A novel fiber-2-edited live attenuated vaccine candidate against the highly pathogenic serotype 4 fowl adenovirus

AbstractRecently, the outbreaks of hydropericardium-hepatitis syndrome (HHS) caused by the highly pathogenic fowl adenovirus serotype 4 (FAdV-4) have resulted in huge economic losses to the poultry industry globally. Although several inactivated or subunit vaccines have been developed against FAdV-4, live-attenuated vaccines for FAdV-4 are rarely reported. In this study, a recombinant virus FA4-EGFP expressing EGFP-Fiber-2 fusion protein was generated by the CRISPR/Cas9 technique. Although FA4-EGFP shows slightly lower replication ability than the wild type (WT) FAdV-4, FA4-EGFP was significantly attenuated in vivo compared with the WT FAdV-4. Chickens infected with FA4-EGFP did not show any clinical signs, and all survived to 14 day post-infection (dpi), whereas those infected with FAdV-4 showed severe clinical signs with HHS and all died at 4 dpi. Besides, the inoculation of FA4-EGFP in chickens provided efficient protection against lethal challenge with FAdV-4. Compared with an inactivated vaccine, FA4-EGFP induced neutralizing antibodies with higher titers earlier. All these data not only provide a live-attenuated vaccine candidate against the highly pathogenic FAdV-4 but also give a potential insertion site for developing FAdV-4-based vaccine vectors for delivering foreign antigens.

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A Novel Fiber-1-Edited and Highly Attenuated Recombinant Serotype 4 Fowl Adenovirus Confers Efficient Protection Against Lethal Challenge

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.759418 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yaru Mu ◽

Quan Xie ◽

Weikang Wang ◽

Hao Lu ◽

Mingjun Lian ◽

...

Keyword(s):

Recombinant Virus ◽

Animal Studies ◽

Insertion Site ◽

Economic Losses ◽

Lethal Challenge ◽

Live Attenuated Vaccine ◽

Hydropericardium Syndrome ◽

Fowl Adenovirus ◽

Efficient Protection

Currently, a fatal disease of hepatitis-hydropericardium syndrome (HHS) caused by serotype 4 fowl adenovirus (FAdV-4) has spread worldwide and resulted in tremendous economic losses to the poultry industry. Various vaccines against FAdV-4 were developed to control the disease; however, few live-attenuated vaccines were available. In this study, we targeted the N-terminal of fiber-1 and rescued a recombinant virus FAdV4-RFP_F1 expressing the fusion protein of RFP and Fiber-1 based on the CRISPR/Cas9 technique. In vitro studies showed that FAdV4-RFP_F1 replicated slower than the wild type FAdV-4, but the peak viral titer of FAdV4-RFP_F1 could still reach 107.0 TCID50/ml with high stability in LMH cells. Animal studies found that FAdV4-RFP_F1 not only was highly attenuated to the 2-week-old SPF chickens, but could also provide efficient protection against lethal challenge of FAdV-4. All these demonstrate that the recombinant virus FAdV4-RFP_F1 could be as an efficient live-attenuated vaccine candidate for FAdV-4, and the N-terminal of fiber-1 could be as a potential insertion site for expressing foreign genes to develop FAdV-4-based vaccine.

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Deletion of A137R gene from the pandemic strain of African swine fever virus is attenuated and offers protection against virulent pandemic virus

Journal of Virology ◽

10.1128/jvi.01139-21 ◽

2021 ◽

Author(s):

Douglas P. Gladue ◽

Elizabeth Ramirez-Medina ◽

Elizabeth Vuono ◽

Ediane Silva ◽

Ayushi Rai ◽

...

Keyword(s):

East Asia ◽

Central Europe ◽

Vaccine Candidate ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Economic Losses ◽

Live Attenuated Vaccine ◽

Attenuated Vaccine ◽

Highly Virulent

African swine fever virus (ASFV) is causing a devastating pandemic in domestic and wild swine within an extended geographical area from Central Europe to East Asia resulting in economic losses for the regional swine industry. There are no commercial vaccines, therefore disease control relies on identification and culling of infected animals. We report here that the deletion of the ASFV gene A137R from the highly virulent ASFV-Georgia2010 (ASFV-G) isolate induces a significant attenuation of virus virulence in swine. A recombinant virus lacking the A137R gene, ASFV-G-ΔA137R, was developed to assess the role of this gene in ASFV virulence in domestic swine. Animals inoculated intramuscularly with 10 2 HAD 50 of ASFV-G-ΔA137R remained clinically healthy during the 28 day observational period. All animals inoculated with ASFV-G-ΔA137R had medium to high viremia titers and developed a strong virus-specific antibody response. Importantly, all ASFV-G-ΔA137R-inoculated animals were protected when challenged with the virulent parental strain ASFV-G. No evidence of replication of challenge virus was observed in the ASFV-G-ΔA137R-inoculated animals. Therefore, ASFV-G-ΔA137R is a novel potential live attenuated vaccine candidate and one of the few experimental vaccine strains reported to induce protection against the highly virulent ASFV Georgia virus that is the cause of the current Eurasian pandemic. Importance: No commercial vaccine is available to prevent African swine fever. The ASF pandemic caused by ASFV Georgia2007 (ASFV-G) is seriously affecting pork production in a contiguous area from Central Europe to East Asia. Here we report the rational development of a potential live attenuated vaccine strain by deleting a virus-specific gene, A137R, from the genome of ASFV-G. The resulting virus presented a completely attenuated phenotype and, importantly, animals infected with this genetically modified virus were protected from developing ASF after challenge with the virulent parental virus. ASFV-G-ΔA137R confers protection even at low doses (10 2 HAD 50 ) demonstrating its potential as a vaccine candidate. Therefore, ASFV-G-ΔA137R is a novel experimental ASF vaccine protecting pigs from the epidemiologically relevant ASFV Georgia isolate.

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Live attenuated SARS-CoV-2 vaccine candidate: Protective immunity without serious lung lesions in Syrian hamsters

10.1101/2021.02.15.430863 ◽

2021 ◽

Author(s):

Shinya Okamura ◽

Akiho Kashiwabara ◽

Hidehiko Suzuki ◽

Shiori Ueno ◽

Paola Miyazato ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Candidate ◽

Nonstructural Protein ◽

Wild Type Virus ◽

Temperature Sensitive ◽

Live Attenuated Vaccine ◽

Syrian Hamsters ◽

Attenuated Vaccine

AbstractVarious COVID-19 vaccine candidates are currently under clinical trial. However, no live attenuated vaccine has been developed yet, despite their generally high efficacy. Here, we established temperature-sensitive mutant strains of SARS-CoV-2, whose growth was significantly slower than that of the parent strain at 37°C. One of the strains, A50-18, which presented mutations in nonstructural protein 14, did not replicate at all at 37°C in vitro. In vivo experiments demonstrated that this strain replicated inefficiently in the lungs of Syrian hamsters, and intra-nasal inoculation induced sufficient anti-SARS-CoV-2-neutralizing antibodies to protect against wild type virus infection. These results suggest that the A50-18 strain could be a promising live attenuated vaccine candidate against SARS-CoV-2.One Sentence SummaryA live attenuated virus provided immunity against SARS-CoV-2 in an animal model, making it a promising vaccine candidate.

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Efficacy of a live attenuated highly pathogenic PRRSV vaccine against a NADC30-like strain challenge: implications for ADE of PRRSV

BMC Veterinary Research ◽

10.1186/s12917-021-02957-z ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Xin-xin Chen ◽

Xinyu Zhou ◽

Tengda Guo ◽

Songlin Qiao ◽

Zhenhua Guo ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Molecular Mechanisms ◽

Clinical Signs ◽

Bodyweight Gain ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Experimental Conditions ◽

Highly Pathogenic ◽

Highly Pathogenic Prrsv

Abstract Background Porcine reproductive and respiratory syndrome virus (PRRSV) infection can cause severe reproductive failure in sows and respiratory distress in pigs of all ages, leading to major economic losses. To date, there are still no effective strategies to prevent and control PRRSV. Antibody-dependent enhancement (ADE), a phenomenon in which preexisting non-neutralizing antibodies or sub-neutralizing antibodies facilitate virus entry and replication, may be a significant obstacle in the development of effective vaccines for many viruses, including PRRSV. However, the contribution of ADE to PRRSV infection remains controversial, especially in vivo. Whether attenuated PRRSV vaccines prevent or worsen subsequent disease in pigs infected by novel PRRSV strains requires more research. In the present study, in vivo experiments were conducted to evaluate ADE under different immune statuses, which were produced by waiting different lengths of time after vaccination with a commercially available attenuated highly pathogenic PRRSV (HP-PRRSV) vaccine (JXA1-R) before challenging the pigs with a novel heterologous NADC30-like strain. Results Piglets that were vaccinated before being challenged with PRRSV exhibited lower mortality rates, lower body temperatures, higher bodyweight gain, and lower viremia. These results demonstrate that vaccination with JXA1-R alleviated the clinical signs of PRRSV infection in all vaccinated groups. Conclusions The obtained data indicate that the attenuated vaccine test here provided partial protection against the NADC30-like strain HNhx. No signs of enhanced PRRSV infection were observed under the applied experimental conditions. Our results provide some insight into the molecular mechanisms underlying vaccine-induced protection or enhancement in PRRSV.

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Construction of a Quadruple Gene-deleted Vaccine Confers Complete Protective Immunity Against Emerging PRV Variant Challenge in Piglets

10.21203/rs.3.rs-985687/v1 ◽

2021 ◽

Author(s):

Leqiang Sun ◽

Yajie Tang ◽

Keji Yan ◽

Huawei Zhang

Keyword(s):

Pseudorabies Virus ◽

Clinical Signs ◽

Economic Losses ◽

Swine Industry ◽

Live Attenuated Vaccine ◽

Specific Antibodies ◽

Variant Strain ◽

Attenuated Vaccine ◽

Suckling Piglets ◽

Full Protection

Abstract Background: Pseudorabies virus (PRV) causes Aujeszky’s disease or pseudorabies (PR) in pigs worldwide, which leads to heavy economic losses to the swine industry. Pigs are the natural host, meanwhile, animals such as dogs, cats, foxes, rabbits, cattle and sheep are susceptible to infection. In 2011, the emerging PRV variant led to the outbreak of PR in Bar-tha-K61-vaccinated pigs. The PR outbreaks demonstrated that the Bartha-K61 vaccine did not provide full protection against the emerging PRV variant. It is widely believed that PRV live-attenuated vaccines could control PRV infection. Methods: In this study, we developed a novel PRV live-attenuated vaccine by deleting its gI, gE, US9, and US2 genes through CRISPR/Cas9, which was named PRV GDFS-delgI/gE/US9/US2.Results: Safety experiments confirmed that PRV GDFS-delgI/gE/US9/US2 was safe for 5 to 7-day-old suckling piglets. Piglets immunized with the PRV GDFS-delgI/gE/US9/US2 vaccine did not produce PRV gE-specific antibodies but could generate PRV gB-specific antibodies and high neutralizing titers against the PRV GDFS strain (variant PRV strain) or PRV Ea strain (older PRV strain). After challenge with the emerging PRV GDFS variant, none of the piglets immunized with the PRV GDFS-delgI/gE/US9/US2 vaccine showed any clinical signs, and their rectal temperatures were normal. Moreover, the autopsy and histopathological analyses revealed that the piglets in the PRV GDFS-delgI/gE/US9/US2 vaccine group did not show apparent gross or pathological lesions. Furthermore, the piglets in the PRV GDFS-delgI/gE/US9/US2 vaccine groups did not present weight loss. According to the criteria of the OIE terrestrial manual, the results of the experiment confirmed that the PRV GDFS-delgI/gE/US9/US2 vaccine could provide full protection against the emerging PRV variant strain in piglets. Conclusions: The PRV GDFS-delgI/gE/US9/US2 strain is a potential new live-attenuated vaccine against emerging PRV variant strain infections in China.

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Immunogenicity, Genetic Stability, and Protective Efficacy of a Recombinant, Chimeric Yellow Fever-Japanese Encephalitis Virus (ChimeriVax-JE) as a Live, Attenuated Vaccine Candidate against Japanese Encephalitis

Virology ◽

10.1006/viro.1999.9695 ◽

1999 ◽

Vol 257 (2) ◽

pp. 363-372 ◽

Cited By ~ 123

Author(s):

F. Guirakhoo ◽

Z.-X. Zhang ◽

T.J. Chambers ◽

S. Delagrave ◽

J. Arroyo ◽

...

Keyword(s):

Japanese Encephalitis Virus ◽

Yellow Fever ◽

Japanese Encephalitis ◽

Genetic Stability ◽

Vaccine Candidate ◽

Protective Efficacy ◽

Encephalitis Virus ◽

Live Attenuated Vaccine ◽

Attenuated Vaccine

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An optimized secretory expression system and immunogenicity evaluation for glycosylated gp90 of avian reticuloendotheliosis virus

Veterinary Research ◽

10.1186/s13567-020-00857-y ◽

2020 ◽

Vol 51 (1) ◽

Author(s):

Qing Pan ◽

Jing Wang ◽

Altaf Hussain ◽

Yulong Gao ◽

Hongyu Cui ◽

...

Keyword(s):

Specific Antibody ◽

Neutralizing Antibodies ◽

Vaccine Candidate ◽

Expression System ◽

Production Costs ◽

Interleukin 4 ◽

Economic Losses ◽

Structural Protein ◽

Reticuloendotheliosis Virus ◽

Secretory Expression

Abstract Reticuloendotheliosis is an important immunosuppressive disease, associated with avian reticuloendotheliosis virus (REV) infection, and causes notable economic losses worldwide. Glycoprotein gp90 is an important structural protein of REV, and considered to be the most important immunogenic antigen, which can induce neutralizing antibodies against REV. In this study, an optimized suspension culture system was developed and applied to secretory express the immunogenic surface antigen gp90. To achieve an optimal glycosylation, the gp90 was designed to secretory expressed into the supernatant of the cell culture, which also occurs in the natural protein maturation procedure of REV. Serum-free culture medium was introduced to simplify the purification process and reduce the production costs. Based on the purified glycosylated gp90, an oil-emulsion subunit REV vaccine candidate was developed and evaluated in chickens. The subunit gp90-based vaccine induced fast immune responses, high levels of antibodies (REV-specific antibody, gp90-specific antibody, and neutralizing antibody against REV), and preferential T helper 2 (Th2) (interleukin-4 secretion) not Th1 (interferon-γ secretion) response. Furthermore, the viremia induced by REV infection was significantly reduced in chickens immunized with the glycosylated gp90. Overall, an optimized secretory expression system for glycosylated gp90 was developed, and the glycosylated gp90 obtained in this study retained good immunogenicity and could be an attractive vaccine candidate to protect chickens against REV horizonal infection.

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A novel Schmallenberg virus subunit vaccine candidate protects IFNAR-/- mice against virulent SBV challenge

Scientific Reports ◽

10.1038/s41598-020-73424-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hani Boshra ◽

Gema Lorenzo ◽

Diego Charro ◽

Sandra Moreno ◽

Gabriel Soares Guerra ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Subunit Vaccine ◽

Vaccine Candidate ◽

Clinical Signs ◽

Interferon Γ ◽

Schmallenberg Virus ◽

Immune Protection ◽

Large Ruminant ◽

Economical Alternative

AbstractSchmallenberg virus (SBV), an arthropod-transmitted pathogenic bunyavirus, continues to be a threat to the European livestock industry, causing morbidity and mortality among young ruminant livestock. Here, we describe a novel SBV subunit vaccine, based on bacterially expressed SBV nucleoprotein (SBV-N) administered with a veterinary-grade Saponin adjuvant. When assayed in an IFNAR-/- mouse model, SBV-N with Saponin induced strong non-neutralizing broadly virus-reactive antibodies, decreased clinical signs, as well as significantly reduced viremia. Vaccination assays also suggest that this level of immune protection is cell mediated, as evidenced by the lack of neutralizing antibodies, as well as interferon-γ secretion observed in vitro. Therefore, based on these results, bacterially expressed SBV-N, co-administered with veterinary-grade Saponin adjuvant may serve as a promising economical alternative to current SBV vaccines, and warrant further evaluation in large ruminant animal models. Moreover, we propose that this strategy may be applicable to other bunyaviruses.

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GapA+ Mycoplasma gallisepticum ts-11 has improved vaccine characteristics

Microbiology ◽

10.1099/mic.0.046789-0 ◽

2011 ◽

Vol 157 (6) ◽

pp. 1740-1749 ◽

Cited By ~ 15

Author(s):

Pollob K. Shil ◽

Anna Kanci ◽

Glenn F. Browning ◽

Marc S. Marenda ◽

Amir H. Noormohammadi ◽

...

Keyword(s):

Antibody Response ◽

Respiratory Disease ◽

Vaccine Candidate ◽

Clinical Signs ◽

Mycoplasma Gallisepticum ◽

Specific Pathogen Free ◽

Live Attenuated Vaccine ◽

Live Attenuated Vaccines ◽

Specific Pathogen ◽

Dose Dependent

Mycoplasma gallisepticum (MG) is an important poultry pathogen that causes respiratory disease and loss of production worldwide, and is currently controlled with live attenuated vaccines. These vaccines have limitations as they vary in their pathogenicity, the protection afforded and their transmissibility, but have been shown to effectively reduce losses associated with challenge in the field. A live attenuated vaccine, ts-11, has been used for the control of M. gallisepticum in several countries. This vaccine is highly dose-dependent and the flock antibody response is weak. GapA is the primary cytadherence molecule in M. gallisepticum, and the absence of GapA expression has been observed in the vast majority of cells in the ts-11 vaccine strain. In this study the immunogenicity of a GapA+ M. gallisepticum ts-11 vaccine was investigated in specific-pathogen-free chickens. Birds vaccinated with GapA+ M. gallisepticum ts-11 were protected against clinical signs of disease following challenge with virulent M. gallisepticum, and GapA+ M. gallisepticum ts-11 was shown to be non-pathogenic and more immunogenic at a lower dose than the currently available M. gallisepticum ts-11 vaccine. Thus, GapA+ M. gallisepticum ts-11 appears to have improved potential as a vaccine candidate.

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