scholarly journals SARS-CoV-2 Reinfection in a Healthcare Worker Despite the Presence of Detectable Neutralizing Antibodies

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 661
Author(s):  
Thomas Theo Brehm ◽  
Susanne Pfefferle ◽  
Ronald von Possel ◽  
Robin Kobbe ◽  
Dominik Nörz ◽  
...  
Keyword(s):  
Healthcare Worker ◽  
Neutralizing Antibodies ◽  
Infectious Virus ◽  
Viral Escape ◽  
Disease Course ◽  
Live Virus ◽  
Virus Variant ◽  
Virus Shedding ◽  
Mild Disease ◽  
Infection Episode

So far, only a few reports about reinfections with SARS-CoV-2 have been published, and they often lack detailed immunological and virological data. We report about a SARS-CoV-2 reinfection with a genetically distinct SARS-CoV-2 variant in an immunocompetent female healthcare worker that has led to a mild disease course. No obvious viral escape mutations were observed in the second virus variant. The infectious virus was shed from the patient during the second infection episode despite the presence of neutralizing antibodies in her blood. Our data indicate that a moderate immune response after the first infection, but not a viral escape, did allow for reinfection and live virus shedding.

scholarly journals The Road towards Polyclonal Anti-SARS-CoV-2 Immunoglobulins (Hyperimmune Serum) for Passive Immunization in COVID-19

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 144
Author(s):  
Daniele Focosi ◽  
Marco Tuccori ◽  
Massimo Franchini
Keyword(s):  
Neutralizing Antibodies ◽  
Passive Immunization ◽  
Spike Protein ◽  
Controlled Trials ◽  
Disease Course ◽  
Early Disease ◽  
Hyperimmune Serum ◽  
The Road ◽  
Randomized Controlled ◽  
Pros And Cons

Effective treatments specific for COVID-19 are still lacking. In the setting of passive immunotherapies based on neutralizing antibodies (nAbs), randomized controlled trials of COVID-19 convalescent plasma (CCP) anti-SARS-CoV-2 Spike protein monoclonal antibodies (mAb), which have been granted emergency use authorization, have suggested benefit in early disease course (less than 72 hours from symptoms and seronegative). Meanwhile, polyclonal immunoglobulins (i.e., hyperimmune serum), derived either from CCP donations or from animals immunized with SARS-CoV-2 antigens, are likely to become the next nAb-derived candidate. We here discuss the pros and cons of hyperimmune serum versus CCP and mAb, and summarize the ongoing clinical trials of COVID-19 hyperimmune sera.

scholarly journals Evaluation of a Pseudovirus Neutralization Assay for SARS-CoV-2 and Correlation with Live Virus-Based Micro Neutralization Assay

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 994
Author(s):  
Ahmed Majdi K. Tolah ◽  
Sayed S. Sohrab ◽  
Khaled Majdi K. Tolah ◽  
Ahmed M. Hassan ◽  
Sherif A. El-Kafrawy ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Epidemiological Studies ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Live Virus ◽  
Spike Gene ◽  
Microneutralization Assay ◽  
Viral Particles ◽  
Reliable Performance ◽  
Prior Infection

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

scholarly journals A surrogate virus neutralization test to quantify antibody-mediated inhibition of SARS-CoV-2 in finger stick dried blood spot samples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amelia E. Sancilio ◽  
Richard T. D’Aquila ◽  
Elizabeth M. McNally ◽  
Matthew P. Velez ◽  
Michael G. Ison ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Venous Blood ◽  
Host Cells ◽  
Dried Blood Spot ◽  
Blood Collection ◽  
Widespread Application ◽  
Live Virus ◽  
Dilution Series ◽  
Wide Range ◽  
Blood Spot

AbstractThe spike protein of SARS-CoV-2 engages the human angiotensin-converting enzyme 2 (ACE2) receptor to enter host cells, and neutralizing antibodies are effective at blocking this interaction to prevent infection. Widespread application of this important marker of protective immunity is limited by logistical and technical challenges associated with live virus methods and venous blood collection. To address this gap, we validated an immunoassay-based method for quantifying neutralization of the spike-ACE2 interaction in a single drop of capillary whole blood, collected on filter paper as a dried blood spot (DBS) sample. Samples are eluted overnight and incubated in the presence of spike antigen and ACE2 in a 96-well solid phase plate. Competitive immunoassay with electrochemiluminescent label is used to quantify neutralizing activity. The following measures of assay performance were evaluated: dilution series of confirmed positive and negative samples, agreement with results from matched DBS-serum samples, analysis of results from DBS samples with known COVID-19 status, and precision (intra-assay percent coefficient of variation; %CV) and reliability (inter-assay; %CV). Dilution series produced the expected pattern of dose–response. Agreement between results from serum and DBS samples was high, with concordance correlation = 0.991. Analysis of three control samples across the measurement range indicated acceptable levels of precision and reliability. Median % surrogate neutralization was 46.9 for PCR confirmed convalescent COVID-19 samples and 0.1 for negative samples. Large-scale testing is important for quantifying neutralizing antibodies that can provide protection against COVID-19 in order to estimate the level of immunity in the general population. DBS provides a minimally-invasive, low cost alternative to venous blood collection, and this scalable immunoassay-based method for quantifying inhibition of the spike-ACE2 interaction can be used as a surrogate for virus-based assays to expand testing across a wide range of settings and populations.

scholarly journals Neutralizing antibodies against SARS-CoV-2: current understanding, challenge and perspective

2020 ◽  
Vol 3 (4) ◽  
pp. 285-299
Author(s):  
Yang Huang ◽  
Hui Sun ◽  
Hai Yu ◽  
Shaowei Li ◽  
Qingbing Zheng ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Therapeutic Potential ◽  
Therapeutic Interventions ◽  
Viral Escape ◽  
Global Burden ◽  
Health Crisis ◽  
The Us ◽  
Preclinical And Clinical Studies ◽  
Insight Into ◽  
Rapid Emergence

Abstract The rapid emergence of Coronavirus disease-2019 (COVID-19) caused by severe acute respiratory syndrome 2 coronavirus (SARS-CoV-2) as a pandemic that presents an urgent human health crisis. Many SARS-CoV-2 neutralizing antibodies (NAbs) were developed with efficient therapeutic potential. NAbs-based therapeutics against SARS-CoV-2 are being expedited to preclinical and clinical studies with two antibody drugs, LY3819253 (LY-CoV555) and REGN-COV2 (REGN10933 and REGN10987), approved by the US Food and Drug Administration for emergency use authorization for treating COVID-19. In this review, we provide a systemic overview of SARS-CoV-2 specific or cross-reactive NAbs and discuss their structures, functions and neutralization mechanisms. We provide insight into how these NAbs specific recognize the spike protein of SARS-CoV-2 or cross-react to other CoVs. We also summarize the challenges of NAbs therapeutics such as antibody-dependent enhancement and viral escape mutations. Such evidence is urgently needed to the development of antibody therapeutic interventions that are likely required to reduce the global burden of COVID-19.

scholarly journals SARS-CoV-2 RBD trimer protein adjuvanted with Alum-3M-052 protects from SARS-CoV-2 infection and immune pathology in the lung

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nanda Kishore Routhu ◽  
Narayanaiah Cheedarla ◽  
Venkata Satish Bollimpelli ◽  
Sailaja Gangadhara ◽  
Venkata Viswanadh Edara ◽  
...  
Keyword(s):  
Antibody Response ◽  
Antibody Titer ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Significant Loss ◽  
Lung Pathology ◽  
Live Virus ◽  
Suitable Candidate ◽  
Immune Pathology

AbstractThere is a great need for the development of vaccines that induce potent and long-lasting protective immunity against SARS-CoV-2. Multimeric display of the antigen combined with potent adjuvant can enhance the potency and longevity of the antibody response. The receptor binding domain (RBD) of the spike protein is a primary target of neutralizing antibodies. Here, we developed a trimeric form of the RBD and show that it induces a potent neutralizing antibody response against live virus with diverse effector functions and provides protection against SARS-CoV-2 challenge in mice and rhesus macaques. The trimeric form induces higher neutralizing antibody titer compared to monomer with as low as 1μg antigen dose. In mice, adjuvanting the protein with a TLR7/8 agonist formulation alum-3M-052 induces 100-fold higher neutralizing antibody titer and superior protection from infection compared to alum. SARS-CoV-2 infection causes significant loss of innate cells and pathology in the lung, and vaccination protects from changes in innate cells and lung pathology. These results demonstrate RBD trimer protein as a suitable candidate for vaccine against SARS-CoV-2.

scholarly journals Experimental Infection of Amblyomma americanum (Acari: Ixodidae) With Bourbon Virus (Orthomyxoviridae: Thogotovirus)

2020 ◽  
Author(s):  
Marvin S Godsey ◽  
Dominic Rose ◽  
Kristin L Burkhalter ◽  
Nicole Breuner ◽  
Angela M Bosco-Lauth ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Vector Competence ◽  
Blood Feeding ◽  
Human Case ◽  
Amblyomma Americanum ◽  
Live Virus ◽  
Active Life ◽  
Series Of Experiments ◽  
Transstadial Transmission ◽  
Very High

Abstract Following the recent discovery of Bourbon virus (BRBV) as a human pathogen, and the isolation of the virus from Amblyomma americanum (L.) collected near the location of a fatal human case, we undertook a series of experiments to assess the laboratory vector competence of this tick species for BRBV. Larval ticks were infected using an immersion technique, and transstadial transmission of virus to the nymphal and then to the adult stages was demonstrated. Transstadially infected nymphs transmitted virus to adult ticks at very high rates during cofeeding, indicating the presence of infectious virus in the saliva of engorging ticks. Vertical transmission by transstadially infected females to their progeny occurred, but at a low rate. Rabbits fed on by infected ticks of all active life stages developed high titers of antibody to the virus, demonstrating host exposure to BRBV antigens/live virus during tick blood feeding. These results demonstrate that A. americanum is a competent vector of BRBV and indicate that cofeeding could be critical for enzootic maintenance.

scholarly journals In Silico Investigation of the New UK (B.1.1.7) and South African (501Y.V2) SARS-CoV-2 Variants with a Focus at the ACE2–Spike RBD Interface

2021 ◽  
Vol 22 (4) ◽  
pp. 1695
Author(s):  
Bruno O. Villoutreix ◽  
Vincent Calvez ◽  
Anne-Geneviève Marcelin ◽  
Abdel-Majid Khatib
Keyword(s):  
Amino Acid ◽  
South African ◽  
In Silico ◽  
Neutralizing Antibodies ◽  
Viral Escape ◽  
Spike Protein ◽  
Amino Acid Substitutions ◽  
The South ◽  
African Strain ◽  
The Uk

SARS-CoV-2 exploits angiotensin-converting enzyme 2 (ACE2) as a receptor to invade cells. It has been reported that the UK and South African strains may have higher transmission capabilities, eventually in part due to amino acid substitutions on the SARS-CoV-2 Spike protein. The pathogenicity seems modified but is still under investigation. Here we used the experimental structure of the Spike RBD domain co-crystallized with part of the ACE2 receptor, several in silico methods and numerous experimental data reported recently to analyze the possible impacts of three amino acid replacements (Spike K417N, E484K, N501Y) with regard to ACE2 binding. We found that the N501Y replacement in this region of the interface (present in both the UK and South African strains) should be favorable for the interaction with ACE2, while the K417N and E484K substitutions (South African strain) would seem neutral or even unfavorable. It is unclear if the N501Y substitution in the South African strain could counterbalance the K417N and E484K Spike replacements with regard to ACE2 binding. Our finding suggests that the UK strain should have higher affinity toward ACE2 and therefore likely increased transmissibility and possibly pathogenicity. If indeed the South African strain has a high transmission level, this could be due to the N501Y replacement and/or to substitutions in regions located outside the direct Spike–ACE2 interface but not so much to the K417N and E484K replacements. Yet, it should be noted that amino acid changes at Spike position 484 can lead to viral escape from neutralizing antibodies. Further, these amino acid substitutions do not seem to induce major structural changes in this region of the Spike protein. This structure–function study allows us to rationalize some observations made for the UK strain but raises questions for the South African strain.

scholarly journals Experimental Infection of Reindeer with Cervid Herpesvirus 2

2009 ◽  
Vol 16 (12) ◽  
pp. 1758-1765 ◽  
Author(s):  
Carlos G. das Neves ◽  
Torill Mørk ◽  
Jacques Godfroid ◽  
Karen K. Sørensen ◽  
Eva Breines ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Rangifer Tarandus ◽  
Systemic Infection ◽  
Vaginal Swab ◽  
Mild Hyperthermia ◽  
Virus Shedding ◽  
Nasal Swabs ◽  
Vaginal Swabs ◽  
Positive Immunostaining ◽  
Serological Data

ABSTRACT Cervid herpesvirus 2 (CvHV2) has been isolated from reindeer (Rangifer tarandus tarandus), and serological data indicate that in reindeer this virus is endemic in Fennoscandia, Alaska, Canada, and Greenland. CvHV2 has been described as a cause of subclinical genital infections in reindeer, but little information on primary infections exists. In this study, six seronegative and presumably pregnant reindeer were allocated to one of two groups. Two animals were inoculated with CvHV2 intratracheally, and two animals intravaginally, with one control animal in each group receiving sterile water. Mild hyperthermia and serous discharges from the vagina and nose were observed. No abortions were recorded, but one calf died shortly after birth. Inoculated animals seroconverted and had neutralizing antibodies after days 7 to 10 postinfection. CvHV2 was detected by PCR in nasal and vaginal swabs from animals in both groups but could be isolated only from nasal swabs in the respiratory group and from vaginal swabs in the genital group. CvHV2 was detected by PCR in various organs and tissues postmortem. In control animals, the virus could not be isolated in spite of PCR-positive nasal and vaginal swab samples and some degree of positive immunostaining. One of the animals that were inoculated intratracheally developed a hemorrhagic, necrotizing bronchopneumonia, which was CvHV2 positive by PCR and immunohistochemistry. We conclude that CvHV2 can cause systemic infection, that both genital and respiratory inoculations can lead to virus shedding, and that the virus can infect the fetus in utero.

scholarly journals Quantitative measurement of infectious virus in SARS-CoV-2 Alpha, Delta and Epsilon variants reveals higher infectivity (viral titer:RNA ratio) in clinical samples containing the Delta and Epsilon variants.

2021 ◽  
Author(s):  
Hannah W Despres ◽  
Margaret G Mills ◽  
David J Shirley ◽  
Madaline M Schmidt ◽  
Meei-Li Huang ◽  
...  
Keyword(s):  
Quantitative Measurement ◽  
Infectious Virus ◽  
Viral Rna ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Genome Copy ◽  
Live Virus ◽  
High Degree ◽  
The Relationship ◽  
Rna Levels

ABSTRACT Background Novel SARS-CoV-2 Variants of Concern (VoC) pose a challenge to controlling the COVID-19 pandemic. Previous studies indicate that clinical samples collected from individuals infected with the Delta variant may contain higher levels of RNA than previous variants, but the relationship between viral RNA and infectious virus for individual variants is unknown. Methods We measured infectious viral titer (using a micro-focus forming assay) as well as total and subgenomic viral RNA levels (using RT-PCR) in a set of 165 clinical samples containing SARS-CoV-2 Alpha, Delta and Epsilon variants that were processed within two days of collection from the patient. Results We observed a high degree of variation in the relationship between viral titers and RNA levels. Despite the variability we observed for individual samples the overall infectivity differed among the three variants. Both Delta and Epsilon had significantly higher infectivity than Alpha, as measured by the number of infectious units per quantity of viral E gene RNA (6 and 4 times as much, p=0.0002 and 0.009 respectively) or subgenomic E RNA (11 and 7 times as much, p<0.0001 and 0.006 respectively). Conclusion In addition to higher viral RNA levels reported for the Delta variant, the infectivity (amount of replication competent virus per viral genome copy) may also be increased compared to Alpha. Measuring the relationship between live virus and viral RNA is an important step in assessing the infectivity of novel SARS-CoV-2 variants. An increase in the infectivity of the Delta variant may further explain increased spread and suggests a need for increased measures to prevent viral transmission.

scholarly journals A neutralizing monoclonal antibody-based competitive ELISA for classical swine fever C-strain post–vaccination monitoring

2019 ◽  
Author(s):  
Lihua Wang ◽  
Shijiang Mi ◽  
Rachel Madera ◽  
Llilianne Ganges ◽  
Manuel V. Borca ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Confidence Interval ◽  
Excellent Agreement ◽  
Neutralizing Antibodies ◽  
Vaccination Campaign ◽  
Classical Swine Fever ◽  
Enzyme Linked Immunosorbent Assay ◽  
Live Virus ◽  
Post Vaccination ◽  
Neutralizing Monoclonal Antibody

Abstract Background: Virus neutralization test (VNT) is widely used for serological survey of classical swine fever (CSF) and efficacy evaluation of CSF vaccines. However, VNT is a time consuming procedure that requires cell culture and live virus manipulation. C-strain CSF vaccine is the most frequently used vaccine for CSF control and prevention. In this study, we presented a neutralizing monoclonal antibody (mAb) based competitive enzyme-linked immunosorbent assay (cELISA) with the emphasis on the replacement of VNT for C-strain post–vaccination monitoring. Results: One monoclonal antibody (6B211) which has potent neutralizing activity against C-strain was generated. A novel cELISA was established and optimized based on the strategy that 6B211 can compete with C-strain induced neutralizing antibodies in pig serum to bind capture antigen C-strain E2. By testing C-strain VNT negative pig sera (n=445) and C-strain VNT positive pig sera (n=70), the 6B211 based cELSIA showed 100% sensitivity (95% confidence interval: 94.87 to 100%) and 100% specificity (95% confidence interval: 100 to 100%). The C-strain antibody can be detected in pigs as early as 7 days post vaccination with the cELISA. By testing pig sera (n=139) in parallel, the cELISA showed excellent agreement (Kappa=0.957) with VNT. The inhibition rate of serum samples in the cELISA is highly correlated with their titers in VNT (r 2 =0.903, p<0.001). In addition, intra- and inter-assays of the cELISA exhibited acceptable repeatability with low coefficient of variations (CVs). Conclusions: This novel cELISA demonstrated excellent agreement and high level correlation with VNT. It is a reliable tool for sero-monitoring of C-strain vaccination campaign because it is a rapid, simple, safe and cost effective assay that can be used to monitor vaccination-induced immune response at the population level.

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