Coronaviruses make use of a large envelope protein called spike (S) to engage host cell receptors and catalyze membrane fusion. Because of the vital role that these S proteins play, they represent a ...vulnerable target for the development of therapeutics. Here, we describe the isolation of single-domain antibodies (VHHs) from a llama immunized with prefusion-stabilized coronavirus spikes. These VHHs neutralize MERS-CoV or SARS-CoV-1 S pseudotyped viruses, respectively. Crystal structures of these VHHs bound to their respective viral targets reveal two distinct epitopes, but both VHHs interfere with receptor binding. We also show cross-reactivity between the SARS-CoV-1 S-directed VHH and SARS-CoV-2 S and demonstrate that this cross-reactive VHH neutralizes SARS-CoV-2 S pseudotyped viruses as a bivalent human IgG Fc-fusion. These data provide a molecular basis for the neutralization of pathogenic betacoronaviruses by VHHs and suggest that these molecules may serve as useful therapeutics during coronavirus outbreaks.
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•VHHs isolated from a llama immunized with prefusion-stabilized coronavirus spikes•Structural characterization of VHHs reveals conserved mechanism of neutralization•SARS-CoV-1 S-directed VHH cross-reacts with SARS-CoV-2 S•Bivalent VHH neutralizes SARS-CoV-2 pseudoviruses
Using llamas immunized with prefusion-stabilized betacoronavirus spike proteins, Wrapp et al. identify neutralizing cross-reactive single-domain camelid antibodies, which may serve not only as useful reagents for researchers studying the viruses causing MERS, SARS, and COVID-19, but also potential therapeutic candidates. Crystal structures further reveal how these antibodies bind spike proteins to prevent virus entry into cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 as a highly transmissible pathogenic human betacoronavirus. The viral spike glycoprotein (S) utilizes angiotensin-converting ...enzyme 2 (ACE2) as a host protein receptor and mediates fusion of the viral and host membranes, making S essential to viral entry into host cells and host species tropism. As SARS-CoV enters host cells, the viral S is believed to undergo a number of conformational transitions as it is cleaved by host proteases and binds to host receptors. We recently developed stabilizing mutations for coronavirus spikes that prevent the transition from the pre-fusion to post-fusion states. Here, we present cryo-EM analyses of a stabilized trimeric SARS-CoV S, as well as the trypsin-cleaved, stabilized S, and its interactions with ACE2. Neither binding to ACE2 nor cleavage by trypsin at the S1/S2 cleavage site impart large conformational changes within stabilized SARS-CoV S or expose the secondary cleavage site, S2'.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
I am honored to receive the E. E. Just Award. I applaud ASCB's commitment to recognizing the contributions of researchers from historically excluded racial and ethnic groups and appreciate my ...inclusion on a long list of accomplished peers. I also thank Barney Graham, who not only had a profound impact on my own career, but has a deep commitment to advancing unrepresented groups in the sciences. Finally, I thank my parents, for encouraging me to use my scholarship to excite change, for reminding me that anything is possible, and for advising me with tenderness along the way. As I recently went through a career transition, I found myself returning to much of my father's sage advice. In this essay, I discuss one important piece of advice that I received from my father in hopes that it will help others navigate their own career choices.
How well do serum samples from persons vaccinated with the mRNA-1273 vaccine neutralize the P.1 lineage, the B.1.1.7 lineage, the B.1.1.7 lineage plus the E484K mutation, the B.1.351 lineage, and the ...B.1.427/B.1.429 lineage of SARS-CoV-2? This study provides an answer.
Five Lessons of Resilience in Science Corbett-Helaire, Kizzmekia S
The Journal of infectious diseases,
2024-May-15, 2024-05-15, 20240515, Volume:
229, Issue:
5
Journal Article
Middle East respiratory syndrome coronavirus (MERS-CoV) is a lineage C betacoronavirus that since its emergence in 2012 has caused outbreaks in human populations with case-fatality rates of ∼36%. As ...in other coronaviruses, the spike (S) glycoprotein of MERS-CoV mediates receptor recognition and membrane fusion and is the primary target of the humoral immune response during infection. Here we use structure-based design to develop a generalizable strategy for retaining coronavirus S proteins in the antigenically optimal prefusion conformation and demonstrate that our engineered immunogen is able to elicit high neutralizing antibody titers against MERS-CoV. We also determined high-resolution structures of the trimeric MERS-CoV S ectodomain in complex with G4, a stem-directed neutralizing antibody. The structures reveal that G4 recognizes a glycosylated loop that is variable among coronaviruses and they define four conformational states of the trimer wherein each receptor-binding domain is either tightly packed at the membrane-distal apex or rotated into a receptor-accessible conformation. Our studies suggest a potential mechanism for fusion initiation through sequential receptor-binding events and provide a foundation for the structure-based design of coronavirus vaccines.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The COVID-19 pandemic of acute respiratory disease caused by SARS-CoV-2 coronavirus (CoV) is an unparalleled event that harkens back to days before viruses could be seen or understood. HIV-1 arose as ...a regional zoonotic disease during the last century and evolved into a global crisis of enormous proportions; it was nearly universally fatal, but its global spread and disease progression were relatively slow, and it was perceived as being more escapable. Uniquely, COVID-19 is caused by a newly discovered CoV strain and part of a virus family that many people had not heard of before, has substantial human-to-human transmission through respiratory secretions, has spread globally within a matter of weeks, affects individuals from all levels of society and status, and has a high enough morbidity and mortality to overwhelm our health care systems. Therefore, it has galvanized public interest in pandemic threats as no other virus has before.
HKU1 is a human betacoronavirus that causes mild yet prevalent respiratory disease, and is related to the zoonotic SARS and MERS betacoronaviruses, which have high fatality rates and pandemic ...potential. Cell tropism and host range is determined in part by the coronavirus spike (S) protein, which binds cellular receptors and mediates membrane fusion. As the largest known class I fusion protein, its size and extensive glycosylation have hindered structural studies of the full ectodomain, thus preventing a molecular understanding of its function and limiting development of effective interventions. Here we present the 4.0 Å resolution structure of the trimeric HKU1 S protein determined using single-particle cryo-electron microscopy. In the pre-fusion conformation, the receptor-binding subunits, S1, rest above the fusion-mediating subunits, S2, preventing their conformational rearrangement. Surprisingly, the S1 C-terminal domains are interdigitated and form extensive quaternary interactions that occlude surfaces known in other coronaviruses to bind protein receptors. These features, along with the location of the two protease sites known to be important for coronavirus entry, provide a structural basis to support a model of membrane fusion mediated by progressive S protein destabilization through receptor binding and proteolytic cleavage. These studies should also serve as a foundation for the structure-based design of betacoronavirus vaccine immunogens.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
An mRNA Vaccine against SARS-CoV-2 — Preliminary Report Jackson, Lisa A; Anderson, Evan J; Rouphael, Nadine G ...
New England journal of medicine/The New England journal of medicine,
11/2020, Volume:
383, Issue:
20
Journal Article
Peer reviewed
Open access
Two inoculations with a new SARS-CoV-2 mRNA-based vaccine that encodes a protein in the coronavirus spike elicited high titers of virus-neutralizing antibody in healthy adult volunteers. ...Virus-specific T-cell responses were also elicited. Interim findings indicated that a dose of 100 μg per injection maximized immune response and minimized the reactogenicity of the vaccine.
The Moderna mRNA-1273 vaccine, which elicited antibodies and T cells specific for the Covid-19 virus in adults 55 years of age or younger, elicited similarly high levels of neutralizing-antibody and ...CD4 T-cell responses in a small group of older adults, including those 71 years of age or older.
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