scholarly journals Molecular basis of immune evasion by the delta and kappa SARS-CoV-2 variants

2021 ◽  
Author(s):  
Matthew McCallum ◽  
Alexandra C Walls ◽  
Kaitlin R Sprouse ◽  
John E Bowen ◽  
Laura Rosen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Immune Evasion ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Terminal Domain ◽  
Structural Framework ◽  
Ancestral Virus ◽  
Delta Receptor ◽  
The Impact

Worldwide SARS-CoV-2 transmission leads to the recurrent emergence of variants, such as the recently described B.1.617.1 (kappa), B.1.617.2 (delta) and B.1.617.2+ (delta+). The B.1.617.2 (delta) variant of concern is causing a new wave of infections in many countries, mostly affecting unvaccinated individuals, and has become globally dominant. We show that these variants dampen the in vitro potency of vaccine-elicited serum neutralizing antibodies and provide a structural framework for describing the impact of individual mutations on immune evasion. Mutations in the B.1.617.1 (kappa) and B.1.617.2 (delta) spike glycoproteins abrogate recognition by several monoclonal antibodies via alteration of key antigenic sites, including an unexpected remodeling of the B.1.617.2 (delta) N-terminal domain. The binding affinity of the B.1.617.1 (kappa) and B.1.617.2 (delta) receptor-binding domain for ACE2 is comparable to the ancestral virus whereas B.1.617.2+ (delta+) exhibits markedly reduced affinity. We describe a previously uncharacterized class of N-terminal domain-directed human neutralizing monoclonal antibodies cross-reacting with several variants of concern, revealing a possible target for vaccine development.

scholarly journals Generation of Neutralizing Human Monoclonal Antibodies against Parvovirus B19 Proteins

1999 ◽  
Vol 73 (3) ◽  
pp. 1974-1979 ◽  
Author(s):  
Andreas Gigler ◽  
Simone Dorsch ◽  
Andrea Hemauer ◽  
Constance Williams ◽  
Sonnie Kim ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Nonstructural Protein ◽  
Parvovirus B19 ◽  
Human Mabs ◽  
Unique Region ◽  
Neutralizing Activity

ABSTRACT Infections caused by human parvovirus B19 are known to be controlled mainly by neutralizing antibodies. To analyze the immune reaction against parvovirus B19 proteins, four cell lines secreting human immunoglobulin G monoclonal antibodies (MAbs) were generated from two healthy donors and one human immunodeficiency virus type 1-seropositive individual with high serum titers against parvovirus. One MAb is specific for nonstructural protein NS1 (MAb 1424), two MAbs are specific for the unique region of minor capsid protein VP1 (MAbs 1418-1 and 1418-16), and one MAb is directed to major capsid protein VP2 (MAb 860-55D). Two MAbs, 1418-1 and 1418-16, which were generated from the same individual have identity in the cDNA sequences encoding the variable domains, with the exception of four base pairs resulting in only one amino acid change in the light chain. The NS1- and VP1-specific MAbs interact with linear epitopes, whereas the recognized epitope in VP2 is conformational. The MAbs specific for the structural proteins display strong virus-neutralizing activity. The VP1- and VP2-specific MAbs have the capacity to neutralize 50% of infectious parvovirus B19 in vitro at 0.08 and 0.73 μg/ml, respectively, demonstrating the importance of such antibodies in the clearance of B19 viremia. The NS1-specific MAb mediated weak neutralizing activity and required 47.7 μg/ml for 50% neutralization. The human MAbs with potent neutralizing activity could be used for immunotherapy of chronically B19 virus-infected individuals and acutely infected pregnant women. Furthermore, the knowledge gained regarding epitopes which induce strongly neutralizing antibodies may be important for vaccine development.

scholarly journals An Exposed Domain in the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Induces Neutralizing Antibodies

2004 ◽  
Vol 78 (13) ◽  
pp. 7217-7226 ◽  
Author(s):  
Tong Zhou ◽  
Hong Wang ◽  
Danlin Luo ◽  
Thomas Rowe ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vero Cells ◽  
Spike Protein ◽  
Protein Fragment

ABSTRACT Exposed epitopes of the spike protein may be recognized by neutralizing antibodies against severe acute respiratory syndrome (SARS) coronavirus (CoV). A protein fragment (S-II) containing predicted epitopes of the spike protein was expressed in Escherichia coli. The properly refolded protein fragment specifically bound to the surface of Vero cells. Monoclonal antibodies raised against this fragment recognized the native spike protein of SARS CoV in both monomeric and trimeric forms. These monoclonal antibodies were capable of blocking S-II attachment to Vero cells and exhibited in vitro antiviral activity. These neutralizing antibodies mapped to epitopes in two peptides, each comprising 20 amino acids. Thus, this region of the spike protein might be a target for generation of therapeutic neutralizing antibodies against SARS CoV and for vaccine development to elicit protective humoral immunity.

scholarly journals Effects of Size and Surface Properties of Nanodiamonds on the Immunogenicity of Plant-Based H5 Protein of A/H5N1 Virus in Mice

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1597
Author(s):  
Thuong Thi Ho ◽  
Van Thi Pham ◽  
Tra Thi Nguyen ◽  
Vy Thai Trinh ◽  
Tram Vi ◽  
...  
Keyword(s):  
High Pressure ◽  
Neutralizing Antibodies ◽  
H5n1 Virus ◽  
Vaccine Development ◽  
Particle Characterization ◽  
Innovative Strategy ◽  
Specific Igg ◽  
Positively Charged

Nanodiamond (ND) has recently emerged as a potential nanomaterial for nanovaccine development. Here, a plant-based haemagglutinin protein (H5.c2) of A/H5N1 virus was conjugated with detonation NDs (DND) of 3.7 nm in diameter (ND4), and high-pressure and high-temperature (HPHT) oxidative NDs of ~40–70 nm (ND40) and ~100–250 nm (ND100) in diameter. Our results revealed that the surface charge, but not the size of NDs, is crucial to the protein conjugation, as well as the in vitro and in vivo behaviors of H5.c2:ND conjugates. Positively charged ND4 does not effectively form stable conjugates with H5.c2, and has no impact on the immunogenicity of the protein both in vitro and in vivo. In contrast, the negatively oxidized NDs (ND40 and ND100) are excellent protein antigen carriers. When compared to free H5.c2, H5.c2:ND40, and H5.c2:ND100 conjugates are highly immunogenic with hemagglutination titers that are both 16 times higher than that of the free H5.c2 protein. Notably, H5.c2:ND40 and H5.c2:ND100 conjugates induce over 3-folds stronger production of both H5.c2-specific-IgG and neutralizing antibodies against A/H5N1 than free H5.c2 in mice. These findings support the innovative strategy of using negatively oxidized ND particles as novel antigen carriers for vaccine development, while also highlighting the importance of particle characterization before use.

scholarly journals The Impact on Infectivity and Neutralization Efficiency of SARS-CoV-2 Lineage B.1.351 Pseudovirus

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 633
Author(s):  
Yeong Jun Kim ◽  
Ui Soon Jang ◽  
Sandrine M. Soh ◽  
Joo-Youn Lee ◽  
Hye-Ra Lee
Keyword(s):  
South Africa ◽  
Monoclonal Antibodies ◽  
Cell Fusion ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Receptor Binding Domain ◽  
Viral Spread ◽  
New Variant ◽  
Global Concern ◽  
The Impact

A new variant of SARS-CoV-2 B.1.351 lineage (first found in South Africa) has been raising global concern due to its harboring of multiple mutations in the spike that potentially increase transmissibility and yield resistance to neutralizing antibodies. We here tested infectivity and neutralization efficiency of SARS-CoV-2 spike pseudoviruses bearing particular mutations of the receptor-binding domain (RBD) derived either from the Wuhan strains (referred to as D614G or with other sites) or the B.1.351 lineage (referred to as N501Y, K417N, and E484K). The three different pseudoviruses B.1.351 lineage related significantly increased infectivity compared with other mutants that indicated Wuhan strains. Interestingly, K417N and E484K mutations dramatically enhanced cell–cell fusion than N501Y even though their infectivity were similar, suggesting that K417N and E484K mutations harboring SARS-CoV-2 variant might be more transmissible than N501Y mutation containing SARS-CoV-2 variant. We also investigated the efficacy of two different monoclonal antibodies, Casirivimab and Imdevimab that neutralized SARS-CoV-2, against several kinds of pseudoviruses which indicated Wuhan or B.1.351 lineage. Remarkably, Imdevimab effectively neutralized B.1.351 lineage pseudoviruses containing N501Y, K417N, and E484K mutations, while Casirivimab partially affected them. Overall, our results underscore the importance of B.1.351 lineage SARS-CoV-2 in the viral spread and its implication for antibody efficacy.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

Chimeric virus-like particles of universal antigen epitopes of coronavirus and phage Qβ coat protein trigger the production of neutralizing antibodies

2021 ◽  
Vol 21 ◽  
Author(s):  
Yukun Guo ◽  
Ruizhen Guo ◽  
Yingxian Ma ◽  
Wenru Chang ◽  
Shengli Ming ◽  
...  
Keyword(s):  
Coat Protein ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Genetic Recombination ◽  
Fluorescent Label ◽  
Salting Out ◽  
Virus Like Particles ◽  
Chimeric Vlps ◽  
Universal Epitope

Background: Virus-like particles (VLPs) are non-genetic multimeric nanoparticles synthesized through in vitro or in vivo self-assembly of one or more viral structural proteins. Immunogenicity and safety of VLPs make them ideal candidates for vaccine development and efficient nanocarriers for foreign antigens or adjuvants to activate the immune system. Aims: The present study aimed to design and synthesize a chimeric VLP vaccine of the phage Qbeta (Qβ) coat protein presenting the universal epitope of the coronavirus. Methods: The RNA phage Qβ coat protein was designed and synthesized, denoted as Qbeta. The CoV epitope, a universal epitope of coronavirus, was inserted into the C-terminal of Qbeta using genetic recombination, which was designated as Qbeta-CoV. The N-terminal of Qbeta-CoV was successively inserted into the TEV restriction site using mCherry red fluorescent label and modified affinity-purified histidine label 6xHE, which was denoted as HE-Qbeta-CoV. Isopropyl β-D-1-thiogalactopyranoside (IPTG) assessment revealed the expression of Qbeta, Qbeta-CoV, and HE-Qbeta-CoV in the BL21 (DE3) cells. The fusion protein was purified by salting out using ammonium sulfate and affinity chromatography. The morphology of particles was observed using electron microscopy. The female BALB/C mice were immunized intraperitoneally with the Qbeta-CoV and HE-Qbeta-CoV chimeric VLPs vaccines. Their sera were collected for the detection of antibody level and antibody titer using ELISA. The serum is used for the neutralization test of the three viruses of MHV, PEDV, and PDCoV. Results: The results revealed that the fusion proteins Qbeta, Qbeta-CoV, and HE-Qbeta-CoV could all obtain successful expression. Particles with high purity were obtained after purification; the chimeric particles of Qbeta-CoV and HE-Qbeta-CoV were found to be similar to Qbeta particles in morphology and formed chimeric VLPs. In addition, two chimeric VLP vaccines induced specific antibody responses in mice, and the antibodies showed certain neutralizing activity. Conclusion: The successful construction of the chimeric VLPs of the phage Qβ coat protein presenting the universal epitope of coronavirus provides a vaccine form with potential clinical applications for the treatment of coronavirus disease.

scholarly journals Antigenic Drift of the Influenza A(H1N1)pdm09 Virus Neuraminidase Results in Reduced Effectiveness of A/California/7/2009 (H1N1pdm09)-Specific Antibodies

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Jin Gao ◽  
Laura Couzens ◽  
David F. Burke ◽  
Hongquan Wan ◽  
Patrick Wilson ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
Influenza Vaccines ◽  
Vaccine Production ◽  
Antigenic Sites ◽  
Vaccine Component ◽  
Influenza A H1n1 ◽  
The Impact

ABSTRACTThe effectiveness of influenza vaccines against circulating A(H1N1)pdm09 viruses was modest for several seasons despite the absence of antigenic drift of hemagglutinin (HA), the primary vaccine component. Since antibodies against HA and neuraminidase (NA) contribute independently to protection against disease, antigenic changes in NA may allow A(H1N1)pdm09 viruses to escape from vaccine-induced immunity. In this study, analysis of the specificities of human NA-specific monoclonal antibodies identified antigenic sites that have changed over time. The impact of these differences onin vitroinhibition of enzyme activity was not evident for polyclonal antisera until viruses emerged in 2013 without a predicted glycosylation site at amino acid 386 in NA. Phylogenetic and antigenic cartography demonstrated significant antigenic changes that in most cases aligned with genetic differences. Typical of NA drift, the antigenic difference is observed in one direction, with antibodies against conserved antigenic domains in A/California/7/2009 (CA/09) continuing to inhibit NA of recent A(H1N1)pdm09 viruses reasonably well. However, ferret CA/09-specific antiserum that inhibited the NA of A/Michigan/45/2015 (MI/15) very wellin vitro, protected mice against lethal MI/15 infection poorly. These data show that antiserum against the homologous antigen is most effective and suggest the antigenic properties of NA should not be overlooked when selecting viruses for vaccine production.IMPORTANCEThe effectiveness of seasonal influenza vaccines against circulating A(H1N1)pdm09 viruses has been modest in recent years, despite the absence of antigenic drift of HA, the primary vaccine component. Human monoclonal antibodies identified antigenic sites in NA that changed early after the new pandemic virus emerged. The reactivity of ferret antisera demonstrated antigenic drift of A(H1N1)pdm09 NA from 2013 onward. Passive transfer of serum raised against A/California/7/2009 was less effective than ferret serum against the homologous virus in protecting mice against a virus with the NA of more recent virus, A/Michigan/45/2015. Given the long-standing observation that NA-inhibiting antibodies are associated with resistance against disease in humans, these data demonstrate the importance of evaluating NA drift and suggest that vaccine effectiveness might be improved by selecting viruses for vaccine production that have NAs antigenically similar to those of circulating influenza viruses.

scholarly journals Bovine Babesiosis in Turkey: Impact, Current Gaps, and Opportunities for Intervention

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1041
Author(s):  
Sezayi Ozubek ◽  
Reginaldo G. Bastos ◽  
Heba F. Alzan ◽  
Abdullah Inci ◽  
Munir Aktas ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Point Of Care ◽  
Animal Health ◽  
Current Control ◽  
Diagnostic Methods ◽  
Control Measures ◽  
Bovine Babesiosis ◽  
Research Programs ◽  
The Impact

Bovine babesiosis is a global tick-borne disease that causes important cattle losses and has potential zoonotic implications. The impact of bovine babesiosis in Turkey remains poorly characterized, but several Babesia spp., including B. bovis, B. bigemina, and B. divergens, among others and competent tick vectors, except Rhipicephalus microplus, have been recently identified in the country. Bovine babesiosis has been reported in all provinces but is more prevalent in central and highly humid areas in low and medium altitude regions of the country housing approximately 70% of the cattle population. Current control measures include acaricides and babesicidal drugs, but not live vaccines. Despite the perceived relevant impact of bovine babesiosis in Turkey, basic research programs focused on developing in vitro cultures of parasites, point-of-care diagnostic methods, vaccine development, “omics” analysis, and gene manipulation techniques of local Babesia strains are scarce. Additionally, no effective and coordinated control efforts managed by a central animal health authority have been established to date. Development of state-of-the-art research programs in bovine babesiosis to address current gaps in knowledge and implementation of long-term plans to control the disease will surely result in important economic, nutritional, and public health benefits for the country and the region.

scholarly journals Immunogenicity and Cross-Reactivity of Rhesus Adenoviral Vectors

2018 ◽  
Vol 92 (11) ◽  
Author(s):  
M. Justin Iampietro ◽  
Rafael A. Larocca ◽  
Nicholas M. Provine ◽  
Peter Abbink ◽  
Zi Han Kang ◽  
...  
Keyword(s):  
T Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
T Cell Responses ◽  
Adenoviral Vectors ◽  
Cross Reactivity ◽  
Human Populations ◽  
Humoral Immune ◽  
Cell Responses ◽  
The Impact

ABSTRACT Adenovirus (Ad) vectors are being investigated as vaccine candidates, but baseline antivector immunity exists in human populations to both human Ad (HuAd) and chimpanzee Ad (ChAd) vectors. In this study, we investigated the immunogenicity and cross-reactivity of a panel of recently described rhesus adenoviral (RhAd) vectors. RhAd vectors elicited T cells with low exhaustion markers and robust anamnestic potential. Moreover, RhAd vector immunogenicity was unaffected by high levels of preexisting anti-HuAd immunity. Both HuAd/RhAd and RhAd/RhAd prime-boost vaccine regimens were highly immunogenic, despite a degree of cross-reactive neutralizing antibodies (NAbs) between phylogenetically related RhAd vectors. We observed extensive vector-specific cross-reactive CD4 T cell responses and more limited CD8 T cell responses between RhAd and HuAd vectors, but the impact of vector-specific cellular responses was far less than that of vector-specific NAbs. These data suggest the potential utility of RhAd vectors and define novel heterologous prime-boost strategies for vaccine development. IMPORTANCE To date, most adenoviral vectors developed for vaccination have been HuAds from species B, C, D, and E, and human populations display moderate to high levels of preexisting immunity. There is a clinical need for new adenoviral vectors that are not hindered by preexisting immunity. Moreover, the development of RhAd vector vaccines expands our ability to vaccinate against multiple pathogens in a population that may have received other HuAd or ChAd vectors. We evaluated the immunogenicity and cross-reactivity of RhAd vectors, which belong to the poorly described adenovirus species G. These vectors induced robust cellular and humoral immune responses and were not hampered by preexisting anti-HuAd vector immunity. Such properties make RhAd vectors attractive as potential vaccine vectors.

scholarly journals Monoclonal Antibodies to Shigella Lipopolysaccharide Are Useful for Vaccine Production

2016 ◽  
Vol 23 (8) ◽  
pp. 681-688 ◽  
Author(s):  
Jisheng Lin ◽  
Mark A. Smith ◽  
William H. Benjamin ◽  
Robert W. Kaminski ◽  
Heather Wenzel ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Vaccine Development ◽  
Shigella Flexneri ◽  
High Sensitivity ◽  
Epidemiological Data ◽  
Enzyme Linked Immunosorbent Assay ◽  
Content Type ◽  
Bacterial Surface ◽  
Bactericidal Assay

ABSTRACTThere is a significant need for an effective multivalentShigellavaccine that targets the most prevalent serotypes. MostShigellavaccines under development utilize serotype-specific lipopolysaccharides (LPSs) as a major component based on protection and epidemiological data. As vaccine formulations advance from monovalent to multivalent, assays and reagents need to be developed to accurately and reproducibly quantitate the amount of LPSs from multiple serotypes in the final product. To facilitate this effort, we produced 36 hybridomas that secrete monoclonal antibodies (MAbs) against the O antigen on the LPS fromShigella flexneri2a,Shigella flexneri3a, andShigella sonnei. We used six of these monoclonal antibodies for an inhibition enzyme-linked immunosorbent assay (iELISA), measuring LPSs with high sensitivity and specificity. It was also demonstrated that theShigellaserotype-specific MAbs were useful for bacterial surface staining detected by flow cytometry. These MAbs are also useful for standardizing the serum bactericidal assay (SBA) forShigella. Functional assays, such as thein vitrobactericidal assay, are necessary for vaccine evaluation and may serve as immunological correlates of immunity. AnS. flexneri2a-specific monoclonal antibody killedS. flexneri2b isolates, suggesting thatS. flexneri2a LPS may induce cross-protection againstS. flexneri2b. Overall, theShigellaLPS-specific MAbs described have potential utility to the vaccine development community for assessing multivalent vaccine composition and as a reliable control for multiple immunoassays used to assess vaccine potency.

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