs of immunized mice upon stimulation with TsPmy protein. The expression of the homing receptors CCR9/CCR10 on antibody secreting B cells may be related to the translocation of IgA-secreted B cells to local intestinal mucosa. The mice immunized with Salmonella-delivered TsPmy DNA vaccine produced a significant 44.8% reduction in adult worm and a 46.6% reduction in muscle larvae after challenge with T. spiralis larvae. Conclusion Our results demonstrated that oral vaccination with TsPmy DNA delivered by live attenuated S. typhimurium elicited a significant local IgA response and a mixed Th1/Th2 immune response that elicited a significant protection against T. spiralis infection in mice. PMID:27589591

  9. A Group B Coxsackievirus/Poliovirus 5′ Nontranslated Region Chimera Can Act as an Attenuated Vaccine Strain in Mice

    PubMed Central

    Chapman, Nora M.; Ragland, Anna; Leser, J. Smith; Höfling, Katja; Willian, Sandra; Semler, Bert L.; Tracy, Steven

    2000-01-01

    The linear, single-stranded enterovirus RNA genome is flanked at either end with a nontranslated region (NTR). By replacing the entire 5′ NTR of coxsackievirus B3 (CVB3) with that from type 1 poliovirus, a progeny virus was obtained following transfection of HeLa cells. The chimeric virus, CPV/49, replicates like the parental CVB3 strain in HeLa cells but is attenuated for replication and yield in primary human coronary artery endothelial cell cultures, in a human pancreas tumor cell line, and in primary murine heart fibroblast cultures. Western blotting analyses of CPV/49 replication in murine heart fibroblast cultures demonstrate that synthesis of CPV/49 proteins is significantly slower than that of the parental CVB3 strain. CPV/49 replicates in murine hearts and pancreata, causing no disease in hearts and a minor pancreatic inflammation in some mice that resolves by 28 days postinoculation. A single inoculation with CPV/49 induces protective anti-CVB3 neutralizing antibody titers that completely protect mice from both heart and pancreatic disease when mice are challenged 28 days p.i. with genetically diverse virulent strains of CVB3. That a chimeric CVB3 strain, created from sequences of two virulent viruses, is sufficiently attenuated to act as an avirulent, protective vaccine strain in mice suggests that chimeric genome technology merits further evaluation for the development of new nonpoliovirus enteroviral vectors. PMID:10756016

  10. Efficacy for a new live attenuated Salmonella Enteritidis vaccine candidate to reduce internal egg contamination.

    PubMed

    Nandre, R; Matsuda, K; Lee, J H

    2014-02-01

    To evaluate the efficacy of a novel attenuated Salmonella Enteritidis (△lon△cpxR) vaccine candidate (JOL919), chickens were immunized through oral and intramuscular routes to reduce egg contamination against S. Enteritidis challenge. Birds were orally immunized with JOL919 on the first day of life and were subsequently boosted in the 6th and 16th weeks through oral (group B) or intramuscular (group C) route, while control birds were unimmunized (group A). The chickens of all groups were challenged intravenously with the virulent S. Enteritidis strain in the 24th week. The immunized groups B and C showed significantly higher plasma IgG and intestinal secretory IgA levels as compared to those of the control group. The lymphocyte proliferation response and CD45(+) CD3(+) T-cell number in the peripheral blood of the groups B and C were significantly increased. In addition, the egg contamination rates were significantly lower in the group B (0%, 10.7% and 0%) and the group C (3.6%, 14.3% and 3.6%) as compared to the group A (28.6%, 42.8% and 28.6%) in the 1st, 2nd and 3rd weeks post-challenge. All animals in the groups B and C showed lower organ lesion scores in the liver and spleen and lower bacterial counts in the liver, spleen and ovary at the 3rd week post-challenge. These results indicate that this vaccine candidate can be an efficient tool for prevention of Salmonella infections by inducing protective humoral and cellular immune responses. In addition, this vaccine did not prevent egg contamination, but did appear to reduce incidence. Booster immunizations, especially via oral administration route, showed an efficient protection against internal egg contamination with S. Enteritidis.

  11. Novel approaches to develop Rift Valley fever vaccines.

    PubMed

    Indran, Sabarish V; Ikegami, Tetsuro

    2012-01-01

    Rift Valley fever (RVF) is endemic to sub-Saharan Africa, and has spread into Madagascar, Egypt, Saudi Arabia, and Yemen. Rift Valley fever virus (RVFV) of the family Bunyaviridae, genus Phlebovirus causes hemorrhagic fever, neurological disorders or blindness in humans, and high rate abortion and fetal malformation in ruminants. RVFV is classified as a Category A Priority pathogen and overlap select agent by CDC/USDA due to its potential impact on public health and agriculture. There is a gap in the safety and immunogenicity in traditional RVF vaccines; the formalin-inactivated RVFV vaccine TSI-GSD-200 requires three doses for protection, and the live-attenuated Smithburn vaccine has a risk to cause abortion and fetal malformation in pregnant ruminants. In this review, problems of traditional vaccines and the safety and efficacy of recently reported novel RVF candidate vaccines including subunit vaccines, virus vector, and replicons are discussed.

  12. Novel approaches to develop Rift Valley fever vaccines

    PubMed Central

    Indran, Sabarish V.; Ikegami, Tetsuro

    2012-01-01

    Rift Valley fever (RVF) is endemic to sub-Saharan Africa, and has spread into Madagascar, Egypt, Saudi Arabia, and Yemen. Rift Valley fever virus (RVFV) of the family Bunyaviridae, genus Phlebovirus causes hemorrhagic fever, neurological disorders or blindness in humans, and high rate abortion and fetal malformation in ruminants. RVFV is classified as a Category A Priority pathogen and overlap select agent by CDC/USDA due to its potential impact on public health and agriculture. There is a gap in the safety and immunogenicity in traditional RVF vaccines; the formalin-inactivated RVFV vaccine TSI-GSD-200 requires three doses for protection, and the live-attenuated Smithburn vaccine has a risk to cause abortion and fetal malformation in pregnant ruminants. In this review, problems of traditional vaccines and the safety and efficacy of recently reported novel RVF candidate vaccines including subunit vaccines, virus vector, and replicons are discussed. PMID:23112960

  13. The Long-Term Safety, Public Health Impact, and Cost-Effectiveness of Routine Vaccination with a Recombinant, Live-Attenuated Dengue Vaccine (Dengvaxia): A Model Comparison Study

    PubMed Central

    Longini, Ira; Lourenco, Jose; Pearson, Carl A. B.; Reiner, Robert C.; Mier-y-Terán-Romero, Luis; Vannice, Kirsten

    2016-01-01

    Background Large Phase III trials across Asia and Latin America have recently demonstrated the efficacy of a recombinant, live-attenuated dengue vaccine (Dengvaxia) over the first 25 mo following vaccination. Subsequent data collected in the longer-term follow-up phase, however, have raised concerns about a potential increase in hospitalization risk of subsequent dengue infections, in particular among young, dengue-naïve vaccinees. We here report predictions from eight independent modelling groups on the long-term safety, public health impact, and cost-effectiveness of routine vaccination with Dengvaxia in a range of transmission settings, as characterised by seroprevalence levels among 9-y-olds (SP9). These predictions were conducted for the World Health Organization to inform their recommendations on optimal use of this vaccine. Methods and Findings The models adopted, with small variations, a parsimonious vaccine mode of action that was able to reproduce quantitative features of the observed trial data. The adopted mode of action assumed that vaccination, similarly to natural infection, induces transient, heterologous protection and, further, establishes a long-lasting immunogenic memory, which determines disease severity of subsequent infections. The default vaccination policy considered was routine vaccination of 9-y-old children in a three-dose schedule at 80% coverage. The outcomes examined were the impact of vaccination on infections, symptomatic dengue, hospitalised dengue, deaths, and cost-effectiveness over a 30-y postvaccination period. Case definitions were chosen in accordance with the Phase III trials. All models predicted that in settings with moderate to high dengue endemicity (SP9 ≥ 50%), the default vaccination policy would reduce the burden of dengue disease for the population by 6%–25% (all simulations: –3%–34%) and in high-transmission settings (SP9 ≥ 70%) by 13%–25% (all simulations: 10%– 34%). These endemicity levels are

  14. Phase-I study MEDI-534, of a live, attenuated intranasal vaccine against respiratory syncytial virus and parainfluenza-3 virus in seropositive children.

    PubMed

    Gomez, Margarita; Mufson, Maurice A; Dubovsky, Filip; Knightly, Conor; Zeng, Wen; Losonsky, Genevieve

    2009-07-01

    A live, attenuated respiratory syncytial virus and parainfluenza virus type 3 vaccine was evaluated in healthy respiratory syncytial virus/parainfluenza virus type 3 seropositive children aged 1 to 9 years. Three cohorts of 40 children were randomized 1:1 to receive 10, 10, or 10 median tissue culture infectious dose50 MEDI-534 vaccine or placebo. The vaccine's safety profile was similar to placebo, no viral shedding was detected, and the vaccine was minimally immunogenic.

  15. Regulatory pathways for vaccines for developing countries.

    PubMed Central

    Milstien, Julie; Belgharbi, Lahouari

    2004-01-01

    Vaccines that are designed for use only in developing countries face regulatory hurdles that may restrict their use. There are two primary reasons for this: most regulatory authorities are set up to address regulation of products for use only within their jurisdictions and regulatory authorities in developing countries traditionally have been considered weak. Some options for regulatory pathways for such products have been identified: licensing in the country of manufacture, file review by the European Medicines Evaluation Agency on behalf of WHO, export to a country with a competent national regulatory authority (NRA) that could handle all regulatory functions for the developing country market, shared manufacturing and licensing in a developing country with competent manufacturing and regulatory capacity, and use of a contracted independent entity for global regulatory approval. These options have been evaluated on the basis of five criteria: assurance of all regulatory functions for the life of the product, appropriateness of epidemiological assessment, applicability to products no longer used in the domestic market of the manufacturing country, reduction of regulatory risk for the manufacturer, and existing rules and regulations for implementation. No one option satisfies all criteria. For all options, national infrastructures (including the underlying regulatory legislative framework, particularly to formulate and implement local evidence-based vaccine policy) must be developed. WHO has led work to develop this capacity with some success. The paper outlines additional areas of action required by the international community to assure development and use of vaccines needed for the developing world. PMID:15042235

  16. Safety and immunogenicity of a live-attenuated auxotrophic candidate vaccine against the intracellular pathogen Rhodococcus equi.

    PubMed

    Lopez, A M; Townsend, H G G; Allen, A L; Hondalus, M K

    2008-02-13

    Rhodococcus equi causes serious pneumonia in neonatal foals and is an opportunistic pathogen of people with compromised cellular immunity. No effective vaccine against R. equi disease in foals is available. We tested the safety and immunogenicity of a live, fully attenuated riboflavin auxotrophic candidate vaccine strain of R. equi (R. equi rib-). We demonstrated that R. equi rib- is immunogenic and capable of inducing IFN-gamma responses in immunocompetent BALB/c mice, yet it is safe even in an immunocompromised SCID mouse infection model. Moreover, it protects immunocompetent mice against virulent R. equi challenge. In foals, R. equi rib- was likewise safe and stimulated serum R. equi-specific immune responses. A preliminary immunization strategy did not afford protection against virulent R. equi challenge and therefore, optimization of the vaccine formulation and or vaccination protocol will be necessary.

  17. Developments in cancer vaccines for hepatocellular carcinoma.

    PubMed

    Buonaguro, Luigi

    2016-01-01

    Hepatocellular carcinoma (HCC) accounts for about 6 % of all new cancers diagnosed worldwide and represents one of the leading causes of cancer-related death globally in men and women, respectively. The overall prognosis for HCC patients is poor, especially in the majority of patients with more advanced stage of disease. Indeed, in such cases immunotherapeutic strategies may represent a novel and effective tool. A few immunotherapy trials conducted for HCC have provided divergent results, urging the scientific community to explore additional paths to improve efficacy of immunotherapeutic approaches. The "Cancer Vaccine development for Hepatocellular Carcinoma"-HEPAVAC Consortium has been funded by the EU within the FP7 with the goal of developing a novel therapeutic peptide-based cancer vaccine strategy for HCC including both "off-the-shelf" and personalized antigens. This will be one of the very few vaccine trials for HCC and the first multi-epitope, multi-target and multi-HLA allele therapeutic cancer vaccine for such a frequent and aggressive disease with a hitherto high unmet medical need. Feasibility, safety and biological efficacy will be evaluated in a randomized, controlled European multicenter phase I/II clinical trial.

  18. Attenuated Bordetella pertussis Vaccine Protects against Respiratory Syncytial Virus Disease via an IL-17–Dependent Mechanism

    PubMed Central

    Schnoeller, Corinna; Roux, Xavier; Sawant, Devika; Raze, Dominique; Olszewska, Wieslawa; Locht, Camille

    2014-01-01

    Rationale: We attenuated virulent Bordetella pertussis by genetically eliminating or detoxifying three major toxins. This strain, named BPZE1, is being developed as a possible live nasal vaccine for the prevention of whooping cough. It is immunogenic and safe when given intranasally in adult volunteers. Objectives: Before testing in human infants, we wished to examine the potential effect of BPZE1 on a common pediatric infection (respiratory syncytial virus [RSV]) in a preclinical model. Methods: BPZE1 was administered before or after RSV administration in adult or neonatal mice. Pathogen replication, inflammation, immune cell recruitment, and cytokine responses were measured. Measurements and Main Results: BPZE1 alone did not cause overt disease, but induced efflux of neutrophils into the airway lumen and production of IL-10 and IL-17 by mucosal CD4+ T cells. Given intranasally before RSV infection, BPZE1 markedly attenuated RSV, preventing weight loss, reducing viral load, and attenuating lung cell recruitment. Given neonatally, BPZE1 also protected against RSV-induced weight loss even through to adulthood. Furthermore, it markedly increased IL-17 production by CD4+ T cells and natural killer cells and recruited regulatory cells and neutrophils after virus challenge. Administration of anti–IL-17 antibodies ablated the protective effect of BPZE1 on RSV disease. Conclusions: Rather than enhancing RSV disease, BPZE1 protected against viral infection, modified viral responses, and enhanced natural mucosal resistance. Prevention of RSV infection by BPZE1 seems in part to be caused by induction of IL-17. Clinical trial registered with www.clinicaltrials.gov (NCT 01188512). PMID:24261996

  19. Longitudinal study to assess the safety and efficacy of a live-attenuated SHIV vaccine in long term immunized rhesus macaques

    SciTech Connect

    Yankee, Thomas M. Sheffer, Darlene; Liu Zhengian; Dhillon, Sukhbir; Jia Fenglan; Chebloune, Yahia; Stephens, Edward B.; Narayan, Opendra

    2009-01-05

    Live-attenuated viruses derived from SIV and SHIV have provided the most consistent protection against challenge with pathogenic viruses, but concerns regarding their long-term safety and efficacy have hampered their clinical usefulness. We report a longitudinal study in which we evaluated the long-term safety and efficacy of {delta}vpuSHIV{sub PPC}, a live virus vaccine derived from SHIV{sub PPC}. Macaques were administered two inoculations of {delta}vpuSHIV{sub PPC}, three years apart, and followed for eight years. None of the five vaccinated macaques developed an AIDS-like disease from the vaccine. At eight years, macaques were challenged with pathogenic SIV and SHIV. None of the four macaques with detectable cellular-mediated immunity prior to challenge had detectable viral RNA in the plasma. This study demonstrates that multiple inoculations of a live vaccine virus can be used safely and can significantly extend the efficacy of the vaccine, as compared to a single inoculation, which is efficacious for approximately three years.

  20. 78 FR 43219 - Prospective Grant of Exclusive License: Live Attenuated Dengue Tetravalent Vaccine Containing a...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-19

    ... et al., ``Development of Mutations Useful for Attenuating Dengue Viruses and Chimeric Dengue Viruses... Antigenic Chimeric Dengue Viruses 1,2,3, And 4'', United States Patent Application Number 10/970,640 (now...., ``Mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus...

  1. Development of an improved vaccine evaluation protocol to compare the efficacy of Newcastle disease vaccines.

    PubMed

    Cardenas-Garcia, Stivalis; Diel, Diego G; Susta, Leonardo; Lucio-Decanini, Eduardo; Yu, Qingzhong; Brown, Corrie C; Miller, Patti J; Afonso, Claudio L

    2015-03-01

    While there is typically 100% survivability in birds challenged with vNDV under experimental conditions, either with vaccines formulated with a strain homologous or heterologous (different genotype) to the challenge virus, vaccine deficiencies are often noted in the field. We have developed an improved and more stringent protocol to experimentally evaluate live NDV vaccines, and showed for the first time under experimental conditions that a statistically significant reduction in mortality can be detected with genotype matched vaccines. Using both vaccine evaluation protocols (traditional and improved), birds were challenged with a vNDV of genotype XIII and the efficacy of live heterologous (genotype II) and homologous (genotype XIII) NDV vaccines was compared. Under traditional vaccination conditions there were no differences in survival upon challenge, but the homologous vaccine induced significantly higher levels of antibodies specific to the challenge virus. With the more stringent challenge system (multiple vaccine doses and early challenge with high titers of vNDV), the birds administered the homologous vaccine had superior humoral responses, reduced clinical signs, and reduced mortality levels than those vaccinated with the heterologous vaccine. These results provide basis for the implementation of more sensitive methods to evaluate vaccine efficacy.

  2. Temperature-sensitive mutations for live-attenuated Rift Valley fever vaccines: implications from other RNA viruses

    PubMed Central

    Nishiyama, Shoko; Ikegami, Tetsuro

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to the African continent. RVF is characterized by high rate of abortions in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. RVF is caused by the Rift Valley fever virus (RVFV: genus Phlebovirus, family Bunyaviridae). Vaccination is the only known effective strategy to prevent the disease, but there are no licensed RVF vaccines available for humans. A live-attenuated vaccine candidate derived from the wild-type pathogenic Egyptian ZH548 strain, MP-12, has been conditionally licensed for veterinary use in the U.S. MP-12 displays a temperature-sensitive (ts) phenotype and does not replicate at 41°C. The ts mutation limits viral replication at a specific body temperature and may lead to an attenuation of the virus. Here we will review well-characterized ts mutations for RNA viruses, and further discuss the potential in designing novel live-attenuated vaccines for RVF. PMID:26322023

  3. Temperature-sensitive mutations for live-attenuated Rift Valley fever vaccines: implications from other RNA viruses.

    PubMed

    Nishiyama, Shoko; Ikegami, Tetsuro

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to the African continent. RVF is characterized by high rate of abortions in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. RVF is caused by the Rift Valley fever virus (RVFV: genus Phlebovirus, family Bunyaviridae). Vaccination is the only known effective strategy to prevent the disease, but there are no licensed RVF vaccines available for humans. A live-attenuated vaccine candidate derived from the wild-type pathogenic Egyptian ZH548 strain, MP-12, has been conditionally licensed for veterinary use in the U.S. MP-12 displays a temperature-sensitive (ts) phenotype and does not replicate at 41°C. The ts mutation limits viral replication at a specific body temperature and may lead to an attenuation of the virus. Here we will review well-characterized ts mutations for RNA viruses, and further discuss the potential in designing novel live-attenuated vaccines for RVF.

  4. Protective efficacy of a live attenuated Mycoplasma hyopneumoniae vaccine with an ISCOM-matrix adjuvant in pigs.

    PubMed

    Xiong, Qiyan; Wei, Yanna; Feng, Zhixin; Gan, Yuan; Liu, Zhanjun; Liu, Maojun; Bai, Fangfang; Shao, Guoqing

    2014-02-01

    An attenuated Mycoplasma hyopneumoniae vaccine that requires intrathoracic administration is commercially available for use against mycoplasmal pneumonia in China. Given the limitations of such a route of administration, this study was undertaken to assess the capacity of an ISCOM-matrix adjuvant to enhance immunogenicity following intramuscular use. Immune responses in pigs following vaccination and subsequent intra-tracheal bacterial inoculation were examined using lymphocyte proliferation, serology and mucosal IgA in both nasal and saliva swabs. Vaccination induced clear lymphocyte proliferation, but only slight serum antibody responses although these were significantly increased following experimental infection. Mucosal IgA was not detected in either nasal or salivary secretions. Following bacterial challenge, animals vaccinated with the adjuvant-containing live vaccine exhibited less severe pulmonary lesions (median score 3.67) than unvaccinated pigs (median score 13.58). The degree of ciliary loss on the respiratory tract surface was reduced in vaccinated pigs compared with experimentally infected controls. The findings indicated that the adjuvant vaccine administered IM provided protection against experimentally induced mycoplasmal pneumonia and could have commercial potential.

  5. [A molecular basis of the plague vaccine development].

    PubMed

    Dentovskaia, S V; Kopylov, P Kh; Ivanov, S A; Ageev, S A; Anisimov, A P

    2013-01-01

    Molecular mechanisms of the Yersinia pestis pathogenicity and peculiarities of maturation of specific immunity to plague are reviewed. The history and modern state of the plague vaccine development are described. Special attention is focused on the prospects in the area of the plague vaccine development. The possible approaches to improvement of vaccine preparations are discussed.

  6. Model for product development of vaccines against neglected tropical diseases: a vaccine against human hookworm.

    PubMed

    Bottazzi, Maria Elena; Brown, Ami Shah

    2008-12-01

    This article provides an overview of the advances in product development and technology transfer of the vaccine against human hookworm, with particular emphasis on the lessons learned and the challenges of developing a vaccine in the nonprofit sector. The comprehensive approach to vaccine development established by the Human Hookworm Vaccine Initiative (HHVI) identifies key operational and technical aspects that are essential for a successful partnership with a developing country vaccine manufacturer. This article also highlights the importance of a global access roadmap to guide the vaccine development program. The advancement of new products for the control of neglected tropical diseases portends great challenges for global access, including aspects related to vaccine design, product development and manufacture, vaccine introduction and distribution, financing, knowledge dissemination and intellectual property management. With only three vaccines for neglected tropical diseases in clinical trials - hookworm, leishmaniasis and schistosomiasis - we are at the nascent stages of developing vaccines for neglected populations. Product development public-private partnerships, such as the HHVI, continue to show great promise on this front and will eventually provide significant control tools for achieving millennium development goals related to poverty reduction, as well as child and maternal health.

  7. Policy making for vaccine use as a driver of vaccine innovation and development in the developed world.

    PubMed

    Seib, Katherine; Pollard, Andrew J; de Wals, Philippe; Andrews, Ross M; Zhou, Fangjun; Hatchett, Richard J; Pickering, Larry K; Orenstein, Walter A

    2017-03-07

    In the past 200years, vaccines have had unmistakable impacts on public health including declines in morbidity and mortality, most markedly in economically-developed countries. Highly engineered vaccines including vaccines for conditions other than infectious diseases are expected to dominate future vaccine development. We examine immunization vaccine policy as a driver of vaccine innovation and development. The pathways to recommendation for use of licensed vaccines in the US, UK, Canada and Australia have been similar, including: expert review of disease epidemiology, disease burden and severity; vaccine immunogenicity, efficacy and safety; programmatic feasibility; public demand; and increasingly cost-effectiveness. Other attributes particularly important in development of future vaccines are likely to include: duration of immunity for improved vaccines such as pertussis; a greater emphasis on optimizing community protection rather than direct protection only; programmatic implementation, feasibility, improvements (as in the case of development of a universal influenza vaccine); public concerns/confidence/fears related to outbreak pathogens like Ebola and Zika virus; and major societal burden for combating hard to treat diseases like HIV and antimicrobial resistant pathogens. Driving innovation and production of future vaccines faces enormous economic hurdles as available approaches, technologies and regulatory pathways become more complex. As such, cost-mitigating strategies and focused, aligned efforts (by governments, private organizations, and private-public partnerships) will likely be needed to continue to spur major advances in vaccine technologies and development.

  8. Immune effects of the vaccine of live attenuated Aeromonas hydrophila screened by rifampicin on common carp (Cyprinus carpio L).

    PubMed

    Jiang, Xinyu; Zhang, Chao; Zhao, Yanjing; Kong, Xianghui; Pei, Chao; Li, Li; Nie, Guoxing; Li, Xuejun

    2016-06-08

    Aeromonas hydrophila, as a strong Gram-negative bacterium, can infect a wide range of freshwater fish, including common carp Cyprinus carpio, and cause the huge economic loss. To create the effective vaccine is the best way to control the outbreak of the disease caused by A. hydrophila. In this study, a live attenuated A. hydrophila strain, XX1LA, was screened from the pathogenic A. hydrophila strain XX1 cultured on medium containing the antibiotic rifampicin, which was used as a live attenuated vaccine candidate. The immune protection of XX1LA against the pathogen A. hydrophila in common carp was evaluated by the relative percent survival (RPS), the specific IgM antibody titers, serum lysozyme activity and the expression profiles of multiple immune-related genes at the different time points following immunization. The results showed that the variable up-regulations of the immune-related genes, such as the pro-inflammatory cytokine IL-1β, the chemokine IL-10 and IgM, were observed in spleen and liver of common carp injected in the vaccines with the formalin-killed A. hydrophila (FKA) and the live attenuated XX1LA. Specific antibody to A. hydrophila was found to gradually increase during 28 days post-vaccination (dpv), and the RPS (83.7%) in fish vaccinated with XX1LA, was significant higher than that (37.2%) in fish vaccinated with FKA (P<0.05) on Day 28 after challenged by pathogen. It was demonstrated that the remarkable immune protection presented in the group vaccinated with XX1LA. During the late stage of 4-week immunization phase, compared with FKA and the control, specific IgM antibody titers significantly increased (P<0.05) in the XX1LA group. The activity of the lysozyme in serum indicated no significant change among three groups. In summary, the live attenuated bacterial vaccine XX1LA, screened in this study, indicates the better protect effect on common carp against A. hydrophila, which can be applied in aquaculture of common carp to prevent from the

  9. Development of Leishmania vaccines: predicting the future from past and present experience

    PubMed Central

    Mutiso, Joshua Muli; Macharia, John Chege; Kiio, Maria Ndunge; Ichagichu, James Maina; Rikoi, Hitler; Gicheru, Michael Muita

    2013-01-01

    Leishmaniasis is a disease that ranges in severity from skin lesions to serious disfigurement and fatal systemic infection. Resistance to infection is associated with a T-helper-1 immune response that activates macrophages to kill the intracellular parasite in a nitric oxide-dependent manner. Conversely, disease progression is generally associated with a T-helper-2 response that activates humoral immunity. Current control is based on chemotherapeutic treatments which are expensive, toxic and associated with high relapse and resistance rates. Vaccination remains the best hope for control of all forms of the disease, and the development of a safe, effective and affordable antileishmanial vaccine is a critical global public-health priority. Extensive evidence from studies in animal models indicates that solid protection can be achieved by immunization with defined subunit vaccines or live-attenuated strains of Leishmania. However, to date, no vaccine is available despite substantial efforts by many laboratories. Major impediments in Leishmania vaccine development include: lack of adequate funding from national and international agencies, problems related to the translation of data from animal models to human disease, and the transition from the laboratory to the field. Furthermore, a thorough understanding of protective immune responses and generation and maintenance of the immunological memory, an important but least-studied aspect of antiparasitic vaccine development, during Leishmania infection is needed. This review focuses on the progress of the search for an effective vaccine against human and canine leishmaniasis. PMID:23554800

  10. Advances in the development of enterohemorrhagic Escherichia coli vaccines using murine models of infection.

    PubMed

    Garcia-Angulo, Victor A; Kalita, Anjana; Torres, Alfredo G

    2013-07-11

    Enterohemorrhagic Escherichia coli (EHEC) strains are food borne pathogens with importance in public health. EHEC colonizes the large intestine and causes diarrhea, hemorrhagic colitis and in some cases, life-threatening hemolytic-uremic syndrome (HUS) due to the production of Shiga toxins (Stx). The lack of effective clinical treatment, sequelae after infection and mortality rate in humans supports the urgent need of prophylactic approaches, such as development of vaccines. Shedding from cattle, the main EHEC reservoir and considered the principal food contamination source, has prompted the development of licensed vaccines that reduce EHEC colonization in ruminants. Although murine models do not fully recapitulate human infection, they are commonly used to evaluate EHEC vaccines and the immune/protective responses elicited in the host. Mice susceptibility differs depending of the EHEC inoculums; displaying different mortality rates and Stx-mediated renal damage. Therefore, several experimental protocols have being pursued in this model to develop EHEC-specific vaccines. Recent candidate vaccines evaluated include those composed of virulence factors alone or as fused-subunits, DNA-based, attenuated bacteria and bacterial ghosts. In this review, we summarize progress in the design and testing of EHEC vaccines and the use of different strategies for the evaluation of novel EHEC vaccines in the murine model.

  11. Immune correlates for dengue vaccine development.

    PubMed

    Srikiatkhachorn, Anon; Yoon, In-Kyu

    2016-01-01

    Dengue virus is the leading cause of vector-borne viral disease with four serotypes in circulation. Vaccine development has been complicated by the potential for both protection and disease enhancement during heterologous infection. Secondary infection triggers cross-reactive immune memory responses that have varying functional and epitope specificities that determine protection or risk. Strongly neutralizing antibodies to quaternary epitopes may be especially important for virus neutralization. Cell-mediated immunity dominated by Th1 functions may also play an important role. Determining an immune correlate of protection or risk would be highly beneficial for vaccine development but is hampered by mechanistic uncertainties and assay limitations. Clinical efficacy trials and human infection models along with a systems approach may provide future opportunities to elucidate such correlates.

  12. Watching Every Step of the Way: Junín Virus Attenuation Markers in the Vaccine Lineage

    PubMed Central

    Stephan, Betina Inés; Lozano, Mario Enrique; Goñi, Sandra Elizabeth

    2013-01-01

    The Arenaviridae family includes several hemorrhagic fever viruses which are important emerging pathogens. Junín virus, a member of this family, is the etiological agent of Argentine Hemorrhagic Fever (AHF). A collaboration between the Governments of Argentina and the USA rendered the attenuated Junín virus vaccine strain Candid#1. Arenaviruses are enveloped viruses with genomes consisting of two single-stranded RNA species (L and S), each carrying two coding regions separated by a stably structured, non-coding intergenic region. Molecular characterization of the vaccine strain and of its more virulent ancestors, XJ13 (prototype) and XJ#44, allows a systematic approach for the discovery of key elements in virulence attenuation. We show comparisons of sequence information for the S RNA of the strains XJ13, XJ#44 and Candid#1 of Junín virus, along with other strains from the vaccine lineage and a set of Junín virus field strains collected at the AHF endemic area. Comparisons of nucleotide and amino acid sequences revealed different point mutations which might be linked to the attenuated phenotype. The majority of changes are consistent with a progressive attenuation of virulence between XJ13, XJ#44 and Candid#1. We propose that changes found in genomic regions with low natural variation frequencies are more likely to be associated with the virulence attenuation process. We partially sequenced field strains to analyze the genomic variability naturally occurring for Junín virus. This information, together with the sequence analysis of strains with intermediate virulence, will serve as a starting point to study the molecular bases for viral attenuation. PMID:24396274

  13. Attenuation, persistence, and vaccine potential of an Edwardsiella ictaluri purA mutant.

    PubMed Central

    Lawrence, M L; Cooper, R K; Thune, R L

    1997-01-01

    In this study, an adenine-auxotrophic strain of Edwardsiella ictaluri was constructed and its virulence, tissue persistence, and vaccine efficacy were evaluated. A clone containing the purA gene was isolated from an E. ictaluri genomic library, sequenced, and shown to have an overall sequence identity of 79.3% at the nucleotide level and 85.7% at the amino acid level with the Escherichia coli purA gene. The cloned E. ictaluri purA gene was mutated by deleting a 598-bp segment of the gene and inserting the kanamycin resistance gene from Tn903 into the gap. The delta purA::Km(r) gene was subcloned into the suicide plasmid pGP704, and the resulting plasmid was used to deliver the modified gene into a virulent strain of E. ictaluri by conjugation. Homologous recombination replaced the chromosomal purA gene with the mutated gene to create an adenine-auxotrophic strain (LSU-E2). Compared to wild-type E. ictaluri, LSU-E2 was highly attenuated by the injection, immersion, and oral routes of exposure. By the injection route, LSU-E2 had a 50% lethal dose (LD50) that was greater than 5 logs10 higher than the LD50 for wild-type E. ictaluri. In a tissue persistence study, LSU-E2 was able to invade channel catfish by the immersion route and persist in internal organs for at least 48 h. Channel catfish that were vaccinated with a single immersion dose of LSU-E2 had mortality significantly lower (P < 0.01) following a wild-type E. ictaluri challenge than that of nonvaccinated fish. PMID:9353045

  14. Comparative genomic analysis of Brucella melitensis vaccine strain M5 provides insights into virulence attenuation.

    PubMed

    Jiang, Hai; Du, Pengcheng; Zhang, Wen; Wang, Heng; Zhao, Hongyan; Piao, Dongri; Tian, Guozhong; Chen, Chen; Cui, Buyun

    2013-01-01

    The Brucella melitensis vaccine strain M5 is widely used to prevent and control brucellosis in animals. In this study, we determined the whole-genome sequence of M5, and conducted a comprehensive comparative analysis against the whole-genome sequence of the virulent strain 16 M and other reference strains. This analysis revealed 11 regions of deletion (RDs) and 2 regions of insertion (RIs) within the M5 genome. Among these regions, the sequences encompassed in 5 RDs and 1 RI showed consistent variation, with a large deletion between the M5 and the 16 M genomes. RD4 and RD5 showed the large diversity among all Brucella genomes, both in RD length and RD copy number. Thus, RD4 and RD5 are potential sites for typing different Brucella strains. Other RD and RI regions exhibited multiple single nucleotide polymorphisms (SNPs). In addition, a genome fragment with a 56 kb rearrangement was determined to be consistent with previous studies. Comparative genomic analysis indicated that genomic island inversion in Brucella was widely present. With the genetic pattern common among all strains analyzed, these 2 RDs, 1 RI, and one inversion region are potential sites for detection of genomic differences. Several SNPs of important virulence-related genes (motB, dhbC, sfuB, dsbAB, aidA, aroC, and lysR) were also detected, and may be used to determine the mechanism of virulence attenuation. Collectively, this study reveals that comparative analysis between wild-type and vaccine strains can provide resources for the study of virulence and microevolution of Brucella.

  15. Comparative Genomic Analysis of Brucella melitensis Vaccine Strain M5 Provides Insights into Virulence Attenuation

    PubMed Central

    Zhang, Wen; Wang, Heng; Zhao, Hongyan; Piao, Dongri; Tian, Guozhong; Chen, Chen; Cui, Buyun

    2013-01-01

    The Brucella melitensis vaccine strain M5 is widely used to prevent and control brucellosis in animals. In this study, we determined the whole-genome sequence of M5, and conducted a comprehensive comparative analysis against the whole-genome sequence of the virulent strain 16 M and other reference strains. This analysis revealed 11 regions of deletion (RDs) and 2 regions of insertion (RIs) within the M5 genome. Among these regions, the sequences encompassed in 5 RDs and 1 RI showed consistent variation, with a large deletion between the M5 and the 16 M genomes. RD4 and RD5 showed the large diversity among all Brucella genomes, both in RD length and RD copy number. Thus, RD4 and RD5 are potential sites for typing different Brucella strains. Other RD and RI regions exhibited multiple single nucleotide polymorphisms (SNPs). In addition, a genome fragment with a 56 kb rearrangement was determined to be consistent with previous studies. Comparative genomic analysis indicated that genomic island inversion in Brucella was widely present. With the genetic pattern common among all strains analyzed, these 2 RDs, 1 RI, and one inversion region are potential sites for detection of genomic differences. Several SNPs of important virulence-related genes (motB, dhbC, sfuB, dsbAB, aidA, aroC, and lysR) were also detected, and may be used to determine the mechanism of virulence attenuation. Collectively, this study reveals that comparative analysis between wild-type and vaccine strains can provide resources for the study of virulence and microevolution of Brucella. PMID:23967122

  16. Efficacy of HVT-IBD vector vaccine compared to attenuated live vaccine using in-ovo vaccination against a Korean very virulent IBDV in commercial broiler chickens.

    PubMed

    Roh, J-H; Kang, M; Wei, B; Yoon, R-H; Seo, H-S; Bahng, J-Y; Kwon, J-T; Cha, S-Y; Jang, H-K

    2016-05-01

    The production performance, efficacy, and safety of two types of vaccines for infectious bursal disease virus (IBDV) were compared with in-ovo vaccination of Cobb 500 broiler chickens for gross and microscopic examination of the bursa of Fabricius, bursa/body weight (b/B) ratio, flow cytometry, and serologic response to Newcastle disease virus (NDV) vaccination. One vaccine was a recombinant HVT-IBD vector vaccine (HVT as for herpesvirus of turkeys) and the other was an intermediate plus live IBDV vaccine. A significant difference was detected at 21 d. Eight of 10 chickens that received the IBDV live vaccine had severe bursal lesions and a relatively low b/B ratio of 0.95, and an inhibited NDV vaccine response. On the other hand, the HVT-IBD vector vaccine resulted in mild bursal lesions and a b/B ratio of 1.89. Therefore, the live vaccine had lower safety than that of the HVT-IBD vector vaccine. To determine the protective efficacy, chickens were intraocularly challenged at 24 d. Eight of 10 chickens in the IBDV live vaccination group showed gross and histological lesions characterized by hemorrhage, cyst formation, lymphocytic depletion, and a decreased b/B ratio. In contrast, the HVT-IBD vector vaccinated chickens showed mild gross and histological lesions in three of 10 chickens with a b/B ratio of 1.36, which was similar to that of the unchallenged controls. Vaccinated chickens showed a significant increase in IBDV antibody titers, regardless of the type of vaccine used. In addition, significantly better broiler flock performance was observed with the HVT-IBD vector vaccine compared to that of the live vaccine. Our results revealed that the HVT-IBD vector vaccine could be used as an alternative vaccine to increase efficacy, and to have an improved safety profile compared with the IBDV live vaccine using in-ovo vaccination against the Korean very virulent IBDV in commercial broiler chickens.

  17. Efficiency of live attenuated and inactivated rabies viruses in prophylactic and post exposure vaccination against the street virus strain.

    PubMed

    Huang, F; Ahmad, W; Duan, M; Liu, Z; Guan, Z; Zhang, M; Qiao, B; Li, Y; Song, Y; Song, Y; Chen, Y; Amjad Ali, M

    2015-06-01

    Rabies remains an enigmatic and widely discussed global infectious disease and causes an increasing number of deaths. The currently used highly effective prophylactic and post exposure (p.e.) vaccination depends solely upon inexpensive, effective and safe vaccines to counteract the spread of the disease. In this study, the potential of an attenuated Chinese rabies vaccine (SRV9) strain in prophylactic and p.e. vaccination against the street strain of rabies virus (RV) was evaluated in mice. Prophylactic vaccination consisting of one intramuscular (i.m.) dose of SRV9 protected 100% of mice from intracerebral (i.c.) challenge with a lethal dose of the street virus. The latter was detected in the brain of mice at day 6 post challenge by RT-PCR. Post exposure vaccination was performed at days 1, 2, 3, 4, 5 and 6 post infection (p.i.) with either SRV9 or inactivated rabies vaccine. The survival rates after i.m. inoculation of SRV9 at the indicated days were 70%, 50%, 30%, 20%, 10%, and 0%, respectively; the corresponding survival rates for the inactivated rabies vaccine were 30%, 20%, 10%, 0%, 0%, and 0%, respectively. However, 100%, 90%, 70%, 50%, 20%, 10%, and 10% of mice survived after i.c. inoculation of SRV9 at the indicated days. The increased permeability of the blood-brain barrier and the infiltration of CD19+ B cells into the central nervous system after i.c. inoculation of SRV9 are regarded as prerequisites for the clearance of the street virus. The obtained data suggest that SRV9 is a promising candidate for prophylactic and p.e. vaccination against rabies infection and that it exhibits a potential for the control of rabies in China.

  18. A live attenuated human metapneumovirus vaccine strain provides complete protection against homologous viral infection and cross-protection against heterologous viral infection in BALB/c mice.

    PubMed

    Liu, Ping; Shu, Zhou; Qin, Xian; Dou, Ying; Zhao, Yao; Zhao, Xiaodong

    2013-08-01

    A live attenuated vaccine candidate strain (M2) of human metapneumovirus (hMPV) was generated by removing the N-linked carbohydrate at amino acid 172 in the fusion (F) protein. Previously, replication of M2 in mouse lungs could be detected by molecular assays but not by viral titration. In the present study, the protective effects of M2 against infection by homologous or heterologous viruses were evaluated in BALB/c mice. Immunization with M2 produced a high titer of serum virus-neutralizing antibodies in BALB/c mice at 4 and 8 weeks postimmunization, with the titers against the homologous virus being higher than those against the heterologous virus. Challenges at 4 and 8 weeks postinoculation with M2 or wild-type virus led to no replication when mice were challenged with a homologous virus and extremely reduced replication when mice were challenged with a heterologous virus, as determined by the detection of viral genomic RNA copies in the lungs, as well as significantly milder pulmonary pathology. Thus, M2, with only one N-linked carbohydrate removed in the F protein, provides complete protection from homologous virus infection and substantial cross-protection from heterologous virus infection for at least 56 days after inoculation. This vaccine strain may therefore be a candidate for further preclinical study. Furthermore, this attenuating strategy (changing the glycosylation of a major viral protein) may be useful in the development of other viral vaccines.

  19. Evaluation of the Salmonella enterica Serovar Pullorum Pathogenicity Island 2 Mutant as a Candidate Live Attenuated Oral Vaccine

    PubMed Central

    Yin, Junlei; Cheng, Zhao; Wang, Xiaochun; Xu, Lijuan; Li, Qiuchun; Geng, Shizhong

    2015-01-01

    Salmonella enterica serovar Pullorum (S. Pullorum) is a highly adapted pathogen that causes pullorum disease (PD), an important systemic disease of poultry that causes severe economic losses in developing countries. In the interests of developing a safe and immunogenic oral vaccine, the efficacy of a Salmonella pathogenicity island 2 (SPI2)-deleted mutant of S. Pullorum (S06004ΔSPI2) was evaluated in chickens. S06004ΔSPI2 was severely less virulent than the parental wild-type strain S06004 as determined by the 50% lethal dose (LD50) for 3-day-old chickens when injected intramuscularly. Two-day-old chickens immunized with a single oral dose of S06004ΔSPI2 showed no differences in body weight or clinical symptoms compared with those in the negative-control group. S06004ΔSPI2 bacteria were not isolated from livers or spleens of immunized chickens after a short period of time, and specific humoral and cellular immune responses were significantly induced. Immunized chickens were challenged with S. Pullorum strain S06004 and Salmonella enterica serovar Gallinarum (S. Gallinarum) strain SG9 at 10 days postimmunization (dpi), and efficient protection against the challenges was observed. None of the immunized chickens died, the clinical symptoms were slight and temporary following challenge in immunized chickens compared with those in the control group, and these chickens recovered by 3 to 5 dpi. Overall, these results demonstrate that S06004ΔSPI2 can be used as a live attenuated oral vaccine. PMID:25924763

  20. Varicella zoster vaccines and their implications for development of HSV vaccines

    SciTech Connect

    Gershon, Anne A.

    2013-01-05

    Live attenuated vaccines to prevent varicella and zoster have been available in the US for the past 17 years, with a resultant dramatic decrease in varicella incidence and a predicted future decrease in the incidence of zoster. The pathogenesis and immune responses to varicella zoster virus (VZV) as well as the safety and effectiveness of VZV vaccines are reviewed. The lack of sterilizing immunity provided by VZV vaccines has not prevented them from being safe and effective. Virological and pathological information concerning parallels and differences between VZV and herpes simplex virus (HSV) are highlighted. Although VZV and HSV are distinct pathogens, they appear to have similarities in target organs and immunity that provide an expectation of a high likelihood for the success of vaccination against HSV, and predicted to be similar to that of VZV.

  1. Development of duck hepatitis A virus type 3 vaccine and its use to protect ducklings against infections.

    PubMed

    Kim, Min-Chul; Kim, Min-Jeong; Kwon, Yong-Kuk; Lindberg, A Michael; Joh, Seong-Joon; Kwon, Hyuk-Man; Lee, Youn-Jeong; Kwon, Jun-Hun

    2009-11-12

    A variant type of duck hepatitis A virus (DHAV), DHAV-3 was recently discovered in South Korea and China. Sequence analyses verified that the variant is genetically or serologically different from the DHAV-1 and DHAV-2 types. Duck hepatitis had been reported in South Korea since 1985 and an attenuated DHAV-1 vaccine had efficiently prevented epidemics of DHAV-1 until 2002. Despite the DHAV-1 based vaccine in use the novel DHAV-3 circulating in South Korea remains to be a threat to duckling farming. To develop a live attenuated vaccine against DHAV-3, a representative isolate, AP-04203, was therefore attenuated by repeated passages in SPF chicken embryos 100 times. The 100th passaged virus, AP-04203P100, did not cause clinical sign and mortality in 1-day-old ducklings as well as reversion of virulence capacity. The ducklings vaccinated with AP-04203P100 virus (10(3.0)ELD(50)/0.2ml) on 1-day-old age via the intramuscular injection were well protected from 2 days after challenge with pathogenic AP04203P1 virus via the intramuscular route. In addition, the vaccine candidate also exhibited complete protection against currently circulating pathogenic DHAV-3 isolates. In conclusion, we demonstrate that the live attenuated virus, AP-04203P100, is a promising vaccine candidate facilitating the prevention of duck hepatitis caused by DHAV-3 around East Asia including South Korea.

  2. Cold-Adapted Viral Attenuation (CAVA): Highly Temperature Sensitive Polioviruses as Novel Vaccine Strains for a Next Generation Inactivated Poliovirus Vaccine.

    PubMed

    Sanders, Barbara P; de Los Rios Oakes, Isabel; van Hoek, Vladimir; Bockstal, Viki; Kamphuis, Tobias; Uil, Taco G; Song, Yutong; Cooper, Gillian; Crawt, Laura E; Martín, Javier; Zahn, Roland; Lewis, John; Wimmer, Eckard; Custers, Jerome H H V; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2016-03-01

    The poliovirus vaccine field is moving towards novel vaccination strategies. Withdrawal of the Oral Poliovirus Vaccine and implementation of the conventional Inactivated Poliovirus Vaccine (cIPV) is imminent. Moreover, replacement of the virulent poliovirus strains currently used for cIPV with attenuated strains is preferred. We generated Cold-Adapted Viral Attenuation (CAVA) poliovirus strains by serial passage at low temperature and subsequent genetic engineering, which contain the capsid sequences of cIPV strains combined with a set of mutations identified during cold-adaptation. These viruses displayed a highly temperature sensitive phenotype with no signs of productive infection at 37°C as visualized by electron microscopy. Furthermore, decreases in infectious titers, viral RNA, and protein levels were measured during infection at 37°C, suggesting a block in the viral replication cycle at RNA replication, protein translation, or earlier. However, at 30°C, they could be propagated to high titers (9.4-9.9 Log10TCID50/ml) on the PER.C6 cell culture platform. We identified 14 mutations in the IRES and non-structural regions, which in combination induced the temperature sensitive phenotype, also when transferred to the genomes of other wild-type and attenuated polioviruses. The temperature sensitivity translated to complete absence of neurovirulence in CD155 transgenic mice. Attenuation was also confirmed after extended in vitro passage at small scale using conditions (MOI, cell density, temperature) anticipated for vaccine production. The inability of CAVA strains to replicate at 37°C makes reversion to a neurovirulent phenotype in vivo highly unlikely, therefore, these strains can be considered safe for the manufacture of IPV. The CAVA strains were immunogenic in the Wistar rat potency model for cIPV, inducing high neutralizing antibody titers in a dose-dependent manner in response to D-antigen doses used for cIPV. In combination with the highly productive

  3. Cold-Adapted Viral Attenuation (CAVA): Highly Temperature Sensitive Polioviruses as Novel Vaccine Strains for a Next Generation Inactivated Poliovirus Vaccine

    PubMed Central

    Sanders, Barbara P.; de los Rios Oakes, Isabel; van Hoek, Vladimir; Bockstal, Viki; Kamphuis, Tobias; Uil, Taco G.; Song, Yutong; Cooper, Gillian; Crawt, Laura E.; Martín, Javier; Zahn, Roland; Lewis, John; Wimmer, Eckard; Custers, Jerome H. H. V.; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2016-01-01

    The poliovirus vaccine field is moving towards novel vaccination strategies. Withdrawal of the Oral Poliovirus Vaccine and implementation of the conventional Inactivated Poliovirus Vaccine (cIPV) is imminent. Moreover, replacement of the virulent poliovirus strains currently used for cIPV with attenuated strains is preferred. We generated Cold-Adapted Viral Attenuation (CAVA) poliovirus strains by serial passage at low temperature and subsequent genetic engineering, which contain the capsid sequences of cIPV strains combined with a set of mutations identified during cold-adaptation. These viruses displayed a highly temperature sensitive phenotype with no signs of productive infection at 37°C as visualized by electron microscopy. Furthermore, decreases in infectious titers, viral RNA, and protein levels were measured during infection at 37°C, suggesting a block in the viral replication cycle at RNA replication, protein translation, or earlier. However, at 30°C, they could be propagated to high titers (9.4–9.9 Log10TCID50/ml) on the PER.C6 cell culture platform. We identified 14 mutations in the IRES and non-structural regions, which in combination induced the temperature sensitive phenotype, also when transferred to the genomes of other wild-type and attenuated polioviruses. The temperature sensitivity translated to complete absence of neurovirulence in CD155 transgenic mice. Attenuation was also confirmed after extended in vitro passage at small scale using conditions (MOI, cell density, temperature) anticipated for vaccine production. The inability of CAVA strains to replicate at 37°C makes reversion to a neurovirulent phenotype in vivo highly unlikely, therefore, these strains can be considered safe for the manufacture of IPV. The CAVA strains were immunogenic in the Wistar rat potency model for cIPV, inducing high neutralizing antibody titers in a dose-dependent manner in response to D-antigen doses used for cIPV. In combination with the highly productive

  4. Challenges in the development, licensure, and use of combination vaccines.

    PubMed

    Postema, A S; Myers, M G; Breiman, R F

    2001-12-15

    Before substantial public health benefits associated with use of combination vaccines can be realized, a variety of challenges must be addressed. In February 2000, the National Vaccine Program Office convened the International Symposium on Combination Vaccines to explore solutions for barriers to development, licensure, and use of safe and effective combination vaccines. The symposium focused on the following questions: (1) What immunologic standards should be used to evaluate new combination vaccines? (2) How should correlates of protection be developed, and how should the data they provide be interpreted? (3) What sample size is adequate for prelicensure safety trials of combination vaccines? (4) Should standards for evaluation of combination vaccines containing licensed components be different from standards for evaluation of combinations containing unlicensed components? (5) How can the "great expectations" of postlicensure surveillance be realized? Available data relevant to these issues were presented, providing a foundation for furthering the science of combination vaccines.

  5. Global Efforts in the Development of Vaccines for Tuberculosis: Requirements for Improved Vaccines Against Mycobacterium tuberculosis.

    PubMed

    Méndez-Samperio, P

    2016-10-01

    Currently, more than 9.0 million people develop acute pulmonary tuberculosis (TB) each year and about 1.5 million people worldwide die from this infection. Thus, developing vaccines to prevent active TB disease remains a priority. This article discusses recent progress in the development of new vaccines against TB and focusses on the main requirements for development of improved vaccines against Mycobacterium tuberculosis (M. tb). Over the last two decades, significant progress has been made in TB vaccine development, and some TB vaccine candidates have currently completed a phase III clinical trial. The potential public health benefits of these vaccines are possible, but it will need much more effort, including new global governance investment on this research. This investment would certainly be less than the annual global financial toll of TB treatment.

  6. Vaccination Against Tuberculosis With Whole-Cell Mycobacterial Vaccines.

    PubMed

    Scriba, Thomas J; Kaufmann, Stefan H E; Henri Lambert, Paul; Sanicas, Melvin; Martin, Carlos; Neyrolles, Olivier

    2016-09-01

    Live attenuated and killed whole-cell vaccines (WCVs) offer promising vaccination strategies against tuberculosis. A number of WCV candidates, based on recombinant bacillus Calmette-Guerin (BCG), attenuated Mycobacterium tuberculosis, or related mycobacterial species are in various stages of preclinical or clinical development. In this review, we discuss the vaccine candidates and key factors shaping the development pathway for live and killed WCVs and provide an update on progress.

  7. Safety of Japanese encephalitis live attenuated vaccination in post-marketing surveillance in Guangdong, China, 2005-2012.

    PubMed

    Liu, Yu; Lin, Hualiang; Zhu, Qi; Wu, Chenggang; Zhao, Zhanjie; Zheng, Huizhen

    2014-03-26

    We reviewed the adverse events following immunization of live attenuated Japanese encephalitis vaccine in Guangdong Province, China. During the period of 2005-2012, 23 million doses of live attenuated Japanese encephalitis vaccine were used and 1426 adverse events were reported (61.24 per million doses); of which, 570 (40%) were classified as allergic reactions (24.48 per million doses), 31 (2%) were neurologic events (1.33 per million doses), and 36 (2.5%) were diagnosed as serious adverse events (1.55 per million doses). This study suggests that the JEV-L has a reasonable safety profile, most adverse events are relatively mild, with relatively rare neurologic events being observed.

  8. Development of House Dust Mite Vaccine.

    PubMed

    Zhang, Qiuxiang; Ai, Chunqing

    2016-01-01

    Mucosal vaccine based on lactic acid bacteria is an attractive strategy for prevention and treatment of allergic diseases. Here we describe the development of recombinant Lactococcus lactis expressing house dust mite (HDM) allergen as an oral vaccine. The major HDM allergen Der p2 is first codon optimized and synthesized to achieve the maximum expression level in L. lactis. After double digested by NcoI and XbaI, the derp2 fragment is ligated to the same double-digested pNZ8148 vector. The ligation is transformed to L. lactis NZ9000 and correct transformant is verified by sequencing. Western blot analysis is employed to confirm Derp2 expression in L. lactis after nisin induction.

  9. Progress toward the development of universal influenza vaccines.

    PubMed

    Hoft, Daniel F; Belshe, Robert B

    2014-01-01

    Influenza remains a major problem causing significant morbidity and mortality annually and periodic pandemics with the potential for 10-100 fold increased mortality. Conventional vaccines can be highly effective if generated each year to match currently circulating viruses. Ongoing research focuses on producing cross-protective vaccines that induce T cell and/ or antibody responses specific for highly conserved viral epitopes. The Saint Louis University Center for Vaccine Development (SLUCVD) is highly engaged in multiple efforts to generate universally relevant influenza vaccines.

  10. Immune interference after sequential alphavirus vaccine vaccinations.

    PubMed

    Pittman, Phillip R; Liu, Ching-Tong; Cannon, Timothy L; Mangiafico, Joseph A; Gibbs, Paul H

    2009-08-06

    We compared the effect of order of administration of investigational alphavirus vaccines on neutralizing antibody response. Volunteers who received the inactivated eastern and western equine encephalitis (EEE and WEE) vaccines before live attenuated Venezuelan (VEE) vaccine had significantly lower rates of antibody response than those receiving VEE vaccine before EEE and WEE vaccines (66.7% vs. 80.6%; p=0.026). The odds of having a VEE antibody non-response among those initially receiving EEE and WEE vaccines, adjusted for gender, were significant (odds ratio [OR]=2.20; 95% CI=1.2-4.1 [p=0.0145]) as were the odds of non-response among females adjusted for group (OR=1.81; 95% CI=1.2-2.7 [p=0.0037]). Antibody interference and gender effect have major implications for vaccine strategy among those receiving multiple alphavirus vaccines and those developing next generation vaccines for these threats.

  11. Tomorrow's vector vaccines for small ruminants.

    PubMed

    Kyriakis, C S

    2015-12-14

    Inactivated and attenuated vaccines have contributed to the control or even the eradication of significant animal pathogens. However, these traditional vaccine technologies have limitations and disadvantages. Inactivated vaccines lack efficacy against certain pathogens, while attenuated vaccines are not always as safe. New technology vaccines, namely DNA and recombinant viral vector vaccines, are being developed and tested against pathogens of small ruminants. These vaccines induce both humoral and cellular immune responses, are safe to manufacture and use and can be utilized in strategies for differentiation of infected from vaccinated animals. Although there are more strict regulatory requirements for the safety standards of these vaccines, once a vaccine platform is evaluated and established, effective vaccines can be rapidly produced and deployed in the field to prevent spread of emerging pathogens. The present article offers an introduction to these next generation technologies and examples of vaccines that have been tested against important diseases of sheep and goats.

  12. Global Vaccine and Immunization Research Forum: Opportunities and challenges in vaccine discovery, development, and delivery.

    PubMed

    Ford, Andrew Q; Touchette, Nancy; Hall, B Fenton; Hwang, Angela; Hombach, Joachim

    2016-03-18

    The World Health Organization, the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, and the Bill & Melinda Gates Foundation convened the first Global Vaccine and Immunization Research Forum (GVIRF) in March 2014. This first GVIRF aimed to track recent progress of the Global Vaccine Action Plan research and development agenda, identify opportunities and challenges, promote partnerships in vaccine research, and facilitate the inclusion of all stakeholders in vaccine research and development. Leading scientists, vaccine developers, and public health officials from around the world discussed scientific and technical challenges in vaccine development, research to improve the impact of immunization, and regulatory issues. This report summarizes the discussions and conclusions from the forum participants.

  13. Status of vaccine research and development of vaccines for herpes simplex virus.

    PubMed

    Johnston, Christine; Gottlieb, Sami L; Wald, Anna

    2016-06-03

    Herpes simplex virus type-1 (HSV-1) and -2 (HSV-2) are highly prevalent global pathogens which commonly cause recurrent oral and genital ulcerations. Less common but more serious complications include meningitis, encephalitis, neonatal infection, and keratitis. HSV-2 infection is a significant driver of the HIV epidemic, increasing the risk of HIV acquisition 3 fold. As current control strategies for genital HSV-2 infection, including antiviral therapy and condom use, are only partially effective, vaccines will be required to reduce infection. Both preventive and therapeutic vaccines for HSV-2 are being pursued and are in various stages of development. We will provide an overview of efforts to develop HSV-2 vaccines, including a discussion of the clinical need for an HSV vaccine, and status of research and development with an emphasis on recent insights from trials of vaccine candidates in clinical testing. In addition, we will touch upon aspects of HSV vaccine development relevant to low and middle income countries.

  14. African horse sickness in The Gambia: circulation of a live-attenuated vaccine-derived strain.

    PubMed

    Oura, C A L; Ivens, P A S; Bachanek-Bankowska, K; Bin-Tarif, A; Jallow, D B; Sailleau, C; Maan, S; Mertens, P C; Batten, C A

    2012-03-01

    African horse sickness virus serotype 9 (AHSV-9) has been known for some time to be circulating amongst equids in West Africa without causing any clinical disease in indigenous horse populations. Whether this is due to local breeds of horses being resistant to disease or whether the AHSV-9 strains circulating are avirulent is currently unknown. This study shows that the majority (96%) of horses and donkeys sampled across The Gambia were seropositive for AHS, despite most being unvaccinated and having no previous history of showing clinical signs of AHS. Most young horses (<3 years) were seropositive with neutralizing antibodies specific to AHSV-9. Eight young equids (<3 years) were positive for AHSV-9 by serotype-specific RT-PCR and live AHSV-9 was isolated from two of these horses. Sequence analysis revealed the presence of an AHSV-9 strain showing 100% identity to Seg-2 of the AHSV-9 reference strain, indicating that the virus circulating in The Gambia was highly likely to have been derived from a live-attenuated AHSV-9 vaccine strain.

  15. Oral multicomponent DNA vaccine delivered by attenuated Salmonella elicited immunoprotection against American trypanosomiasis.

    PubMed

    Cazorla, Silvia I; Matos, Marina N; Cerny, Natacha; Ramirez, Carolina; Alberti, Andrés Sanchez; Bivona, Augusto E; Morales, Celina; Guzmán, Carlos A; Malchiodi, Emilio L

    2015-03-01

    We have reported that attenuated Salmonella (S) carrying plasmids encoding the cysteine protease cruzipain (Cz) protects against Trypanosoma cruzi infection. Here, we determined whether immunoprotection could be improved by the oral coadministration of 3 Salmonella carrying the plasmids that encode the antigens Cz, Tc52, and Tc24. SCz+STc52+STc24-immunized mice presented an increased antibody response against each antigen compared with those in the single antigen-immunized groups, as well as higher trypomastigotes antibody-mediated lyses and cell invasion inhibition compared with controls. SCz+STc52+STc24-immunized and -challenged mice rendered lower parasitemia. Weight loss after infection was detected in all mice except those in the SCz+STc52+STc24 group. Moreover, cardiomyopathy-associated enzyme activity was significantly lower in SCz+STc24+STc52-immunized mice compared with controls. Few or no abnormalities were found in muscle tissues of SCz+STc24+STc52-immunized mice, whereas controls presented with inflammatory foci, necrosis, and amastigote nests. We conclude that a multicomponent approach that targets several invasion and metabolic mechanisms improves protection compared with single-component vaccines.

  16. Impact of BRICS’ investment in vaccine development on the global vaccine market

    PubMed Central

    Milstien, Julie; Schmitt, Sarah

    2014-01-01

    Abstract Brazil, the Russian Federation, India, China and South Africa – the countries known as BRICS – have made considerable progress in vaccine production, regulation and development over the past 20 years. In 1993, all five countries were producing vaccines but the processes used were outdated and non-standardized, there was little relevant research and there was negligible international recognition of the products. By 2014, all five countries had strong initiatives for the development of vaccine technology and had greatly improved their national regulatory capacity. South Africa was then the only BRICS country that was not completely producing vaccines. South Africa is now in the process of re-establishing its own vaccine production and passing beyond the stage of simply importing, formulating and filling vaccine bulks. Changes in the public sector’s price per dose of selected vaccines, the global market share represented by products from specific manufacturers, and the attractiveness, for multinational companies, of partnership and investment opportunities in BRICS companies have all been analysed. The results indicate that the BRICS countries have had a major impact on vaccine price and availability, with much of that impact attributable to the output of Indian vaccine manufacturers. China is expected to have a greater impact soon, given the anticipated development of Chinese vaccine manufacturers in the near future. BRICS’ accomplishments in the field of vaccine development are expected to reshape the global vaccine market and accelerate access to vaccines in the developing world. The challenge is to turn these expectations into strategic actions and practical outcomes. PMID:24940018

  17. Generation of an attenuated H5N1 avian influenza virus vaccine with all eight genes from avian viruses.

    PubMed

    Shi, Huoying; Liu, Xiu Fan; Zhang, Xiaorong; Chen, Sujuan; Sun, Lei; Lu, Jianhong

    2007-10-16

    In the face of disease outbreaks in poultry and the potential pandemic threat to humans caused by the highly pathogenic avian influenza viruses (HPAIVs) of H5N1 subtype, improvement in biosecurity and the use of inactivated vaccines are two main options for the control of this disease. Vaccine candidates of influenza A viruses of H5N1 subtype have been generated in several laboratories by plasmid-based reverse genetics with hemagglutinin (HA) and neuraminidase (NA) genes from the epidemic strains of avian viruses in a background of internal genes from the vaccine donor strain of human strains, A/Puerto Rico/8/34 (PR8). These reassortant viruses containing genes from both avian and human viruses might impose biosafety concerns, also may be do if C4/F AIV would be a live attenuated vaccine or cold-adaptive strain vaccine. In order to generate better and safer vaccine candidate viruses, we genetically constructed attenuated reassortant H5N1 influenza A virus, designated as C4/F AIV, by plasmid-based reverse genetics with all eight genes from the avian strains. The C4/F AIV virus contained HA and NA genes from an epidemic strain A/Chicken/Huadong/04 (H5N1) (C4/H5N1) in a background of internal genes derived from a low pathogenic strain of A/Chicken/F/98(H9N2). The reassortant virus was attenuated by removal of the multibasic amino acid motif in the HA gene by mutation and deletion (from PQRERRRKKR (downward arrow) G to PQIETR (downward arrow) G). The intravenous pathogenicity index (IVPI) of C4/F AIV virus was 0, whereas that of the donor virus C4/H5N1 was 3.0. The virus HA titer of C4/H5N1 in the allantoic fluid from infected embryonated eggs was as high as 1:2048. The inactivated vaccine prepared from the reassortant virus C4/F AIV-induced high HI titer in vaccinated chickens and gave 100% protection when challenged with highly pathogenic avian influenza virus of H5N1 subtype.

  18. Advances in neglected tropical disease vaccines: Developing relative potency and functional assays for the Na-GST-1/Alhydrogel hookworm vaccine.

    PubMed

    Brelsford, Jill B; Plieskatt, Jordan L; Yakovleva, Anna; Jariwala, Amar; Keegan, Brian P; Peng, Jin; Xia, Pengjun; Li, Guangzhao; Campbell, Doreen; Periago, Maria Victoria; Correa-Oliveira, Rodrigo; Bottazzi, Maria Elena; Hotez, Peter J; Diemert, David; Bethony, Jeffrey M

    2017-02-01

    A new generation of vaccines for the neglected tropical diseases (NTDs) have now advanced into clinical development, with the Na-GST-1/Alhydrogel Hookworm Vaccine already being tested in Phase 1 studies in healthy adults. The current manuscript focuses on the often overlooked critical aspects of NTD vaccine product development, more specifically, vaccine stability testing programs. A key measure of vaccine stability testing is "relative potency" or the immunogenicity of the vaccine during storage. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed by attenuation or inactivation of the pathogen (Necator americanus), so conventional methods for measuring relative potency are not relevant for this investigational product. Herein, we describe a novel relative potency testing program and report for the first time on the clinical lot of this NTD vaccine during its first 60 months of storage at 2-8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. While 90% inhibition of the catalytic activity of Na-GST-1 was achieved in animals immunized with Na-GST-1/Alhydrogel, lower levels of inhibition were observed in immunized humans. Moreover, anti-Na-GST-1 antibodies from volunteers in non-hookworm endemic areas were better able to inhibit catalytic activity than anti-Na-GST-1 antibodies from volunteers resident in hookworm endemic areas. The results described herein provide the critical tools for the product development of NTD vaccines.

  19. Advances in neglected tropical disease vaccines: Developing relative potency and functional assays for the Na-GST-1/Alhydrogel hookworm vaccine

    PubMed Central

    Brelsford, Jill B.; Plieskatt, Jordan L.; Yakovleva, Anna; Jariwala, Amar; Keegan, Brian P.; Peng, Jin; Xia, Pengjun; Li, Guangzhao; Campbell, Doreen; Periago, Maria Victoria; Correa-Oliveira, Rodrigo; Bottazzi, Maria Elena; Hotez, Peter J.

    2017-01-01

    A new generation of vaccines for the neglected tropical diseases (NTDs) have now advanced into clinical development, with the Na-GST-1/Alhydrogel Hookworm Vaccine already being tested in Phase 1 studies in healthy adults. The current manuscript focuses on the often overlooked critical aspects of NTD vaccine product development, more specifically, vaccine stability testing programs. A key measure of vaccine stability testing is "relative potency" or the immunogenicity of the vaccine during storage. As with most NTD vaccines, the Na-GST-1/Alhydrogel Hookworm Vaccine was not developed by attenuation or inactivation of the pathogen (Necator americanus), so conventional methods for measuring relative potency are not relevant for this investigational product. Herein, we describe a novel relative potency testing program and report for the first time on the clinical lot of this NTD vaccine during its first 60 months of storage at 2–8°C. We also describe the development of a complementary functional assay that measures the ability of IgG from animals or humans immunized with Na-GST-1/Alhydrogel to neutralize this important hookworm enzyme. While 90% inhibition of the catalytic activity of Na-GST-1 was achieved in animals immunized with Na-GST-1/Alhydrogel, lower levels of inhibition were observed in immunized humans. Moreover, anti-Na-GST-1 antibodies from volunteers in non-hookworm endemic areas were better able to inhibit catalytic activity than anti-Na-GST-1 antibodies from volunteers resident in hookworm endemic areas. The results described herein provide the critical tools for the product development of NTD vaccines. PMID:28192438

  20. Challenges facing the development of cancer vaccines.

    PubMed

    Fishman, Mayer

    2014-01-01

    Just like any other effective immunization in medicine, cancer vaccines need to have antigens with particular specificity and immunostimulatory features, the immune responses to be elicited in the body, and therapeutic effect-regression or prevention of the cancer-must be meaningful and clinically observable. There are many choices for cancer antigens, such as tissue-specific proteins, cancer-specific proteins, class I- or class II-restricted peptides derived from those, or in situ and whole-cell-derived products are some examples. Another translational issue is that cancer patients are heterogeneous with respect to the extent to which the immune system is already activated with potential to impact the tumor growth or, conversely, the extent to which the immune system has been impaired through a prior and ongoing interaction with the tumor. Conventional or immunologic tests have potential to define a subset of patients with better chance or response, so that particular vaccines can be tested. Treatment of cancer patients is expensive, and trials are slow. To meet these challenges in practical terms will require not only careful scientific technical work for product development, coordination with clinicians to define patient subsets with diseases that can show responses, but also a comprehensive, practical implementation so that we can unlock the full potential of anticancer vaccines.

  1. Newcastle Disease Virus as a Vaccine Vector for Development of Human and Veterinary Vaccines

    PubMed Central

    Kim, Shin-Hee; Samal, Siba K.

    2016-01-01

    Viral vaccine vectors have shown to be effective in inducing a robust immune response against the vaccine antigen. Newcastle disease virus (NDV), an avian paramyxovirus, is a promising vaccine vector against human and veterinary pathogens. Avirulent NDV strains LaSota and B1 have long track records of safety and efficacy. Therefore, use of these strains as vaccine vectors is highly safe in avian and non-avian species. NDV replicates efficiently in the respiratory track of the host and induces strong local and systemic immune responses against the foreign antigen. As a vaccine vector, NDV can accommodate foreign sequences with a good degree of stability and as a RNA virus, there is limited possibility for recombination with host cell DNA. Using NDV as a vaccine vector in humans offers several advantages over other viral vaccine vectors. NDV is safe in humans due to host range restriction and there is no pre-existing antibody to NDV in the human population. NDV is antigenically distinct from common human pathogens. NDV replicates to high titer in a cell line acceptable for human vaccine development. Therefore, NDV is an attractive vaccine vector for human pathogens for which vaccines are currently not available. NDV is also an attractive vaccine vector for animal pathogens. PMID:27384578

  2. Newcastle Disease Virus as a Vaccine Vector for Development of Human and Veterinary Vaccines.

    PubMed

    Kim, Shin-Hee; Samal, Siba K

    2016-07-04

    Viral vaccine vectors have shown to be effective in inducing a robust immune response against the vaccine antigen. Newcastle disease virus (NDV), an avian paramyxovirus, is a promising vaccine vector against human and veterinary pathogens. Avirulent NDV strains LaSota and B1 have long track records of safety and efficacy. Therefore, use of these strains as vaccine vectors is highly safe in avian and non-avian species. NDV replicates efficiently in the respiratory track of the host and induces strong local and systemic immune responses against the foreign antigen. As a vaccine vector, NDV can accommodate foreign sequences with a good degree of stability and as a RNA virus, there is limited possibility for recombination with host cell DNA. Using NDV as a vaccine vector in humans offers several advantages over other viral vaccine vectors. NDV is safe in humans due to host range restriction and there is no pre-existing antibody to NDV in the human population. NDV is antigenically distinct from common human pathogens. NDV replicates to high titer in a cell line acceptable for human vaccine development. Therefore, NDV is an attractive vaccine vector for human pathogens for which vaccines are currently not available. NDV is also an attractive vaccine vector for animal pathogens.

  3. Chikungunya virus vaccines: Current strategies and prospects for developing plant-made vaccines.

    PubMed

    Salazar-González, Jorge A; Angulo, Carlos; Rosales-Mendoza, Sergio

    2015-07-17

    Chikungunya virus is an emerging pathogen initially found in East Africa and currently spread into the Indian Ocean Islands, many regions of South East Asia, and in the Americas. No licensed vaccines against this eminent pathogen are available and thus intensive research in this field is a priority. This review presents the current scenario on the developments of Chikungunya virus vaccines and identifies the use of genetic engineered plants to develop attractive vaccines. The possible avenues to develop plant-made vaccines with distinct antigenic designs and expression modalities are identified and discussed considering current trends in the field.

  4. Risks associated with the use of live-attenuated vaccine poliovirus strains and the strategies for control and eradication of paralytic poliomyelitis.

    PubMed

    Pliaka, Vaia; Kyriakopoulou, Zaharoula; Markoulatos, Panayotis

    2012-05-01

    The Global Polio Eradication Initiative was launched in 1988 with the aim to eliminate paralytic poliomyelitis. Two effective vaccines are available: inactivated polio vaccine (IPV) and oral polio vaccine (OPV). Since 1964, OPV has been used instead of IPV in most countries due to several economic and biological advantages. However, in rare cases, the live-attenuated Sabin strains of OPV revert to neurovirulence and cause vaccine-associated paralytic poliomyelitis in vaccinees or lead to emergence of vaccine-derived poliovirus strains. Attenuating mutations and recombination events have been associated with the reversion of vaccine strains to neurovirulence. The substitution of OPV with an improved new-generation IPV and the availability of new specific drugs against polioviruses are considered as future strategies for outbreak control and the eradication of paralytic poliomyelitis worldwide.

  5. Role of Metallic Nanoparticles in Vaccinology: Implications for Infectious Disease Vaccine Development

    PubMed Central

    Marques Neto, Lázaro Moreira; Kipnis, André; Junqueira-Kipnis, Ana Paula

    2017-01-01

    Subunit vaccines are safer but less immunogenic than live-attenuated vaccines or whole cell inactivated vaccines. Adjuvants are used to enhance and modulate antigen (Ag) immunogenicity, aiming to induce a protective and long-lasting immune response. Several molecules and formulations have been studied for their adjuvanticity, but only seven have been approved to formulate human vaccines. Metallic nanoparticles (MeNPs), particularly those containing gold and iron oxides, are widely used in medicine for diagnosis and therapy and have been used as carriers for drugs and vaccines. However, little is known about the immune response elicited by MeNPs or about their importance in the development of new vaccines. There is evidence that these particles display adjuvant characteristics, promoting cell recruitment, antigen-presenting cell activation, cytokine production, and inducing a humoral immune response. This review focuses on the characteristics of MeNPs that could facilitate the induction of a cellular immune response, particularly T-helper 1 and T-helper 17, and their potential functions as adjuvants for subunit vaccines. PMID:28337198

  6. Vaccination of Volunteers with Low-Dose, Live-Attenuated, Dengue Viruses Leads to Serotype-specific Immunologic and Virologic Profiles

    PubMed Central

    Lindow, Janet C.; Durbin, Anna P.; Whitehead, Stephen S.; Pierce, Kristen K.; Carmolli, Marya P.; Kirkpatrick, Beth D.

    2013-01-01

    There are currently no vaccines or therapeutics to prevent dengue disease which ranges in severity from asymptomatic infections to life-threatening illness. The National Institute of Allergy and Infectious Diseases (NIAID) Division of Intramural Research has developed live, attenuated vaccines to each of the four dengue serotypes (DENV-1 – DENV-4). Two doses (10 PFU and 1000 PFU) of three monovalent vaccines were tested in human clinical trials to compare safety and immunogenicity profiles. DEN4Δ30 had been tested previously at multiple doses. The three dengue vaccine candidates tested (DEN1Δ30, DEN2/4Δ30, and DEN3Δ30/31) were very infectious, each with a Human Infectious Dose 50% ≤ 10 PFU. Further, infectivity rates ranged from 90 −100% regardless of dose, excepting DEN2/4Δ30 which dropped from 100% at the 1000 PFU dose to 60% at the 10 PFU dose. Mean geometric peak antibody titers did not differ significantly between doses for DEN1Δ30 (92 ± 19 vs. 214 ± 97, p = 0.08); however, significant differences were observed between the 10 PFU and 1000 PFU doses for DEN2/4Δ30, 19 ± 9 vs. 102 ± 25 (p = 0.001), and DEN3Δ30/31, 119 ± 135 vs. 50 ± 50 (p=0.046). No differences in the incidences of rash, neutropenia, or viremia were observed between doses for any vaccines, though the mean peak titer of viremia for DEN1Δ30 was higher at the 1000 PFU dose (0.5 ± 0 vs. 1.1 ± 0.1, p = 0.007). These data demonstrate that atarget dose of 1000 PFU for inclusi