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2.
PLoS Pathog ; 18(7): e1010691, 2022 07.
Article in English | MEDLINE | ID: covidwho-1951570

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) marks the third novel ß-coronavirus to cause significant human mortality in the last two decades. Although vaccines are available, too few have been administered worldwide to keep the virus in check and to prevent mutations leading to immune escape. To determine if antibodies could be identified with universal coronavirus activity, plasma from convalescent subjects was screened for IgG against a stabilized pre-fusion SARS-CoV-2 spike S2 domain, which is highly conserved between human ß-coronavirus. From these subjects, several S2-specific human monoclonal antibodies (hmAbs) were developed that neutralized SARS-CoV-2 with recognition of all variants of concern (VoC) tested (Beta, Gamma, Delta, Epsilon, and Omicron). The hmAb 1249A8 emerged as the most potent and broad hmAb, able to recognize all human ß-coronavirus and neutralize SARS-CoV and MERS-CoV. 1249A8 demonstrated significant prophylactic activity in K18 hACE2 mice infected with SARS-CoV-2 lineage A and lineage B Beta, and Omicron VoC. 1249A8 delivered as a single 4 mg/kg intranasal (i.n.) dose to hamsters 12 hours following infection with SARS-CoV-2 Delta protected them from weight loss, with therapeutic activity further enhanced when combined with 1213H7, an S1-specific neutralizing hmAb. As little as 2 mg/kg of 1249A8 i.n. dose 12 hours following infection with SARS-CoV Urbani strain, protected hamsters from weight loss and significantly reduced upper and lower respiratory viral burden. These results indicate in vivo cooperativity between S1 and S2 specific neutralizing hmAbs and that potent universal coronavirus neutralizing mAbs with therapeutic potential can be induced in humans and can guide universal coronavirus vaccine development.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Animals , Antibodies, Monoclonal/pharmacology , Antibodies, Neutralizing/pharmacology , Antibodies, Viral , COVID-19/therapy , COVID-19 Vaccines , Humans , Mice , SARS-CoV-2 , Weight Loss
3.
MAbs ; 14(1): 2047144, 2022.
Article in English | MEDLINE | ID: covidwho-1740685

ABSTRACT

There remains an unmet need for globally deployable, low-cost therapeutics for the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Previously, we reported on the isolation and in vitro characterization of a potent single-domain nanobody, NIH-CoVnb-112, specific for the receptor-binding domain (RBD) of SARS-CoV-2. Here, we report on the molecular basis for the observed broad in vitro neutralization capability of NIH-CoVnb-112 against variant SARS-CoV-2 pseudoviruses. The structure of NIH-CoVnb-112 bound to SARS-CoV-2 RBD reveals a large contact surface area overlapping the angiotensin converting enzyme 2 (ACE2) binding site, which is largely unencumbered by the common RBD mutations. In an in vivo pilot study, we demonstrate effective reductions in weight loss, viral burden, and lung pathology in a Syrian hamster model of COVID-19 following nebulized delivery of NIH-CoVnb-112. These findings support the further development of NIH-CoVnb-112 as a potential adjunct preventative therapeutic for the treatment of SARS-CoV-2 infection.Abbreviations: ACE2 - angiotensin converting enzyme 2BSA - buried surface areaCDR - complementary determining regionRBD - receptor binding domainRBM - receptor-binding motifSARS-CoV-2 - severe acute respiratory syndrome coronavirus 2.


Subject(s)
Antibodies, Viral/metabolism , Broadly Neutralizing Antibodies/metabolism , COVID-19/immunology , Lung/pathology , SARS-CoV-2/physiology , Single-Domain Antibodies/metabolism , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Viral/immunology , Binding Sites/genetics , Broadly Neutralizing Antibodies/immunology , Cricetinae , Disease Models, Animal , Humans , Mesocricetus , Nebulizers and Vaporizers , Protein Binding , Single-Domain Antibodies/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Load
4.
Mol Ther ; 30(5): 1897-1912, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1586240

ABSTRACT

RNA vaccines have demonstrated efficacy against SARS-CoV-2 in humans, and the technology is being leveraged for rapid emergency response. In this report, we assessed immunogenicity and, for the first time, toxicity, biodistribution, and protective efficacy in preclinical models of a two-dose self-amplifying messenger RNA (SAM) vaccine, encoding a prefusion-stabilized spike antigen of SARS-CoV-2 Wuhan-Hu-1 strain and delivered by lipid nanoparticles (LNPs). In mice, one immunization with the SAM vaccine elicited a robust spike-specific antibody response, which was further boosted by a second immunization, and effectively neutralized the matched SARS-CoV-2 Wuhan strain as well as B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta) variants. High frequencies of spike-specific germinal center B, Th0/Th1 CD4, and CD8 T cell responses were observed in mice. Local tolerance, potential systemic toxicity, and biodistribution of the vaccine were characterized in rats. In hamsters, the vaccine candidate was well-tolerated, markedly reduced viral load in the upper and lower airways, and protected animals against disease in a dose-dependent manner, with no evidence of disease enhancement following SARS-CoV-2 challenge. Therefore, the SARS-CoV-2 SAM (LNP) vaccine candidate has a favorable safety profile, elicits robust protective immune responses against multiple SARS-CoV-2 variants, and has been advanced to phase 1 clinical evaluation (NCT04758962).


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Cricetinae , Humans , Liposomes , Mice , Nanoparticles , RNA, Messenger , Rats , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Tissue Distribution
5.
COVID ; 1(3):602-607, 2021.
Article in English | MDPI | ID: covidwho-1512153

ABSTRACT

SARS-CoV-2 is frequently transmitted by aerosol, and the sterilization of the virus in airflows has numerous potential applications. We evaluated a UV-C illuminator similar to what might be incorporated into tubing of a mechanical ventilator for its ability to block transmission of the airborne virus from infected to naïve hamsters. Hamsters protected by the UV system were consistently protected from infection, whereas non-protected hamsters uniformly became infected and displayed virus shedding and high burdens of virus in respiratory tissues. The efficiency and speed with which the virus in flowing air was inactivated using this system suggests several applications for mitigating transmission of this virus.

6.
Emerg Microbes Infect ; 10(1): 2199-2201, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1505680

ABSTRACT

We report pilot studies to evaluate the susceptibility of common domestic livestock (cattle, sheep, goat, alpaca, rabbit, and horse) to intranasal infection with SARS-CoV-2. None of the infected animals shed infectious virus via nasal, oral, or faecal routes, although viral RNA was detected in several animals. Further, neutralizing antibody titres were low or non-existent one month following infection. These results suggest that domestic livestock are unlikely to contribute to SARS-CoV-2 epidemiology.


Subject(s)
COVID-19/veterinary , Host Specificity , Livestock/virology , SARS-CoV-2/pathogenicity , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/virology , Camelids, New World/virology , Cattle/virology , Chlorocebus aethiops , Disease Reservoirs/virology , Goats/virology , Horses/virology , Host Specificity/immunology , Humans , Nasal Cavity/virology , RNA, Viral/analysis , Rabbits/virology , Rectum/virology , Respiratory System/virology , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Sheep/virology , Species Specificity , Vero Cells , Virus Shedding , Viscera/virology
7.
Proc Natl Acad Sci U S A ; 118(44)2021 11 02.
Article in English | MEDLINE | ID: covidwho-1493339

ABSTRACT

SARS-CoV-2 spillback from humans into domestic and wild animals has been well documented, and an accumulating number of studies illustrate that human-to-animal transmission is widespread in cats, mink, deer, and other species. Experimental inoculations of cats, mink, and ferrets have perpetuated transmission cycles. We sequenced full genomes of Vero cell-expanded SARS-CoV-2 inoculum and viruses recovered from cats (n = 6), dogs (n = 3), hamsters (n = 3), and a ferret (n = 1) following experimental exposure. Five nonsynonymous changes relative to the USA-WA1/2020 prototype strain were near fixation in the stock used for inoculation but had reverted to wild-type sequences at these sites in dogs, cats, and hamsters within 1- to 3-d postexposure. A total of 14 emergent variants (six in nonstructural genes, six in spike, and one each in orf8 and nucleocapsid) were detected in viruses recovered from animals. This included substitutions in spike residues H69, N501, and D614, which also vary in human lineages of concern. Even though a live virus was not cultured from dogs, substitutions in replicase genes were detected in amplified sequences. The rapid selection of SARS-CoV-2 variants in vitro and in vivo reveals residues with functional significance during host switching. These observations also illustrate the potential for spillback from animal hosts to accelerate the evolution of new viral lineages, findings of particular concern for dogs and cats living in households with COVID-19 patients. More generally, this glimpse into viral host switching reveals the unrealized rapidity and plasticity of viral evolution in experimental animal model systems.


Subject(s)
COVID-19/virology , Evolution, Molecular , SARS-CoV-2/genetics , Selection, Genetic , Animals , COVID-19/veterinary , Cats , Chlorocebus aethiops , Dogs , Ferrets , Gene Frequency , Pets/virology , SARS-CoV-2/pathogenicity , Vero Cells , Viral Proteins/genetics
8.
NPJ Vaccines ; 6(1): 122, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1475297

ABSTRACT

Early in the SARS-CoV-2 pandemic concerns were raised regarding infection of new animal hosts and the effect on viral epidemiology. Infection of other animals could be detrimental by causing clinical disease, allowing further mutations, and bares the risk for the establishment of a non-human reservoir. Cats were the first reported animals susceptible to natural and experimental infection with SARS-CoV-2. Given the concerns these findings raised, and the close contact between humans and cats, we aimed to develop a vaccine candidate that could reduce SARS-CoV-2 infection and in addition to prevent spread among cats. Here we report that a Replicon Particle (RP) vaccine based on Venezuelan equine encephalitis virus, known to be safe and efficacious in a variety of animal species, could induce neutralizing antibody responses in guinea pigs and cats. The design of the SARS-CoV-2 spike immunogen was critical in developing a strong neutralizing antibody response. Vaccination of cats was able to induce high neutralizing antibody responses, effective also against the SARS-CoV-2 B.1.1.7 variant. Interestingly, in contrast to control animals, the infectious virus could not be detected in oropharyngeal or nasal swabs of vaccinated cats after SARS-CoV-2 challenge. Correspondingly, the challenged control cats spread the virus to in-contact cats whereas the vaccinated cats did not transmit the virus. The results show that the RP vaccine induces protective immunity preventing SARS-CoV-2 infection and transmission. These data suggest that this RP vaccine could be a multi-species vaccine useful to prevent infection and spread to and between animals should that approach be required.

9.
Cell Rep ; 37(2): 109822, 2021 10 12.
Article in English | MEDLINE | ID: covidwho-1433046

ABSTRACT

Potent neutralizing monoclonal antibodies are one of the few agents currently available to treat COVID-19. SARS-CoV-2 variants of concern (VOCs) that carry multiple mutations in the viral spike protein can exhibit neutralization resistance, potentially affecting the effectiveness of some antibody-based therapeutics. Here, the generation of a diverse panel of 91 human, neutralizing monoclonal antibodies provides an in-depth structural and phenotypic definition of receptor binding domain (RBD) antigenic sites on the viral spike. These RBD antibodies ameliorate SARS-CoV-2 infection in mice and hamster models in a dose-dependent manner and in proportion to in vitro, neutralizing potency. Assessing the effect of mutations in the spike protein on antibody recognition and neutralization highlights both potent single antibodies and stereotypic classes of antibodies that are unaffected by currently circulating VOCs, such as B.1.351 and P.1. These neutralizing monoclonal antibodies and others that bind analogous epitopes represent potentially useful future anti-SARS-CoV-2 therapeutics.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , Antibodies, Neutralizing/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Angiotensin-Converting Enzyme 2/ultrastructure , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Neutralizing/ultrastructure , Antibodies, Viral/immunology , COVID-19/immunology , Cricetinae , Cryoelectron Microscopy/methods , Epitopes/immunology , Female , Humans , Male , Mice , Mice, Inbred C57BL , Middle Aged , Neutralization Tests , Protein Binding/physiology , Receptors, Virus/metabolism , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
10.
Emerg Infect Dis ; 27(8): 2073-2080, 2021 08.
Article in English | MEDLINE | ID: covidwho-1319583

ABSTRACT

Wild animals have been implicated as the origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but it is largely unknown how the virus affects most wildlife species and if wildlife could ultimately serve as a reservoir for maintaining the virus outside the human population. We show that several common peridomestic species, including deer mice, bushy-tailed woodrats, and striped skunks, are susceptible to infection and can shed the virus in respiratory secretions. In contrast, we demonstrate that cottontail rabbits, fox squirrels, Wyoming ground squirrels, black-tailed prairie dogs, house mice, and racoons are not susceptible to SARS-CoV-2 infection. Our results expand the knowledge base of susceptible species and provide evidence that human-wildlife interactions could result in continued transmission of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Animals, Wild , Disease Susceptibility , Humans , Mammals , Mice
11.
Vaccines (Basel) ; 9(4)2021 Apr 01.
Article in English | MEDLINE | ID: covidwho-1167780

ABSTRACT

The COVID-19 pandemic has generated intense interest in the rapid development and evaluation of vaccine candidates for this disease and other emerging diseases. Several novel methods for preparing vaccine candidates are currently undergoing clinical evaluation in response to the urgent need to prevent the spread of COVID-19. In many cases, these methods rely on new approaches for vaccine production and immune stimulation. We report on the use of a novel method (SolaVAX) for production of an inactivated vaccine candidate and the testing of that candidate in a hamster animal model for its ability to prevent infection upon challenge with SARS-CoV-2 virus. The studies employed in this work included an evaluation of the levels of neutralizing antibody produced post-vaccination, levels of specific antibody sub-types to RBD and spike protein that were generated, evaluation of viral shedding post-challenge, flow cytometric and single cell sequencing data on cellular fractions and histopathological evaluation of tissues post-challenge. The results from this preliminary evaluation provide insight into the immunological responses occurring as a result of vaccination with the proposed vaccine candidate and the impact that adjuvant formulations, specifically developed to promote Th1 type immune responses, have on vaccine efficacy and protection against infection following challenge with live SARS-CoV-2. This data may have utility in the development of effective vaccine candidates broadly. Furthermore, the results of this preliminary evaluation suggest that preparation of a whole virion vaccine for COVID-19 using this specific photochemical method may have potential utility in the preparation of one such vaccine candidate.

12.
NPJ Vaccines ; 6(1): 47, 2021 Mar 30.
Article in English | MEDLINE | ID: covidwho-1159813

ABSTRACT

To generate an inexpensive readily manufactured COVID-19 vaccine, we employed the LVS ΔcapB vector platform, previously used to generate potent candidate vaccines against Select Agent diseases tularemia, anthrax, plague, and melioidosis. Vaccines expressing SARS-CoV-2 structural proteins are constructed using the LVS ΔcapB vector, a highly attenuated replicating intracellular bacterium, and evaluated for efficacy in golden Syrian hamsters, which develop severe COVID-19-like disease. Hamsters immunized intradermally or intranasally with a vaccine co-expressing the Membrane and Nucleocapsid proteins and challenged 5 weeks later with a high dose of SARS-CoV-2 are protected against severe weight loss and lung pathology and show reduced viral loads in the oropharynx and lungs. Protection correlates with anti-Nucleocapsid antibody. This potent vaccine should be safe; inexpensive; easily manufactured, stored, and distributed; and given the high homology between Membrane and Nucleocapsid proteins of SARS-CoV and SARS-CoV-2, potentially serve as a universal vaccine against the SARS subset of pandemic causing ß-coronaviruses.

13.
J Exp Med ; 218(3)2021 03 01.
Article in English | MEDLINE | ID: covidwho-1044017

ABSTRACT

SARS-CoV-2, the causative agent of COVID-19, has been responsible for over 42 million infections and 1 million deaths since its emergence in December 2019. There are few therapeutic options and no approved vaccines. Here, we examine the properties of highly potent human monoclonal antibodies (hu-mAbs) in a Syrian hamster model of SARS-CoV-2 and in a mouse-adapted model of SARS-CoV-2 infection (SARS-CoV-2 MA). Antibody combinations were effective for prevention and in therapy when administered early. However, in vitro antibody neutralization potency did not uniformly correlate with in vivo protection, and some hu-mAbs were more protective in combination in vivo. Analysis of antibody Fc regions revealed that binding to activating Fc receptors contributes to optimal protection against SARS-CoV-2 MA. The data indicate that intact effector function can affect hu-mAb protective activity and that in vivo testing is required to establish optimal hu-mAb combinations for COVID-19 prevention.


Subject(s)
Antibodies, Monoclonal, Murine-Derived , Antibodies, Neutralizing , Antibodies, Viral , Betacoronavirus/immunology , Coronavirus Infections , Pandemics , Pneumonia, Viral , Animals , Antibodies, Monoclonal, Murine-Derived/immunology , Antibodies, Monoclonal, Murine-Derived/pharmacology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/pharmacology , Antibodies, Viral/immunology , Antibodies, Viral/pharmacology , COVID-19 , Cell Line , Coronavirus Infections/immunology , Coronavirus Infections/therapy , Female , Humans , Mesocricetus , Mice , Mice, Inbred BALB C , Pneumonia, Viral/immunology , Pneumonia, Viral/therapy , SARS-CoV-2
14.
Proc Natl Acad Sci U S A ; 117(42): 26382-26388, 2020 10 20.
Article in English | MEDLINE | ID: covidwho-807892

ABSTRACT

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached nearly every country in the world with extraordinary person-to-person transmission. The most likely original source of the virus was spillover from an animal reservoir and subsequent adaptation to humans sometime during the winter of 2019 in Wuhan Province, China. Because of its genetic similarity to SARS-CoV-1, it is probable that this novel virus has a similar host range and receptor specificity. Due to concern for human-pet transmission, we investigated the susceptibility of domestic cats and dogs to infection and potential for infected cats to transmit to naive cats. We report that cats are highly susceptible to infection, with a prolonged period of oral and nasal viral shedding that is not accompanied by clinical signs, and are capable of direct contact transmission to other cats. These studies confirm that cats are susceptible to productive SARS-CoV-2 infection, but are unlikely to develop clinical disease. Further, we document that cats developed a robust neutralizing antibody response that prevented reinfection following a second viral challenge. Conversely, we found that dogs do not shed virus following infection but do seroconvert and mount an antiviral neutralizing antibody response. There is currently no evidence that cats or dogs play a significant role in human infection; however, reverse zoonosis is possible if infected owners expose their domestic pets to the virus during acute infection. Resistance to reinfection holds promise that a vaccine strategy may protect cats and, by extension, humans.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Pneumonia, Viral/virology , Animals , Animals, Domestic , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antigens, Viral/immunology , Betacoronavirus/immunology , COVID-19 , Cats , Coronavirus Infections/pathology , Coronavirus Infections/transmission , Disease Models, Animal , Dogs , Female , Male , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/transmission , SARS-CoV-2 , Virus Shedding
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