Recombinant Bivalent Live Vectored Vaccine Against Classical Swine Fever and HP-PRRS Revealed Adequate Heterogeneous Protection Against NADC30-Like Strain

The recombinant bivalent live vectored vaccine rPRRSV-E2 has been proved to be a favorable genetic engineering vaccine against classical swine fever (CSF) and highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS). NADC30-like strains have recently emerged in China and caused severe disease, and it is necessary to evaluate the vaccine candidate for the currently circulating viruses. This study established a good challenge model to evaluate the candidate rPRRSV-E2 vaccine in preventing infection with a representative NADC30-like strain (ZJqz21). It was shown that the challenge control piglets displayed clinical signs typical of PRRSV, including a persistent fever, dyspnea, moderate interstitial pneumonia, lymph node congestion, and viremia. In contrast, the rPRRSV-E2 vaccination significantly alleviated the clinical signs, yielded a high level of antibodies, provided adequate protection against challenge with ZJqz21, and inhibited viral shedding and the viral load in target tissues. Our results demonstrated that the recombinant bivalent live vectored vaccine strain rPRRSV-E2 can provide efficient protection against the challenge of heterologous circulating NADC30-like strain and could be a promising vaccine candidate for the swine industry.

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Analysis of Virus Population Profiles within Pigs Infected with Virulent Classical Swine Fever Viruses: Evidence for Bottlenecks in Transmission but Absence of Tissue-Specific Virus Variants

Journal of Virology ◽

10.1128/jvi.01119-20 ◽

2020 ◽

Vol 94 (19) ◽

Author(s):

Camille Melissa Johnston ◽

Ulrik Fahnøe ◽

Louise Lohse ◽

Jens Bukh ◽

Graham J. Belsham ◽

...

Keyword(s):

Classical Swine Fever Virus ◽

Population Change ◽

Virulent Strain ◽

Severe Disease ◽

Clinical Signs ◽

Classical Swine Fever ◽

Fever Virus ◽

Host Cells ◽

Virus Population ◽

Highly Virulent

ABSTRACT Classical swine fever virus (CSFV) contains a specific motif within the E2 glycoprotein that differs between strains of different virulence. In the highly virulent CSFV strain Koslov, this motif comprises residues S763/L764 in the polyprotein. However, L763/P764 represent the predominant alleles in published CSFV genomes. In this study, changes were introduced into the CSFV strain Koslov (here called vKos_SL) to generate modified CSFVs with substitutions at residues 763 and/or 764 (vKos_LL, vKos_SP, and vKos_LP). The properties of these mutant viruses, in comparison to those of vKos_SL, were determined in pigs. Each of the viruses was virulent and induced typical clinical signs of CSF, but the vKos_LP strain produced them significantly earlier. Full-length CSFV cDNA amplicons (12.3 kb) derived from sera of infected pigs were deep sequenced and cloned to reveal the individual haplotypes that contributed to the single-nucleotide polymorphism (SNP) profiles observed in the virus population. The SNP profiles for vKos_SL and vKos_LL displayed low-level heterogeneity across the entire genome, whereas vKos_SP and vKos_LP displayed limited diversity with a few high-frequency SNPs. This indicated that vKos_SL and vKos_LL exhibited a higher level of fitness in the host and more stability at the consensus level, whereas several consensus changes were observed in the vKos_SP and vKos_LP sequences, pointing to adaptation. For each virus, only a subset of the variants present within the virus inoculums were maintained in the infected pigs. No clear tissue-dependent quasispecies differentiation occurred within inoculated pigs; however, clear evidence for transmission bottlenecks to contact animals was observed, with subsequent loss of sequence diversity. IMPORTANCE The surface-exposed E2 protein of classical swine fever virus is required for its interaction with host cells. A short motif within this protein varies between strains of different virulence. The importance of two particular amino acid residues in determining the properties of a highly virulent strain of the virus has been analyzed. Each of the different viruses tested proved highly virulent, but one of them produced earlier, but not more severe, disease. By analyzing the virus genomes present within infected pigs, it was found that the viruses which replicated within inoculated animals were only a subset of those within the virus inoculum. Furthermore, following contact transmission, it was shown that a very restricted set of viruses had transferred between animals. There were no significant differences in the virus populations present in various tissues of the infected animals. These results indicate mechanisms of virus population change during transmission between animals.

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Comparison of gE/gI- and TK/gE/gI-Gene-Deleted Pseudorabies Virus Vaccines Mediated by CRISPR/Cas9 and Cre/Lox Systems

Viruses ◽

10.3390/v12040369 ◽

2020 ◽

Vol 12 (4) ◽

pp. 369

Author(s):

Jianglong Li ◽

Kui Fang ◽

Zhenxiang Rong ◽

Xinxin Li ◽

Xujiao Ren ◽

...

Keyword(s):

Immune Response ◽

Cd8 T Cells ◽

Humoral Immune Response ◽

Pseudorabies Virus ◽

Vaccine Candidate ◽

Clinical Signs ◽

Humoral Immune ◽

Viral Shedding ◽

Ifn Γ ◽

Efficacious Vaccine

Pseudorabies (PR), caused by pseudorabies virus (PRV), is an acute and febrile infectious disease in swine. To eradicate PR, a more efficacious vaccine needs to be developed. Here, the gE/gI- and TK/gE/gI-gene-deleted recombinant PRV (rGXΔgE/gI and rGXΔTK/gE/gI) are constructed through CRISPR/Cas9 and Cre/Lox systems. We found that the rGXΔTK/gE/gI was safer than rGXΔgE/gI in mice. Additionally, the effects of rGXΔgE/gI and rGXΔTK/gE/gI were further evaluated in swine. The rGXΔgE/gI and rGXΔTK/gE/gI significantly increased numbers of IFN-γ-producing CD4+ and CD8+ T-cells in swine, whereas there was no difference between rGXΔgE/gI and rGXΔTK/gE/gI. Moreover, rGXΔgE/gI and rGXΔTK/gE/gI promoted a PRV-specific humoral immune response. The PRV-specific humoral immune response induced by rGXΔgE/gI was consistent with that caused by rGXΔTK/gE/gI. After the challenge, swine vaccinated with rGXΔgE/gI and rGXΔTK/gE/gI showed no clinical signs and viral shedding. However, histopathological detection revealed that rGXΔgE/gI, not rGXΔTK/gE/gI, caused pathological lesions in brain and lung tissues. In summary, these results demonstrate that the TK/gE/gI-gene-deleted recombinant PRV was safer compared with rGXΔgE/gI in swine. The data imply that the TK/gE/gI-gene-deleted recombinant PRV may be a more efficacious vaccine candidate for the prevention of PR.

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Construction and Immunological Evaluation of an Adenoviral Vector-Based Vaccine Candidate for Lassa Fever

Viruses ◽

10.3390/v13030484 ◽

2021 ◽

Vol 13 (3) ◽

pp. 484

Author(s):

Meirong Wang ◽

Ruihua Li ◽

Yaohui Li ◽

Changming Yu ◽

Xiangyang Chi ◽

...

Keyword(s):

Adenoviral Vector ◽

Viral Infections ◽

Vaccine Candidate ◽

Severe Disease ◽

Hemorrhagic Fever ◽

Lassa Fever ◽

Lassa Virus ◽

Glycoprotein Precursor ◽

Vectored Vaccine ◽

Cellular Immune

Lassa virus (LASV) is a rodent-borne arenavirus circulating in West African regions that causes Lassa fever (LF). LF is normally asymptomatic at the initial infection stage, but can progress to severe disease with multiorgan collapse and hemorrhagic fever. To date, the therapeutic choices are limited, and there is no approved vaccine for avoiding LASV infection. Adenoviral vector-based vaccines represent an effective countermeasure against LASV because of their safety and adequate immunogenicity, as demonstrated in use against other emerging viral infections. Here, we constructed and characterized a novel Ad5 (E1-, E3-) vectored vaccine containing the glycoprotein precursor (GPC) of LASV. Ad5-GPCLASV elicited both humoral and cellular immune responses in BALB/c mice. Moreover, a bioluminescent imaging-based BALB/c mouse model infected with GPC-bearing and luciferase-expressing replication-incompetent LASV pseudovirus was utilized to evaluate the vaccine efficacy. The bioluminescence intensity of immunized mice was significantly lower than that of control mice after being inoculated with LASV pseudovirus. This study suggests that Ad5-GPCLASV represents a potential vaccine candidate against LF.

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ASFV bearing an I226R gene-deletion elicits a robust immunity in pigs to African swine fever

Journal of Virology ◽

10.1128/jvi.01199-21 ◽

2021 ◽

Author(s):

Yanyan Zhang ◽

Junnan Ke ◽

Jingyuan Zhang ◽

Jinjin Yang ◽

Huixian Yue ◽

...

Keyword(s):

Vaccine Candidate ◽

Clinical Symptoms ◽

African Swine Fever Virus ◽

Clinical Signs ◽

African Swine Fever ◽

Parental Virus ◽

Economic Losses ◽

Egfp Expression ◽

Post Inoculation ◽

Swine Industry

African swine fever (ASF) is a severe hemorrhagic infectious disease in pigs caused by the African swine fever virus (ASFV), leading to devastating economic losses in the epidemic regions. Its control currently depends on thorough culling and clearance of the diseased and the surrounding suspected pigs. ASF vaccine has been extensively explored for years worldwide, especially in hog-intensive areas where it is highly desired, but it is still unavailable due to numerous reasons. Herein, we reported another ASF vaccine candidate named SY18ΔI226R bearing a deletion of the I226R gene in replacement of an eGFP expression cassette at the right end of the viral genome. This deletion results in complete loss of virulence of SY18 as the gene-deleted strain does not cause any clinical symptoms in all pigs inoculated with either a dosage of 10 4.0 TCID 50 or 10 7.0 TCID 50 . An apparent viremia with the gradual decline was monitored, while the virus shedding was only occasionally detected in oral- or anal swabs. ASFV specific antibody appeared at 9 days post-inoculation. After intramuscular challenge with its parental strain ASFV SY18 on 21 days post inoculation, all the challenged pigs survived without obvious febrile or abnormal clinical signs. No viral DNA could be detected on the dissection of any tissue when viremia disappeared. These indicated that SY18ΔI226R is safe in swine and elicits a robust immunity to the virulent ASFV infection. IMPORTANCE: Outbreaks of African swine fever have resulted in devastating losses to the swine industry worldwide, but there is currently no commercial vaccine available. Although several vaccine candidates have been reported, none has been approved for use due to several reasons, especially the ones concerning bio-safety. Here, we identified a new undescribed functional gene, I226R. When deleted from the ASFV genome, the virus completely loses its virulence in the swine. Importantly, pigs infected with this gene-deleted virus were resistant to infection by an intramuscular challenge of 10 2.5 or 10 4.0 TCID 50 of its virulent parental virus. Furthermore, rarely the nucleic acid of the gene-deleted virus and its virulent parental virus was detected from oral- or anal swabs. Viruses could not be detected in any tissues after necropsy when viremia became negative, indicating that robust immunity was achieved. Therefore, SY18ΔI226R is a novel, ideal and efficacious vaccine candidate for genotype II ASF.

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Identification of E2 strain with improved secretion and immunogenicity against CSFV in piglets

10.21203/rs.2.18234/v1 ◽

2019 ◽

Author(s):

Huiling Xu ◽

Yanli Wang ◽

Guangwei Han ◽

Weihuan Fang ◽

fang he

Keyword(s):

Signal Peptide ◽

Protective Immunity ◽

Vaccine Candidate ◽

Classical Swine Fever ◽

Cost Effective ◽

Economic Losses ◽

Swine Industry ◽

Subunit Vaccines ◽

Virus Challenge ◽

Efficacious Vaccine

Abstract Background: Outbreaks of CSFV cause significant economic losses in the swine industry. Subunit vaccines present advantages in DIVA immunogenicity and safety. The technology was limited due to the low yield and the high cost with multiple and large doses. Results: A novel E2 sequence (E2ZJ) was identified from an epidemic strain of Zhejiang for outstanding secretion in baculovirus and enhanced immunogenicity. E2 secretion induced with the selected signal peptide, SPZJ, increase at least 50% as compared to any other signal peptides tested. Besides, unique antigenic features were identified in E2ZJ. E2ZJ elicited CSFV antibody at the earlier stage than other E2 types tested in mice. Meantime, higher level of neutralization antibody with E2ZJ was detected than other E2s at the same dosage. Further, in piglets, E2ZJ successfully elicited neutralizing immunity. A single dose of 5 μg of E2ZJ was sufficient to induce protective antibody against CSFV in piglets and provided 100% protection against lethal virus challenge. Conclusions: In this study, with advantages in secretion and immunogenicity over counterparts, SPZJ-E2ZJ is a cost-effective and efficacious vaccine candidate against CSFV. Keywords: Classical swine fever virus; novel signal peptide; SPZJ-E2ZJ; subunit vaccine; protective immunity

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Survival of classic swine fever virus in hams made from the meat of pigs vaccinated with the PAV-250 strain and unvaccinated pigs

Revista Mexicana de Ciencias Pecuarias ◽

10.22319/rmcp.v10i3.4528 ◽

2019 ◽

Vol 10 (3) ◽

pp. 536-551

Author(s):

Heidi Amezcua Hempel ◽

María Salud Rubio Lozano ◽

Eliseo Manuel Hernández Baumgarten ◽

Pablo Correa Girón † ◽

Oscar Torres Ángeles ◽

...

Keyword(s):

Reference Strain ◽

Clinical Signs ◽

Classical Swine Fever ◽

Fever Virus ◽

Direct Immunofluorescence ◽

Biometric Analysis ◽

Treatment Groups ◽

Group A ◽

Group B ◽

Group D

The study was to determine the presence of Classical Swine Fever virus (CSFv), in the meat of vaccinated pigs with the PAV-250 strain and then challenged using the same strain. Five treatment groups were established (each with four pigs). Group A: Pigs thatwere fed with processed hams from negative animals; Group B: Pigs that were fed with processed hams from commercial pigs inoculated with the ALD (reference strain) (titre of 104.0/ml); Group C: Pigs fed with processed hams from pigs infected with the virulent ALD strain (titre of 102.5/ml); Group D: Pigs fed with processed hams from pigs vaccinated with the PAV-250 strain and challenged with the ALD strain (titre of 101.1/ml); and Group E: Pigs fed with processed hams from pigs vaccinated with two doses of the PAV-250 strain and challenged with the ALD strain (negative). Blood samples were taken at d 1, 5, 10, 15 and 20 for biometric analysis. Groups B, C and D manifested clinical signs of CSFv: 40 °C temperature, anorexia, paralysis, vomiting, diarrhea, tremor, hirsute hair and cyanosis. Pigs were slaughtered and necropsies performed to identify lesions in tissues. Results of direct immunofluorescence testing of tissues were positive and the virus was recovered. Under these study conditions, it was found that CSFv resisted the cooking method at 68 °C for 40 min in hams from unvaccinated pigs, and that the virus was able to transmit the disease to healthy unvaccinated pigs, whereas the hams from the vaccinated animals did not transmit the virus.

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Heritability of the Effect of Corticosteroids on Intraocular Pressure

Acta geneticae medicae et gemellologiae ◽

10.1017/s1120962300025658 ◽

1970 ◽

Vol 19 (1-2) ◽

pp. 264-267 ◽

Cited By ~ 4

Author(s):

F.H. Reuling ◽

J.T. Schwartz

Keyword(s):

Intraocular Pressure ◽

Clinical Signs ◽

Topical Steroids ◽

Frequency Distributions ◽

Steroid Response ◽

Large Numbers ◽

Wide Range ◽

Allele Pair ◽

High Level ◽

Genetically Determined

In the late 1950's and early 1960's, it became evident that some glaucoma patients developed elevations of intraocular pressure, which were difficult to control, following prolonged use of systemic or ocular medications containing corticosteroids (Chandler, 1955, Alfano, 1963; Armaly, 1963). In addition, some patients without glaucoma, when treated with steroids for long periods of time, developed clinical signs of chronic simple glaucoma (McLean, 1950; François, 1954; Covell, 1958; Linner, 1959; Goldman, 1962). Fortunately, the elevation of intraocular pressure was reversible if the drug was discontinued.Over the past decade, extensive investigation of the “steroid response” has been undertaken. For this presentation, the steroid response may be considered as a gradual elevation of intraocular pressure, occurring over several weeks, in an eye being medicated with corticosteroid drops several times a day. The elevation in pressure is usually accompanied by a reduction in the facility of aqueous outflow. When relatively large numbers of subjects were tested with topical steroids, so that a wide range of responsiveness could be observed, a variation in individual sensitivity was demonstrated. Frequency distributions of intraocular pressure or change in pressure following steroids showed a skew toward the high side. On the basis of trimodal characteristics which they observed in such frequency distributions, Becker and Hahn (1964), Becker (1965) and Armaly (1965, 1966) considered the possible existence of several genetically determined subpopulations. These investigators distinguished three subpopulations on the basis of low, intermediate, and high levels of pressure response. It was hypothesized that these levels of response characterized three phenotypes, corresponding to the three possible genotypes of an allele pair, wherein one member of the pair determined a low level of response, and the other member determined a high level of response (Armaly, 1967).

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Porcine Gammaherpesviruses in Italian Commercial Swine Population: Frequent but Harmless

Pathogens ◽

10.3390/pathogens10010047 ◽

2021 ◽

Vol 10 (1) ◽

pp. 47

Author(s):

Giovanni Franzo ◽

Michele Drigo ◽

Matteo Legnardi ◽

Laura Grassi ◽

Maria Luisa Menandro ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Clinical Signs ◽

Northern Italy ◽

Porcine Circovirus ◽

Swine Industry ◽

Positive Interaction ◽

High Prevalence ◽

Swine Population ◽

Clinical Conditions

Differently from alpha- and betaherpesviruses affecting swine, interest in the recently discovered Suid gammaherpesvirus 3, Suid gammaherpesvirus 4, and Suid gammaherpesvirus 5, also known as porcine lymphotropic herpesviruses (PLHV-1, PLHV-2, and PLHV-3), has largely focused on their role as potential zoonotic agents in cases of xenotransplantation. However, their role as primary pathogens of swine or as co-factors for other lymphotropic infections has essentially been neglected. The present study aims at filling this gap, evaluating the association between PLHVs infection and different clinical conditions and/or porcine circovirus (PCV) co-infection. One hundred seventy-six samples were obtained from different animals located in a high-density pig area of Northern Italy in the period 2017–2020. The presence of PLHVs and PCVs was tested and quantified by specific real-time PCR: PLHVs were widespread among pigs (PLHV-1, PLHV-2, and PLHV-3 prevalence was 28.97%, 10.79%, and 4.54%, respectively) and detected in all considered tissues and clinical conditions. Frequent co-infections were also observed among PLHVs and with PCVs, although a significant association was not detected with the exception of a positive interaction between PLHV-1 and PLHV-3, and a negative one between PLHV-2 and PCV-2. Significantly, no association between PLHVs, alone or in co-infection, emerged with any of the considered clinical signs, their frequency being comparable between healthy and diseased animals. Based on these pieces of evidence and despite their high prevalence, PLHVs’ relevance for the swine industry appears negligible, either as primary pathogens or as predisposing factors for circovirus-induced diseases.

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Protection against the New Equine Influenza Virus Florida Clade I Outbreak Strain Provided by a Whole Inactivated Virus Vaccine

Vaccines ◽

10.3390/vaccines8040784 ◽

2020 ◽

Vol 8 (4) ◽

pp. 784

Author(s):

Sylvia Reemers ◽

Sander van Bommel ◽

Qi Cao ◽

David Sutton ◽

Saskia van de Zande

Keyword(s):

Influenza Virus ◽

Virus Vaccine ◽

Clinical Signs ◽

Field Strain ◽

Equine Influenza Virus ◽

Outbreak Strain ◽

Virus Shedding ◽

Equine Influenza ◽

Vaccine Type ◽

High Level

Equine influenza virus (EIV) is a major cause of respiratory disease in horses. Vaccination is an effective tool for infection control. Although various EIV vaccines are widely available, major outbreaks occurred in Europe in 2018 involving a new EIV H3N8 FC1 strain. In France, it was reported that both unvaccinated and vaccinated horses were affected despite >80% vaccination coverage and most horses being vaccinated with a vaccine expressing FC1 antigen. This study assessed whether vaccine type, next to antigenic difference between vaccine and field strain, plays a role. Horses were vaccinated with an ISCOMatrix-adjuvanted, whole inactivated virus vaccine (Equilis Prequenza) and experimentally infected with the new FC1 outbreak strain. Serology (HI), clinical signs, and virus shedding were evaluated in vaccinated compared to unvaccinated horses. Results showed a significant reduction in clinical signs and a lack of virus shedding in vaccinated horses compared to unvaccinated controls. From these results, it can be concluded that Equilis Prequenza provides a high level of protection to challenge with the new FC1 outbreak strain. This suggests that, apart from antigenic differences between vaccine and field strain, other aspects of the vaccine may also play an important role in determining field efficacy.

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Experimental infection of indigenous North African goats with goatpox virus

Acta Veterinaria Scandinavica ◽

10.1186/s13028-021-00574-2 ◽

2021 ◽

Vol 63 (1) ◽

Author(s):

Jihane Hamdi ◽

Zahra Bamouh ◽

Mohammed Jazouli ◽

Meryem Alhyane ◽

Najet Safini ◽

...

Keyword(s):

Antibody Response ◽

Experimental Infection ◽

Subcutaneous Tissue ◽

Severe Disease ◽

Clinical Signs ◽

Economic Losses ◽

North African ◽

Cutaneous Lesions ◽

Viral Dna ◽

Goatpox Virus

Abstract Background Goatpox is a viral disease caused by infection with goatpox virus (GTPV) of the genus Capripoxvirus, Poxviridae family. Capripoxviruses cause serious disease to livestock and contribute to huge economic losses. Goatpox and sheeppox are endemic to Africa, particularly north of the Equator, the Middle East and many parts of Asia. GTPV and sheeppox virus are considered host-specific; however, both strains can cause clinical disease in either goats or sheep with more severe disease in the homologous species and mild or sub-clinical infection in the other. Goatpox has never been reported in Morocco, Algeria or Tunisia despite the huge population of goats living in proximity with sheep in those countries. To evaluate the susceptibility and pathogenicity of indigenous North African goats to GTPV infection, we experimentally inoculated eight locally bred goats with a virulent Vietnamese isolate of GTPV. Two uninfected goats were kept as controls. Clinical examination was carried out daily and blood was sampled for virology and for investigating the antibody response. After necropsy, tissues were collected and assessed for viral DNA using real-time PCR. Results Following the experimental infection, all inoculated goats displayed clinical signs characteristic of goatpox including varying degrees of hyperthermia, loss of appetite, inactivity and cutaneous lesions. The infection severely affected three of the infected animals while moderate to mild disease was noticed in the remaining goats. A high antibody response was developed. High viral DNA loads were detected in skin crusts and nodules, and subcutaneous tissue at the injection site with cycle threshold (Ct) values ranging from 14.6 to 22.9, while lower viral loads were found in liver and lung (Ct = 35.7 and 35.1). The results confirmed subcutaneous tropism of the virus. Conclusion Clinical signs of goatpox were reproduced in indigenous North African goats and confirmed a high susceptibility of the North African goat breed to GTPV infection. A clinical scoring system is proposed that can be applied in GTPV vaccine efficacy studies.

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