Evaluation of the Cross-Protective Efficacy of a Chimeric PRRSV Vaccine against Two Genetically Diverse PRRSV2 Field Strains in a Reproductive Model

Despite the routine use of porcine reproductive and respiratory syndrome (PRRS)-modified live vaccines, serious concerns are currently being raised due to their quick reversion to virulence and limited cross-protection against divergent PRRS virus (PRRSV) strains circulating in the field. Therefore, a PRRS chimeric vaccine (JB1) was produced using a DNA-launched infectious clone by replacing open reading frames (ORFs) 3–6 with those from a mixture of two genetically different PRRSV2 strains (K07–2273 and K08–1054) and ORF1a with that from a mutation-resistant PRRSV strain (RVRp22) exhibiting an attenuated phenotype. To evaluate the safety and cross-protective efficacy of JB1 in a reproductive model, eight PRRS-negative pregnant sows were purchased and divided into four groups. Four sows in two of the groups were vaccinated with JB1, and the other 4 sows were untreated at gestational day 60. At gestational day 93, one vaccinated group and one nonvaccinated group each were challenged with either K07–2273 or K08–1054. All of the sows aborted or delivered until gestation day 115 (24 days post challenge), and the newborn piglets were observed up to the 28th day after birth, which was the end of the experiment. Overall, pregnant sows of the JB1-vaccinated groups showed no meaningful viremia after vaccination and significant reductions in viremia with K07–2273 and K08–1054, exhibiting significantly higher levels of serum virus-neutralizing antibodies than non-vaccinated sows. Moreover, the JB1-vaccinated groups did not exhibit any abortion due to vaccination and showed improved piglet viability and birth weight. The piglets from JB1-vaccinated sows displayed lower viral concentrations in serum and fewer lung lesions compared with those of the piglets from the nonvaccinated sows. Therefore, JB1 is a safe and effective vaccine candidate that confers simultaneous protection against two genetically different PRRSV strains.

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Development of a Sensitive Detection Method for Alphaviruses and Its Use as a Virus Neutralization Assay

Viruses ◽

10.3390/v13071191 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1191

Author(s):

Christin Schmidt ◽

Mario Perkovic ◽

Barbara S. Schnierle

Keyword(s):

Neutralizing Antibodies ◽

High Sensitivity ◽

Neutralization Assay ◽

Open Reading Frames ◽

Virus Neutralization ◽

Structural Genes ◽

Virus Neutralization Assay ◽

Subgenomic Promoter ◽

Mayaro Virus ◽

Reading Frames

Alphaviruses have a single-stranded, positive-sense RNA genome that contains two open reading frames encoding either the non-structural or the structural genes. Upon infection, the genomic RNA is translated into the non-structural proteins (nsPs). NsPs are required for viral RNA replication and transcription driven from the subgenomic promoter (sgP). Transfection of an RNA encoding the luciferase gene under the control of the sgP into cells enabled the detection of replication-competent chikungunya virus (CHIKV) or Mayaro virus (MAYV) with high sensitivity as a function of the induced luciferase activity. This assay principle was additionally used to analyze virus-neutralizing antibodies in sera and might be an alternative to standard virus neutralization assays based on virus titration or the use of genetically modified tagged viruses.

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Immunogenicity and protective efficacy of BBV152: a whole virion inactivated SARS CoV-2 vaccine in the Syrian hamster model

10.21203/rs.3.rs-76768/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Sreelekshmy Mohandas ◽

Pragya D Yadav ◽

Anita Shete ◽

Priya Abraham ◽

Krishna Mohan ◽

...

Keyword(s):

Immune Response ◽

Respiratory Tract ◽

Neutralizing Antibodies ◽

Protective Efficacy ◽

Effective Vaccine ◽

Lung Pathology ◽

Upper Respiratory Tract ◽

Hamster Model ◽

Humoral Immune ◽

Robust Immune Response

Abstract The availability of a safe and effective vaccine would be the eventual measure to deal with SARS-CoV-2 threat. Here, we have developed and assessed the immunogenicity and protective efficacy of an inactivated SARS-CoV-2 vaccine (BBV152) in hamsters. Three dose vaccination regime with three formulations of BBV152 induced significant titres of SARS-CoV-2 specific IgG and neutralizing antibodies. The formulation with imidazoquinoline adsorbed on alum adjuvant remarkably generated a quick and robust immune response. Th1 biased immune response was demonstrated by the detection of IgG2 antibodies. Post-SARS-CoV-2 infection, vaccinated hamsters did not show any histopathological changes in the lungs. The protection of the hamsters was evident by the rapid clearance of the virus from lower respiratory tract, reduced virus load in upper respiratory tract, absence of lung pathology and robust humoral immune response. These findings confirm the immunogenic potential of BBV152 and further protection of hamsters challenged with SARS-CoV-2.

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Antibodies Elicited by Multiple Envelope Glycoprotein Immunogens in Primates Neutralize Primary Human Immunodeficiency Viruses (HIV-1) Sensitized by CD4-Mimetic Compounds

Journal of Virology ◽

10.1128/jvi.03211-15 ◽

2016 ◽

Vol 90 (10) ◽

pp. 5031-5046 ◽

Cited By ~ 21

Author(s):

Navid Madani ◽

Amy M. Princiotto ◽

David Easterhoff ◽

Todd Bradley ◽

Kan Luo ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Small Molecule ◽

Conformational Changes ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Protective Efficacy ◽

Effective Vaccine ◽

Broadly Neutralizing Antibodies ◽

Variable Regions ◽

Hiv 1

ABSTRACTThe human immunodeficiency virus (HIV-1) envelope glycoproteins (Env) mediate virus entry through a series of complex conformational changes triggered by binding to the receptors CD4 and CCR5/CXCR4. Broadly neutralizing antibodies that recognize conserved Env epitopes are thought to be an important component of a protective immune response. However, to date, HIV-1 Env immunogens that elicit broadly neutralizing antibodies have not been identified, creating hurdles for vaccine development. Small-molecule CD4-mimetic compounds engage the CD4-binding pocket on the gp120 exterior Env and induce Env conformations that are highly sensitive to neutralization by antibodies, including antibodies directed against the conserved Env region that interacts with CCR5/CXCR4. Here, we show that CD4-mimetic compounds sensitize primary HIV-1 to neutralization by antibodies that can be elicited in monkeys and humans within 6 months by several Env vaccine candidates, including gp120 monomers. Monoclonal antibodies directed against the gp120 V2 and V3 variable regions were isolated from the immunized monkeys and humans; these monoclonal antibodies neutralized a primary HIV-1 only when the virus was sensitized by a CD4-mimetic compound. Thus, in addition to their direct antiviral effect, CD4-mimetic compounds dramatically enhance the HIV-1-neutralizing activity of antibodies that can be elicited with currently available immunogens. Used as components of microbicides, the CD4-mimetic compounds might increase the protective efficacy of HIV-1 vaccines.IMPORTANCEPreventing HIV-1 transmission is a high priority for global health. Eliciting antibodies that can neutralize transmitted strains of HIV-1 is difficult, creating problems for the development of an effective vaccine. We found that small-molecule CD4-mimetic compounds sensitize HIV-1 to antibodies that can be elicited in vaccinated humans and monkeys. These results suggest an approach to prevent HIV-1 sexual transmission in which a virus-sensitizing microbicide is combined with a vaccine.

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Recombinant Chimeric Yellow Fever-Dengue Type 2 Virus Is Immunogenic and Protective in Nonhuman Primates

Journal of Virology ◽

10.1128/jvi.74.12.5477-5485.2000 ◽

2000 ◽

Vol 74 (12) ◽

pp. 5477-5485 ◽

Cited By ~ 160

Author(s):

F. Guirakhoo ◽

R. Weltzin ◽

T. J. Chambers ◽

Z.-X. Zhang ◽

K. Soike ◽

...

Keyword(s):

Yellow Fever ◽

Neutralizing Antibodies ◽

Protective Efficacy ◽

Infectious Clone ◽

Vero Cells ◽

Control Group ◽

Placebo Control ◽

Wild Type

ABSTRACT A chimeric yellow fever (YF)-dengue type 2 (dengue-2) virus (ChimeriVax-D2) was constructed using a recombinant cDNA infectious clone of a YF vaccine strain (YF 17D) as a backbone into which we inserted the premembrane (prM) and envelope (E) genes of dengue-2 virus (strain PUO-218 from a case of dengue fever in Bangkok, Thailand). The chimeric virus was recovered from the supernatant of Vero cells transfected with RNA transcripts and amplified once in these cells to yield a titer of 6.3 log10 PFU/ml. The ChimeriVax-D2 was not neurovirulent for 4-week-old outbred mice inoculated intracerebrally. This virus was evaluated in rhesus monkeys for its safety (induction of viremia) and protective efficacy (induction of anti-dengue-2 neutralizing antibodies and protection against challenge). In one experiment, groups of non-YF-immune monkeys received graded doses of ChimeriVax-D2; a control group received only the vaccine diluents. All monkeys (except the control group) developed a brief viremia and showed no signs of illness. Sixty-two days postimmunization, animals were challenged with 5.0 log10focus forming units (FFU) of a wild-type dengue-2 virus. No viremia (<1.7 log10 FFU/ml) was detected in any vaccinated group, whereas all animals in the placebo control group developed viremia. All vaccinated monkeys developed neutralizing antibodies in a dose-dependent response. In another experiment, viremia and production of neutralizing antibodies were determined in YF-immune monkeys that received either ChimeriVax-D2 or a wild-type dengue-2 virus. Low viremia was detected in ChimeriVax-D2-inoculated monkeys, whereas all dengue-2-immunized animals became viremic. All of these animals were protected against challenge with a wild-type dengue-2 virus, whereas all YF-immune monkeys and nonimmune controls became viremic upon challenge. Genetic stability of ChimeriVax-D2 was assessed by continuous in vitro passage in VeroPM cells. The titer of ChimeriVax-D2, the attenuated phenotype for 4-week-old mice, and the sequence of the inserted prME genes were unchanged after 18 passages in Vero cells. The high replication efficiency, attenuation phenotype in mice and monkeys, immunogenicity and protective efficacy, and genomic stability of ChimeriVax-D2 justify it as a novel vaccine candidate to be evaluated in humans.

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Heterologous prime-boost immunizations with chimpanzee adenoviral vectors elicit potent and protective immunity against SARS-CoV-2 infection

Cell Discovery ◽

10.1038/s41421-021-00360-4 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jiaojiao Liu ◽

Kun Xu ◽

Man Xing ◽

Yue Zhuo ◽

Jingao Guo ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Immune Cell ◽

Protective Efficacy ◽

Effective Vaccine ◽

Vaccine Candidates ◽

Cell Responses ◽

Global Pandemic ◽

Specific Memory ◽

Boost Immunization ◽

Protective Antibodies

AbstractA safe and effective vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is urgently needed to tackle the COVID-19 global pandemic. Here, we describe the development of chimpanzee adenovirus serotypes 6 and 68 (AdC6 and AdC68) vector-based vaccine candidates expressing the full-length transmembrane spike glycoprotein. We assessed the vaccine immunogenicity, protective efficacy, and immune cell profiles using single-cell RNA sequencing in mice. Mice were vaccinated via the intramuscular route with the two vaccine candidates using prime-only regimens or heterologous prime-boost regimens. Both chimpanzee adenovirus-based vaccines elicited strong and long-term antibody and T cell responses, balanced Th1/Th2 cell responses, robust germinal center responses, and provided effective protection against SARS-CoV-2 infection in mouse lungs. Strikingly, we found that heterologous prime-boost immunization induced higher titers of protective antibodies, and more spike-specific memory CD8+ T cells in mice. Potent neutralizing antibodies produced against the highly transmissible SARS-CoV-2 variants B.1.1.7 lineage (also known as N501Y.V1) and B.1.351 lineage (also known as N501Y.V2) were detectable in mouse sera over 6 months after prime immunization. Our results demonstrate that the heterologous prime-boost strategy with chimpanzee adenovirus-based vaccines is promising for further development to prevent SARS-CoV-2 infection.

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Spinach curly top virus: A Newly Described Curtovirus Species from Southwest Texas with Incongruent Gene Phylogenies

Phytopathology ◽

10.1094/phyto.2004.94.7.772 ◽

2004 ◽

Vol 94 (7) ◽

pp. 772-779 ◽

Cited By ~ 38

Author(s):

Surendranath Baliji ◽

Mark C. Black ◽

Roy French ◽

Drake C. Stenger ◽

Garry Sunter

Keyword(s):

Tandem Repeats ◽

Infectious Clone ◽

Blot Hybridization ◽

Systemic Infection ◽

Southern Blot Hybridization ◽

Complete Sequence ◽

Open Reading Frames ◽

Viral Dna ◽

Severe Stunting ◽

Reading Frames

A curtovirus associated with a disease of spinach was isolated in southwest Texas during 1996. Disease symptoms included severe stunting and chlorosis, with younger leaves curled, distorted, and dwarfed. Viral DNA was purified and an infectious clone obtained. Agroinoculation using a construct bearing full-length tandem repeats of the cloned viral genome resulted in systemic infection of species in six of seven plant families tested, indicating that the virus has a wide host range. Symptoms produced in spinach agroinoculated with cloned viral DNA were similar to those observed in the field. Viral single-stranded and double-stranded DNA forms typical of curtovirus infection were detected in host plants by Southern blot hybridization. The complete sequence of the infectious clone comprised 2,925 nucleotides, with seven open reading frames encoding proteins homologous to those of other curtoviruses. Complete genome comparisons revealed that the spinach curtovirus shared 64.2 to 83.9% nucleotide sequence identity relative to four previously characterized curtovirus species: Beet curly top virus, Beet severe curly top virus, Beet mild curly top virus, and Horseradish curly top virus. Phylogenetic analysis of individual open reading frames indicated that the evolutionary history of the three virion-sense genes was different from that of the four complementary-sense genes, suggesting that recombination among curtoviruses may have occurred. Collectively, these results indicate that the spinach curtovirus characterized here represents a newly described species of the genus Curtovirus, for which we propose the name Spinach curly top virus.

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Cloning and sequence analysis of an infectious clone of Citrus yellow mosaic virus that can infect sweet orange via Agrobacterium-mediated inoculation

Journal of General Virology ◽

10.1099/0022-1317-82-10-2549 ◽

2001 ◽

Vol 82 (10) ◽

pp. 2549-2558 ◽

Cited By ~ 41

Author(s):

Qi Huang ◽

John S. Hartung

Keyword(s):

Mosaic Virus ◽

Sweet Orange ◽

Infectious Clone ◽

Mosaic Disease ◽

Open Reading Frames ◽

Yellow Mosaic Virus ◽

Virus Movement ◽

The Family ◽

Cacao Swollen Shoot Virus ◽

Reading Frames

Citrus yellow mosaic virus (CYMV), a member of the family Caulimoviridae, genus Badnavirus, causes citrus mosaic disease, a disease that occurs commonly in India. The CYMV genome has been cloned and its complete nucleotide sequence determined. Its DNA genome is 7559 bp in length and contains six putative open reading frames (ORFs), all on the plus-strand of the genome and each capable of encoding proteins with a molecular mass of greater than 10 kDa. ORF 3, the largest ORF, encodes a putative polyprotein for functions involved in virus movement, assembly and replication. The other ORFs encode proteins whose exact functions are not completely understood. The genome also contains a plant tRNAmet-binding site, which may serve as a primer for minus-strand DNA synthesis, in its intergenic region. Phylogenetic analysis of the badnaviruses revealed that CYMV is most closely related to Cacao swollen shoot virus. It was demonstrated that a construct containing 1·4 copies of the cloned CYMV genome could infect sweet orange via Agrobacterium-mediated inoculation.

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Characterization of Two Immunodominant Antigenic Peptides in NSP2 of PRRSV-2 and Generation of a Marker PRRSV Strain Based on the Peptides

10.21203/rs.3.rs-961613/v1 ◽

2021 ◽

Author(s):

Dong-Yan Li ◽

Xing-Yang Cui ◽

Xin-Yi Huang ◽

Yue Hu ◽

Xiao-Xiao Tian ◽

...

Keyword(s):

Infectious Clone ◽

Economic Importance ◽

Deletion Mutants ◽

Antigenic Peptides ◽

Structural Protein ◽

Prrs Virus ◽

Great Economic Importance ◽

Animal Remains ◽

Prrsv Strain

Abstract Porcine reproductive and respiratory syndrome (PRRS) is a widespread disease with great economic importance in the pig industry. Although vaccines against the PRRS virus (PRRSV) have been employed for more than 20 years, differentiating infected from vaccinated animal remains challenging. In this study, all 907 non-structural protein 2 (NSP2) full-length sequences of PRRSV-2 available from GenBank were aligned. Two peptides, at positions 562–627 (m1B) and 749–813 (m2B) of NSP2, were selected, and their potential for use in differential diagnosis was assessed. Both m1B and m2B were recognized by PRRSV-positive pig serum in peptide-coated enzyme-linked immunosorbent assays. Further epitope identification yielded five overlapping short peptides for the immunodominant regions of m1B and m2B. Using the infectious clone of PRRSV HuN4-F112 as a template, the deletion mutants rHuN4-F112-m1B, rHuN4-F112-m2B, and rHuN4-F112-C5-m1B-m2B were generated and successfully rescued in Marc-145 cells. Growth kinetics revealed that deletion of m1B and m2B did not significantly affect virus replication. Hence, m1B and m2B show potential as molecular markers for developing a PRRSV vaccine.

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