scholarly journals Characterisation of SARS-CoV-2 Lentiviral Pseudotypes and Correlation between Pseudotype-Based Neutralisation Assays and Live Virus-Based Micro Neutralisation Assays

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1011 ◽  
Author(s):  
Inesa Hyseni ◽  
Eleonora Molesti ◽  
Linda Benincasa ◽  
Pietro Piu ◽  
Elisa Casa ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Spike Protein ◽  
Wild Type Virus ◽  
Wild Type ◽  
Serum Samples ◽  
Live Virus ◽  
Rapid Spread ◽  
Recent Outbreak ◽  
Human Sera ◽  
Novel Coronavirus

The recent outbreak of a novel Coronavirus (SARS-CoV-2) and its rapid spread across the continents has generated an urgent need for assays to detect the neutralising activity of human sera or human monoclonal antibodies against SARS-CoV-2 spike protein and to evaluate the serological immunity in humans. Since the accessibility of live virus microneutralisation (MN) assays with SARS-CoV-2 is limited and requires enhanced bio-containment, the approach based on “pseudotyping” can be considered a useful complement to other serological assays. After fully characterising lentiviral pseudotypes bearing the SARS-CoV-2 spike protein, we employed them in pseudotype-based neutralisation assays in order to profile the neutralising activity of human serum samples from an Italian sero-epidemiological study. The results obtained with pseudotype-based neutralisation assays mirrored those obtained when the same panel of sera was tested against the wild type virus, showing an evident convergence of the pseudotype-based neutralisation and MN results. The overall results lead to the conclusion that the pseudotype-based neutralisation assay is a valid alternative to using the wild-type strain, and although this system needs to be optimised and standardised, it can not only complement the classical serological methods, but also allows serological assessments to be made when other methods cannot be employed, especially in a human pandemic context.

scholarly journals A Spike protein-based subunit SARS-CoV-2 vaccine for pets: safety, immunogenicity, and protective efficacy in juvenile cats

2021 ◽  
Author(s):  
Kairat Tabynov ◽  
Madiana Orynbassar ◽  
Leila Yelchibayeva ◽  
Nurkeldi Turebekov ◽  
Toktassyn Yerubayev ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Neutralizing Antibodies ◽  
Large Scale ◽  
Protective Efficacy ◽  
Spike Protein ◽  
Wild Type Virus ◽  
Upper Respiratory Tract ◽  
Wild Type ◽  
Serum Samples ◽  
Virus Shedding

Abstract Whereas multiple vaccine types have been developed to curb the spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) among humans, there are very few vaccines being developed for animals including pets. To combat the threat of human-to-animal, animal-to-animal and animal-to-human transmission and the generation of new virus variants, we developed a subunit SARS-CoV-2 vaccine which is based on recombinant spike protein extracellular domain expressed in insect cells then formulated with appropriate adjuvants. Sixteen 8-12-week-old outbred female and male kittens (n=4/group) were randomly assigned into four treatment groups: Group 1, Antigen alone; Group 2, Sepivac SWE™ adjuvant; Group 3, aluminum hydroxide adjuvant; Group 4, PBS administered control animals. All animals were vaccinated twice at day 0 and 14, intramuscularly in a volume of 0.5 mL (Groups 1-3: 5 µg of Spike protein). On days 0 and 28 serum samples were collected to evaluate anti-spike IgG, inhibition of spike binding to angiotensin-converting enzyme 2 (ACE-2), neutralizing antibodies to Wuhan-01 SARS-CoV-2 D614G (wild-type) and Delta variant viruses, and whole blood for hematology studies. At day 28, all groups were challenged with SARS-CoV-2 wild-type virus 106 TCID50 intranasally. On day 31, tissue samples (lung, heart, and nasal turbinates) were collected for histology, viral RNA detection and virus titration. Parameters evaluated in this study included safety, immunogenicity, and protection from infection with wild-type SARS-CoV-2 virus. After two immunizations, both vaccines induced high titers of serum anti-spike IgG, ACE-2 binding inhibitory and neutralizing antibodies against both wild-type and Delta variant virus in the juvenile cats. Both subunit vaccines provided protection of juvenile cats against virus shedding from the upper respiratory tract, and against viral replication in the lower respiratory tract and hearts. These promising data warrant ongoing evaluation of the vaccine’s ability to protect cats against SARS-CoV-2 Delta variant and in particular to prevent transmission of the infection to naïve cats, before proceeding with large-scale field trials.

scholarly journals Systemic Polyomavirus Genome Increase and Dissemination of Capsid-Defective Genomes in Mammary Gland Tumor-Bearing Mice

2000 ◽  
Vol 74 (15) ◽  
pp. 6975-6983 ◽  
Author(s):  
Julie J. Wirth ◽  
Li Chen ◽  
Michele M. Fluck
Keyword(s):  
Mammary Gland ◽  
Viral Genome ◽  
Wild Type Strain ◽  
Neonatal Infection ◽  
Wild Type ◽  
Coding Region ◽  
Live Virus ◽  
Viral Genomes ◽  
Mammary Gland Tumors ◽  
Low Levels

ABSTRACT BALB/c mice that developed tumors 7 to 8 months following neonatal infection by polyomavirus (PYV) wild-type strain A2 were characterized with respect to the abundance and integrity of the viral genome in the tumors and in 12 nontumorous organs. These patterns were compared to those found in tumor-free mice infected in parallel. Six mice were analyzed in detail including four sibling females with mammary gland tumors. In four of five mammary gland tumors, the viral genome had undergone a unique deletion and/or rearrangement. Three tumor-resident genomes with an apparently intact large T coding region were present in abundant levels in an unintegrated state. Two of these had undergone deletions and rearrangements involving the capsid genes and therefore lacked the capacity to produce live virus. In the comparative organ survey, the tumors harboring replication-competent genomes contained by far the highest levels of genomes of any tissue. However, the levels of PYV genomes in other organs were elevated by up to 1 to 2 orders of magnitude compared to those detected in the same organs of tumor-free mice. The genomes found in the nontumorous organs had the same rearrangements as the genomes residing in the tumors. The original wild-type genome was detected at low levels in a few organs, particularly in the kidneys. The data indicate that a systemic increase in the level of viral genomes occurred in conjunction with the induction of tumors by PYV. The results suggest two novel hypotheses: (i) that genomes may spread from the tumors to the usual PYV target tissues and (ii) that this dissemination may take place in the absence of capsids, providing an important path for a virus to escape from the immune response. This situation may offer a useful model for the spread of HPV accompanying HPV-induced oncogenesis.

scholarly journals Priming with tat-Deleted Caprine Arthritis Encephalitis Virus (CAEV) Proviral DNA or Live Virus Protects Goats from Challenge with Pathogenic CAEV

1998 ◽  
Vol 72 (8) ◽  
pp. 6796-6804 ◽  
Author(s):  
Abdallah Harmache ◽  
Christian Vitu ◽  
François Guiguen ◽  
Pierre Russo ◽  
Giuseppe Bertoni ◽  
...  
Keyword(s):  
Virus Isolation ◽  
Encephalitis Virus ◽  
Wild Type Virus ◽  
Infection Model ◽  
Wild Type ◽  
Live Virus ◽  
Caprine Arthritis Encephalitis Virus ◽  
Proviral Dna ◽  
Homologous Virus

ABSTRACT We previously reported that infection of goats with caprine arthritis encephalitis virus (CAEV) tat− proviral DNA or virus results in persistent infection, since the animals seroconverted and direct virus isolation from cultures of blood-derived macrophages was positive. In this study we wanted to determine whether goats injected with CAEV tat− proviral DNA or virus were protected against challenge with the pathogenic homologous virus and to investigate whether CAEV tat− was still pathogenic. All animals injected with CAEV tat− became infected as indicated by seroconversion and virus isolation. Challenge at 8 or 9 months postinfection demonstrated protection in four of four animals injected with CAEV tat− but did not in three of three mock-inoculated challenged goats. Challenge virus was undetectable in the blood macrophages of protected animals during a period of 6 or 10 months postchallenge. In two of four protected animals, however, we were able to detect the challenge wild-type virus by reverse transcriptase PCR on RNA directly extracted from synovial membrane cells surrounding the inoculation site. This result suggests that protection was achieved without complete sterilizing immunity. Animals injected with CAEV tat− and mock challenged developed inflammatory lesions in the joints, although these lesions were not as severe as those in CAEV wild-type-injected goats. These results confirm the dispensable role of Tat in CAEV replication in vivo for the establishment of infection and pathogenesis and demonstrate in another lentivirus infection model the efficacy of live attenuated viruses to induce resistance to superinfection.

Poliovirus vaccination: current understanding of poliovirus interactions in humans and implications for the eradication of poliomyelitis

1999 ◽  
Vol 1 (13) ◽  
pp. 1-17 ◽  
Author(s):  
Philip D. Minor
Keyword(s):  
Informed Choice ◽  
Oral Route ◽  
World Health ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Live Virus ◽  
Live Vaccines ◽  
The World ◽  
Strain Virus

Poliomyelitis is a paralytic disease of the motor neurones of the central nervous system, which is caused by poliovirus. The virus is transmitted by the faecal–oral route, and if virus replication is confined to the gut, it is harmless. Poliomyelitis is an ancient human disease, but was rare until the beginning of the 20th century, when children began to be exposed to the virus at older ages and were, therefore, no longer protected by maternal antibody, which had already been lost. Inactivated polio vaccines are increasingly being used in those countries in which poliomyelitis has been brought under control; however, live vaccines are still the most widely used types and the World Health Organization (WHO) have set the goal of using such vaccines to eliminate the wild-type virus throughout the world by the year 2000. Substantial progress has been made to this end; however, the strains of poliovirus that are used as vaccines are able to adapt rapidly to the human gut, losing their attenuated (weakened) character within a few weeks. Currently, there is urgent debate about the best method of stopping vaccination against poliomyelitis once the wild-type poliovirus has been eliminated completely, so that the vaccine-strain virus will also be eliminated. Proposed strategies include the abrupt cessation of vaccination with the live virus worldwide, followed by the optional use of inactivated vaccines for an appropriate period. Further information about both the epidemiology and the pathogenesis of the disease is required before an informed choice can be made. The topics covered in this article include a brief history of studies of the disease, its pathogenesis and its control by vaccination, the molecular biology of the live vaccines, which have been extremely successful in controlling poliomyelitis so far, and the concerns that are raised as the eradication of the wild-type virus approaches.

scholarly journals The UL47 gene of avian infectious laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens

2007 ◽  
Vol 88 (3) ◽  
pp. 732-742 ◽  
Author(s):  
Dorothee Helferich ◽  
Jutta Veits ◽  
Jens P. Teifke ◽  
Thomas C. Mettenleiter ◽  
Walter Fuchs
Keyword(s):  
Deletion Mutant ◽  
Cultured Cells ◽  
Functional Characterization ◽  
Wild Type Virus ◽  
Wild Type ◽  
Infectious Laryngotracheitis Virus ◽  
Live Virus ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus

The genome of infectious laryngotracheitis virus (ILTV) exhibits several differences from those of other avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3′-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.

scholarly journals Ultrapotent bispecific antibodies neutralize emerging SARS-CoV-2 variants

2021 ◽  
Author(s):  
Hyeseon Cho ◽  
Kristina Kay Gonzales-Wartz ◽  
Deli Huang ◽  
Meng Yuan ◽  
Mary Peterson ◽  
...  
Keyword(s):  
Bispecific Antibody ◽  
Complete Loss ◽  
Memory B Cells ◽  
Spike Protein ◽  
Bispecific Antibodies ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Hamster Model

The emergence of SARS-CoV-2 variants that threaten the efficacy of existing vaccines and therapeutic antibodies underscores the urgent need for new antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells of COVID-19 patients. The three most potent antibodies targeted distinct regions of the RBD, and all three neutralized the SARS-CoV-2 variants B.1.1.7 and B.1.351. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the ACE2 receptor, and has limited contact with key variant residues K417, E484 and N501. We designed bispecific antibodies by combining non-overlapping specificities and identified five ultrapotent bispecific antibodies that inhibit authentic SARS-CoV-2 infection at concentrations of <1 ng/mL. Through a novel mode of action three bispecific antibodies cross-linked adjacent spike proteins using dual NTD/RBD specificities. One bispecific antibody was >100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a 2.5 mg/kg dose. Notably, six of nine bispecific antibodies neutralized B.1.1.7, B.1.351 and the wild-type virus with comparable potency, despite partial or complete loss of activity of at least one parent monoclonal antibody against B.1.351. Furthermore, a bispecific antibody that neutralized B.1.351 protected against SARS-CoV-2 expressing the crucial E484K mutation in the hamster model. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.

scholarly journals Age-Dependent Reduction in Neutralization against Alpha and Beta Variants of BNT162b2 SARS-CoV-2 Vaccine-Induced Immunity

2021 ◽  
Author(s):  
Hitoshi Kawasuji ◽  
Yoshitomo Morinaga ◽  
Hideki Tani ◽  
Yumiko Saga ◽  
Makito Kaneda ◽  
...  
Keyword(s):  
Age Groups ◽  
Older Age ◽  
Spike Protein ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Neutralizing Activity ◽  
Age Dependent ◽  
Induced Immunity

Since mRNA vaccines utilize wild-type SARS-CoV-2 spike protein as an antigen, there are potential concerns about acquiring immunity to variants of this virus. The neutralizing activity in BNT162b2-vaccinated individuals was higher against the wild-type virus than against its variants; this effect was more apparent in older age groups.

scholarly journals Cross-Neutralizing Activity of Monoclonal Antibodies Against N501Y Mutant Strain of SARS-CoV-2

2020 ◽  
Vol 9 (4) ◽  
pp. 41-45
Author(s):  
Ruxia Ding ◽  
Haixin Wang ◽  
Yi Yang ◽  
Liangshu Xie ◽  
Li Zhang ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Mutant Strain ◽  
Wild Type Strain ◽  
Neutralization Assay ◽  
Spike Protein ◽  
Wild Type ◽  
Neutralizing Activity ◽  
Theory Result ◽  
Global Concern ◽  
The Uk

The dominant N501Y mutation in the spike protein that SARS-CoV-2 virus uses to bind to the human ACE2 receptor were found in the UK, which has aroused global concern and worried. Mutations in spike protein may, in theory, result in more infectious and spreading more easily. In order to evaluate the broad-spectrum protective effect of the monoclonal antibodies(mAbs), we compared the neutralization activities of six prepared mAbs against SARS-CoV-2 with pseudovirus neutralization assay. Only one of them showed a decrease of 6 folds in neutralizing activity to N501Y mutant strain, compared with the wild type strain. We should continue to monitor emergence of new variants in different regions to study their infectivity and neutralization effect.

scholarly journals Sensitivity of two SARS-CoV-2 variants with spike protein mutations to neutralising antibodies

Virus Genes ◽  
2021 ◽  
Author(s):  
Katharina Müller ◽  
Philipp Girl ◽  
Andreas Giebl ◽  
Stefanie Gruetzner ◽  
Markus Antwerpen ◽  
...  
Keyword(s):  
Immune Response ◽  
Humoral Immune Response ◽  
Point Of View ◽  
Spike Protein ◽  
Wild Type ◽  
Serum Samples ◽  
Antibody Treatment ◽  
Neutralising Antibodies ◽  
Humoral Immune ◽  
Protein Mutations

AbstractSARS-CoV-2 infections elicit a humoral immune response capable of neutralising the virus. However, multiple variants have emerged with mutations in the spike protein amongst others, the key target of neutralising antibodies. We evaluated the neutralising efficacy of 89 serum samples from patients, infected with SARS-CoV-2 in the beginning of 2020, against two virus variants isolated from acutely infected patients and harbouring spike protein mutations. One isolate was assigned to lineage B.1.351 (MUC-IMB-B.1.351) whilst the other (MUC-484) was isolated from an immunocompromised patient, sharing some but not all mutations with B.1.351 and representing a transitional variant. Both variants showed a significant reduction in neutralisation sensitivity compared to wild-type SARS-CoV-2 with MUC-IMB-B.1.351 being almost completely resistant to neutralisation. The observed reduction in neutralising activity of wild-type-specific antibodies against both variants suggests that individual mutations in the spike protein are sufficient to confer a potent escape from the humoral immune response. In addition, the effect of escape mutations seems to accumulate, so that more heavily mutated variants show a greater loss of sensitivity to neutralisation up to complete insensitivity as observed for MUC-IMB-B.1.351. From a clinical point of view, this might affect the efficacy of (monoclonal) antibody treatment of patients with prolonged infections as well as patients infected with variants other than the donor. At the same, this could also negatively influence the efficacy of current vaccines (as they are based on wild-type spike protein) emphasising the need to thoroughly surveil the emergence and distribution of variants and adapt vaccines and therapeutics accordingly.

scholarly journals Detection of pseudorabies virus antibody in swine oral fluid using a serum whole-virus indirect ELISA

2020 ◽  
Vol 32 (4) ◽  
pp. 535-541
Author(s):  
Ting-Yu Cheng ◽  
Alexandra Buckley ◽  
Albert Van Geelen ◽  
Kelly Lager ◽  
Alexandra Henao-Díaz ◽  
...  
Keyword(s):  
Oral Fluid ◽  
Pseudorabies Virus ◽  
Negative Control ◽  
Wild Type Virus ◽  
Wild Type ◽  
Serum Samples ◽  
Anamnestic Response ◽  
Treatment Groups ◽  
Oral Fluids ◽  
Area Under Roc Curve

We evaluated the detection of pseudorabies virus (PRV) antibodies in swine oral fluid. Oral fluid and serum samples were obtained from 40 pigs allocated to 4 treatment groups (10 pigs/group): negative control (NC); wild-type PRV inoculation (PRV 3CR Ossabaw; hereafter PRV); PRV vaccination (Ingelvac Aujeszky MLV; Boehringer Ingelheim; hereafter MLV); and PRV vaccination followed by PRV inoculation at 21 d post-vaccination (MLV-PRV). Using a serum PRV whole-virus indirect IgG ELISA (Idexx Laboratories) adapted to the oral fluid matrix, PRV antibody was detected in oral fluid samples from treatment groups PRV, MLV, and MLV-PRV in a pattern similar to serum. Vaccination alone produced a low oral fluid antibody response (groups MLV and MLV-PRV), but a strong anamnestic response was observed following challenge with wild-type virus (group PRV). Analyses of the oral fluid PRV indirect IgG ELISA results showed good binary diagnostic performance (area under ROC curve = 93%) and excellent assay repeatability (intra-class correlation coefficient = 99.3%). The demonstrable presence of PRV antibodies in swine oral fluids suggests the possible use of oral fluids in pseudorabies surveillance.

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