scholarly journals Evolution of Early SARS-CoV-2 and Cross-Coronavirus Immunity

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Carolin Loos ◽  
Caroline Atyeo ◽  
Stephanie Fischinger ◽  
John Burke ◽  
Matthew D. Slein ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Humoral Immunity ◽  
Severe Disease ◽  
Binding Domain ◽  
The Novel ◽  
Receptor Binding Domain ◽  
Functional Evolution ◽  
Evolution Of Immunity ◽  
Induced Immunity

ABSTRACT The novel coronavirus, SARS-coronavirus (CoV)-2 (SARS-CoV-2), has caused over 17 million infections in just a few months, with disease manifestations ranging from largely asymptomatic infection to critically severe disease. The remarkable spread and unpredictable disease outcomes continue to challenge management of this infection. Among the hypotheses to explain the heterogeneity of symptoms is the possibility that exposure to other coronaviruses (CoVs), or overall higher capability to develop immunity against respiratory pathogens, may influence the evolution of immunity to SARS-CoV-2. Thus, we profiled the immune response across multiple coronavirus receptor binding domains (RBDs), respiratory viruses, and SARS-CoV-2, to determine whether heterologous immunity to other CoV-RBDs or other infections influenced the evolution of the SARS-CoV-2 humoral immune response. Overall changes in subclass, isotype, and Fc-receptor binding were profiled broadly across a cohort of 43 individuals against different coronaviruses—RBDs of SARS-CoV-2 and the more common HKU1 and NL63 viruses. We found rapid functional evolution of responses to SARS-CoV-2 over time, along with broad but relatively more time-invariant responses to the more common CoVs. Moreover, there was little evidence of correlation between SARS-CoV-2 responses and HKU1, NL63, and respiratory infection (influenza and respiratory syncytial virus) responses. These findings suggest that common viral infections including common CoV immunity, targeting the receptor binding domain involved in viral infection, do not appear to influence the rapid functional evolution of SARS-CoV-2 immunity, and thus should not impact diagnostics or shape vaccine-induced immunity. IMPORTANCE A critical step to ending the spread of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the ability to detect, diagnose, and understand why some individuals develop mild and others develop severe disease. For example, defining the early evolutionary patterns of humoral immunity to SARS-CoV-2, and whether prevalent coronaviruses or other common infections influence the evolution of immunity, remains poorly understood but could inform diagnostic and vaccine development. Here, we deeply profiled the evolution of SARS-CoV-2 immunity, and how it is influenced by other coinfections. Our data suggest an early and rapid rise in functional humoral immunity in the first 2 weeks of infection across antigen-specific targets, which is negligibly influenced by cross-reactivity to additional common coronaviruses or common respiratory infections. These data suggest that preexisting receptor binding domain-specific immunity does not influence or bias the evolution of immunity to SARS-CoV-2 and should have negligible influence on shaping diagnostic or vaccine-induced immunity.

scholarly journals Engineered ACE2 counteracts vaccine-evading SARS-CoV-2 Omicron variant

2021 ◽  
Author(s):  
Nariko Ikemura ◽  
Shunta Taminishi ◽  
Tohru Inaba ◽  
Takao Arimori ◽  
Daisuke Motooka ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Mutational Analysis ◽  
High Sensitivity ◽  
Binding Domain ◽  
Spike Protein ◽  
The Novel ◽  
Receptor Binding Domain ◽  
Therapeutic Drugs ◽  
Viral Mutation ◽  
Therapeutic Value

The novel SARS-CoV-2 variant, Omicron (B.1.1.529) contains an unusually high number of mutations (>30) in the spike protein, raising concerns of escape from vaccines, convalescent sera and therapeutic drugs. Here we analyze the alteration of neutralizing titer with Omicron pseudovirus. Sera of 3 months after double BNT162b2 vaccination exhibit approximately 18-fold lower neutralization titers against Omicron. Convalescent sera from Alpha and Delta patients allow similar levels of breakthrough by Omicron. However, some Delta patients have relatively preserved neutralization efficacy, comparable to 3-month double BNT162b2 vaccination. Domain-wise analysis using chimeric spike revealed that this efficient evasion was, at least in part, caused by multiple mutations in the N-terminal domain. Omicron escapes the therapeutic cocktail of imdevimab and casirivimab, whereas sotrovimab, which targets a conserved region to avoid viral mutation, remains effective against Omicron. The ACE2 decoy is another virus-neutralizing drug modality that is free, at least in theory, from mutational escape. Deep mutational analysis demonstrated that, indeed, the engineered ACE2 overcomes every single-residue mutation in the receptor-binding domain, similar to immunized sera. Like previous SARS-CoV-2 variants, Omicron and some other sarbecoviruses showed high sensitivity against engineered ACE2, confirming the therapeutic value against diverse variants, including those that are yet to emerge.

scholarly journals The spike protein of SARS-CoV-2 induces endothelial inflammation through integrin α5β1 and NF-κB

2021 ◽  
Author(s):  
Juan Pablo Robles ◽  
Magdalena Zamora ◽  
Gonzalo Martinez de la Escalera ◽  
Carmen Clapp
Keyword(s):  
Receptor Binding ◽  
Nuclear Translocation ◽  
Umbilical Vein ◽  
Vascular Inflammation ◽  
Severe Disease ◽  
Binding Domain ◽  
Spike Protein ◽  
Whole Body ◽  
Receptor Binding Domain ◽  
Integrin Α5β1

Vascular endothelial cells (EC) form a critical interface between blood and tissues that maintains whole-body homeostasis. In COVID-19, disruption of the EC barrier results in edema, vascular inflammation, and coagulation, the hallmarks of the severe disease. However, the mechanisms by which EC are dysregulated in COVID-19 are unclear. Here, we show that the spike protein of SARS-CoV-2 alone activates the EC inflammatory phenotype in a manner dependent on integrin α5β1 signaling. Incubation of human umbilical vein EC with whole spike, its receptor-binding domain, or the integrin-binding tripeptide RGD induced the nuclear translocation of NF-κB and enhanced the expression of leukocyte adhesion molecules VCAM1 and ICAM1, the adhesion of peripheral blood leukocytes, and the permeability of the monolayer. Inhibitors of integrin α5β1 activation prevented these effects. We suggest that the spike protein, through its RGD motif in the receptor-binding domain, binds to integrin α5β1 in EC to activate Rho GTPases, eNOS pathways, and the NF-κB gene expression program responsible for vascular leakage and leukocyte infiltration, respectively. These findings uncover a new direct action of SARS-CoV-2 on EC dysfunction and introduce integrin α5β1 as a promising target for treating vascular inflammation in COVID-19.

scholarly journals Recombinant Mycobacterium paragordonae Expressing SARS-CoV-2 Receptor-Binding Domain as a Vaccine Candidate Against SARS-CoV-2 Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Byoung-Jun Kim ◽  
Hyein Jeong ◽  
Hyejun Seo ◽  
Mi-Hyun Lee ◽  
Hyun Mu Shin ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Immune Responses ◽  
Receptor Binding ◽  
Humoral Immune Response ◽  
Vaccine Candidate ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Live Virus ◽  
Humoral Immune

At present, concerns that the recent global emergence of SARS-CoV-2 variants could compromise the current vaccines have been raised, highlighting the urgent demand for new vaccines capable of eliciting T cell-mediated immune responses, as well as B cell-mediated neutralizing antibody production. In this study, we developed a novel recombinant Mycobacterium paragordonae expressing the SARS-CoV-2 receptor-binding domain (RBD) (rMpg-RBD-7) that is capable of eliciting RBD-specific immune responses in vaccinated mice. The potential use of rMpg-RBD-7 as a vaccine for SARS-CoV-2 infections was evaluated in in vivo using mouse models of two different modules, one for single-dose vaccination and the other for two-dose vaccination. In a single-dose vaccination model, we found that rMpg-RBD-7 versus a heat-killed strain could exert an enhanced cell-mediated immune (CMI) response, as well as a humoral immune response capable of neutralizing the RBD and ACE2 interaction. In a two-dose vaccination model, rMpg-RBD-7 in a two-dose vaccination could also exert a stronger CMI and humoral immune response to neutralize SARS-CoV-2 infections in pseudoviral or live virus infection systems, compared to single dose vaccinations of rMpg-RBD or two-dose RBD protein immunization. In conclusion, our data showed that rMpg-RBD-7 can lead to an enhanced CMI response and humoral immune responses in mice vaccinated with both single- or two-dose vaccination, highlighting its feasibility as a novel vaccine candidate for SARS-CoV-2. To the best of our knowledge, this study is the first in which mycobacteria is used as a delivery system for a SARS-CoV-2 vaccine.

scholarly journals A Structural Landscape of Neutralizing Antibodies Against SARS-CoV-2 Receptor Binding Domain

2021 ◽  
Vol 12 ◽  
Author(s):  
Ling Niu ◽  
Kathryn N. Wittrock ◽  
Gage C. Clabaugh ◽  
Vikram Srivastava ◽  
Michael W. Cho
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Critical Role ◽  
Binding Domain ◽  
The Novel ◽  
Receptor Binding Domain ◽  
Correlates Of Protection ◽  
Immune Correlates ◽  
Virus Life Cycle ◽  
Novel Coronavirus

SARS-CoV-2, the novel coronavirus responsible for the ongoing COVID-19 pandemic, has been spreading rampantly. The global scientific community has responded rapidly to understand immune correlates of protection to develop vaccines and immunotherapeutics against the virus. The major goal of this mini review is to summarize current understanding of the structural landscape of neutralizing antibodies (nAbs) that target the receptor binding domain (RBD) of viral spike (S) glycoprotein. The RBD plays a critical role in the very first step of the virus life cycle. Better understanding of where and how nAbs bind the RBD should enable identification of sites of vulnerability and facilitate better vaccine design and formulation of immunotherapeutics. Towards this goal, we compiled 38 RBD-binding nAbs with known structures. Review of these nAb structures showed that (1) nAbs can be divided into five general clusters, (2) there are distinct non-neutralizing faces on the RBD, and (3) maximum of potentially four nAbs could bind the RBD simultaneously. Since most of these nAbs were isolated from virus-infected patients, additional analyses of vaccine-induced nAbs could facilitate development of improved vaccines.

Antiviral Drug Design Based on the Opening Mechanism of Spike Glycoprotein in SARS-CoV-2

2021 ◽  
Author(s):  
Ruichao Mao ◽  
Lihua Bie ◽  
Maofeng Xu ◽  
Xiaocong Wang ◽  
Jun Gao
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Drug Design ◽  
Host Cell ◽  
Receptor Binding ◽  
Antiviral Drug ◽  
Binding Domain ◽  
The Novel ◽  
Receptor Binding Domain ◽  
Spike Glycoprotein

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the host cell after the receptor binding domain (RBD) of the virus spike (S) glycoprotein binding to the human angiotensin-converting...

scholarly journals Immunogenicity Studies of Plant-Produced SARS-CoV-2 Receptor Binding Domain-Based Subunit Vaccine Candidate with Different Adjuvant Formulations

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 744
Author(s):  
Konlavat Siriwattananon ◽  
Suwimon Manopwisedjaroen ◽  
Balamurugan Shanmugaraj ◽  
Eakachai Prompetchara ◽  
Chutitorn Ketloy ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Lipid A ◽  
Binding Domain ◽  
Poly I:C ◽  
Receptor Binding Domain ◽  
Monophosphoryl Lipid A ◽  
Polycytidylic Acid ◽  
Significant Difference

Due to the rapid transmission of the coronavirus disease 2019 (COVID-19) causing serious public health problems and economic burden, the development of effective vaccines is a high priority for controlling the virus spread. Our group has previously demonstrated that the plant-produced receptor-binding domain (RBD) of SARS-CoV-2 fused with Fc of human IgG was capable of eliciting potent neutralizing antibody and cellular immune responses in animal studies, and the immunogenicity could be improved by the addition of an alum adjuvant. Here, we performed a head-to-head comparison of different commercially available adjuvants, including aluminum hydroxide gel (alum), AddaVax (MF59), monophosphoryl lipid A from Salmonella minnesota R595 (mPLA-SM), and polyinosinic-polycytidylic acid (poly(I:C)), in mice by combining them with plant-produced RBD-Fc, and the differences in the immunogenicity of RBD-Fc with different adjuvants were evaluated. The specific antibody responses in terms of total IgG, IgG1, and IgG2a subtypes and neutralizing antibodies, as well as vaccine-specific T-lymphocyte responses, induced by the different tested adjuvants were compared. We observed that all adjuvants tested here induced a high level of total IgG and neutralizing antibodies, but mPLA-SM and poly (I:C) showed the induction of a balanced IgG1 and IgG2a (Th2/Th1) immune response. Further, poly (I:C) significantly increased the frequency of IFN-γ-expressing cells compared with control, whereas no significant difference was observed between the adjuvanted groups. This data revealed the adjuvants’ role in enhancing the immune response of RBD-Fc vaccination and the immune profiles elicited by different adjuvants, which could prove helpful for the rational development of next-generation SARS-CoV-2 RBD-Fc subunit vaccines. However, additional research is essential to further investigate the efficacy and safety of this vaccine formulation before clinical trials.

scholarly journals Comparative Immunomodulatory Evaluation of the Receptor Binding Domain of the SARS-CoV-2 Spike Protein; a Potential Vaccine Candidate Which Imparts Potent Humoral and Th1 Type Immune Response in a Mouse Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Tripti Shrivastava ◽  
Balwant Singh ◽  
Zaigham Abbas Rizvi ◽  
Rohit Verma ◽  
Sandeep Goswami ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Unmet Need ◽  
Binding Domain ◽  
Spike Protein ◽  
Cell Immune Response ◽  
Receptor Binding Domain

The newly emerged novel coronavirus, SARS-CoV-2, the causative agent of COVID-19 has proven to be a threat to the human race globally, thus, vaccine development against SARS-CoV-2 is an unmet need driving mass vaccination efforts. The receptor binding domain of the spike protein of this coronavirus has multiple neutralizing epitopes and is associated with viral entry. Here we have designed and characterized the SARS-CoV-2 spike protein fragment 330-526 as receptor binding domain 330-526 (RBD330-526) with two native glycosylation sites (N331 and N343); as a potential subunit vaccine candidate. We initially characterized RBD330-526 biochemically and investigated its thermal stability, humoral and T cell immune response of various RBD protein formulations (with or without adjuvant) to evaluate the inherent immunogenicity and immunomodulatory effect. Our result showed that the purified RBD immunogen is stable up to 72 h, without any apparent loss in affinity or specificity of interaction with the ACE2 receptor. Upon immunization in mice, RBD generates a high titer humoral response, elevated IFN-γ producing CD4+ cells, cytotoxic T cells, and robust neutralizing antibodies against live SARS-CoV-2 virus. Our results collectively support the potential of RBD330-526 as a promising vaccine candidate against SARS-CoV-2.

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