scholarly journals Elicitation of potent neutralizing antibody responses by designed protein nanoparticle vaccines for SARS-CoV-2

2020 ◽  
Author(s):  
Alexandra C. Walls ◽  
Brooke Fiala ◽  
Alexandra Schäfer ◽  
Samuel Wrenn ◽  
Minh N. Pham ◽  
...  
Keyword(s):  
Respiratory Disease ◽  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
High Yield ◽  
Receptor Binding Domain ◽  
Self Assembling ◽  
Human Sera ◽  
Antibody Titers ◽  
Protein Components

SUMMARYA safe, effective, and scalable vaccine is urgently needed to halt the ongoing SARS-CoV-2 pandemic. Here, we describe the structure-based design of self-assembling protein nanoparticle immunogens that elicit potent and protective antibody responses against SARS-CoV-2 in mice. The nanoparticle vaccines display 60 copies of the SARS-CoV-2 spike (S) glycoprotein receptor-binding domain (RBD) in a highly immunogenic array and induce neutralizing antibody titers roughly ten-fold higher than the prefusion-stabilized S ectodomain trimer despite a more than five-fold lower dose. Antibodies elicited by the nanoparticle immunogens target multiple distinct epitopes on the RBD, suggesting that they may not be easily susceptible to escape mutations, and exhibit a significantly lower binding:neutralizing ratio than convalescent human sera, which may minimize the risk of vaccine-associated enhanced respiratory disease. The high yield and stability of the protein components and assembled nanoparticles, especially compared to the SARS-CoV-2 prefusion-stabilized S trimer, suggest that manufacture of the nanoparticle vaccines will be highly scalable. These results highlight the utility of robust antigen display platforms for inducing potent neutralizing antibody responses and have launched cGMP manufacturing efforts to advance the lead RBD nanoparticle vaccine into the clinic.

scholarly journals A single immunization with spike-functionalized ferritin vaccines elicits neutralizing antibody responses against SARS-CoV-2 in mice

2020 ◽  
Author(s):  
Abigail E. Powell ◽  
Kaiming Zhang ◽  
Mrinmoy Sanyal ◽  
Shaogeng Tang ◽  
Payton A. Weidenbacher ◽  
...  
Keyword(s):  
Single Dose ◽  
Neutralizing Antibodies ◽  
Subunit Vaccine ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Receptor Binding Domain ◽  
Amino Acid Deletion ◽  
Vaccine Candidates ◽  
Self Assembling ◽  
Antibody Titers

AbstractDevelopment of a safe and effective SARS-CoV-2 vaccine is a public health priority. We designed subunit vaccine candidates using self-assembling ferritin nanoparticles displaying one of two multimerized SARS-CoV-2 spikes: full-length ectodomain (S-Fer) or a C-terminal 70 amino-acid deletion (SΔC-Fer). Ferritin is an attractive nanoparticle platform for production of vaccines and ferritin-based vaccines have been investigated in humans in two separate clinical trials. We confirmed proper folding and antigenicity of spike on the surface of ferritin by cryo-EM and binding to conformation-specific monoclonal antibodies. After a single immunization of mice with either of the two spike ferritin particles, a lentiviral SARS-CoV-2 pseudovirus assay revealed mean neutralizing antibody titers at least 2-fold greater than those in convalescent plasma from COVID-19 patients. Additionally, a single dose of SΔC-Fer elicited significantly higher neutralizing responses as compared to immunization with the spike receptor binding domain (RBD) monomer or spike ectodomain trimer alone. After a second dose, mice immunized with SΔC-Fer exhibited higher neutralizing titers than all other groups. Taken together, these results demonstrate that multivalent presentation of SARS-CoV-2 spike on ferritin can notably enhance elicitation of neutralizing antibodies, thus constituting a viable strategy for single-dose vaccination against COVID-19.

scholarly journals Sex Disparities and Neutralizing-Antibody Durability to SARS-CoV-2 Infection in Convalescent Individuals

mSphere ◽  
2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Alena J. Markmann ◽  
Natasa Giallourou ◽  
D. Ryan Bhowmik ◽  
Yixuan J. Hou ◽  
Aaron Lerner ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Antibody Responses ◽  
Receptor Binding Domain ◽  
Antibody Titers ◽  
Sex Disparities ◽  
Binding Antibody ◽  
Male Sex ◽  
Antibody Levels

In this study, we found that neutralizing antibody responses in COVID-19-convalescent individuals vary in magnitude but are durable and correlate well with receptor binding domain (RBD) Ig binding antibody levels compared to other SARS-CoV-2 antigen responses. In our cohort, higher neutralizing antibody titers are independently and significantly associated with male sex compared to female sex.

scholarly journals Self-assembling nanoparticles presenting receptor binding domain and stabilized spike as next-generation COVID-19 vaccines

2020 ◽  
Author(s):  
Linling He ◽  
Xiaohe Lin ◽  
Ying Wang ◽  
Ciril Abraham ◽  
Cindy Sou ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Heptad Repeat ◽  
High Yield ◽  
Receptor Binding Domain ◽  
Next Generation ◽  
Vaccine Strategy ◽  
Self Assembling ◽  
Cell Immunity

ABSTRACTWe present a comprehensive vaccine strategy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by combining antigen optimization and nanoparticle display. We first developed a receptor binding domain (RBD)-specific antibody column for purification and displayed the RBD on self-assembling protein nanoparticles (SApNPs) using the SpyTag/SpyCatcher system. We then identified the heptad repeat 2 (HR2) stalk as a major cause of spike metastability, designed an HR2-deleted glycine-capped spike (S2GΔHR2), and displayed S2GΔHR2 on three SApNPs with high yield, purity, and antigenicity. Compared to the RBD, the RBD-ferritin SApNP elicited a more potent murine neutralizing antibody (NAb) response on par with the spike. S2GΔHR2 elicited two-fold-higher NAb titers than the proline-capped spike (S2P), while S2GΔHR2 SApNPs derived from multilayered E2p and I3-01v9 60-mers elicited up to 10-fold higher NAb titers. The S2GΔHR2-presenting I3-01v9 SApNP also induced critically needed T-cell immunity, thereby providing a next-generation vaccine candidate to battle the COVID-19 pandemic.ONE-SENTENCE SUMMARYThe receptor binding domain and stabilized SARS-CoV-2 spike were displayed on nanoparticles as vaccine antigens and elicited potent immune responses.

scholarly journals Immunogenicity and structures of a rationally designed prefusion MERS-CoV spike antigen

2017 ◽  
Vol 114 (35) ◽  
pp. E7348-E7357 ◽  
Author(s):  
Jesper Pallesen ◽  
Nianshuang Wang ◽  
Kizzmekia S. Corbett ◽  
Daniel Wrapp ◽  
Robert N. Kirchdoerfer ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Case Fatality ◽  
Neutralizing Antibody ◽  
Human Populations ◽  
Receptor Binding Domain ◽  
Potential Mechanism ◽  
Primary Target ◽  
Humoral Immune ◽  
Receptor Recognition ◽  
Antibody Titers

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.

scholarly journals Reduced binding and neutralization of infection- and vaccine-induced antibodies to the B.1.351 (South African) SARS-CoV-2 variant

2021 ◽  
Author(s):  
Venkata Viswanadh Edara ◽  
Carson Norwood ◽  
Katharine Floyd ◽  
Lilin Lai ◽  
Meredith E. Davis-Gardner ◽  
...  
Keyword(s):  
South African ◽  
Receptor Binding ◽  
Symptom Onset ◽  
Protective Immunity ◽  
Neutralizing Antibody ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Live Virus ◽  
Fold Reduction ◽  
Antibody Titers

SUMMARYThe emergence of SARS-CoV-2 variants with mutations in the spike protein is raising concerns about the efficacy of infection- or vaccine-induced antibodies to neutralize these variants. We compared antibody binding and live virus neutralization of sera from naturally infected and spike mRNA vaccinated individuals against a circulating SARS-CoV-2 B.1 variant and the emerging B.1.351 variant. In acutely-infected (5-19 days post-symptom onset), convalescent COVID-19 individuals (through 8 months post-symptom onset) and mRNA-1273 vaccinated individuals (day 14 post-second dose), we observed an average 4.3-fold reduction in antibody titers to the B.1.351-derived receptor binding domain of the spike protein and an average 3.5-fold reduction in neutralizing antibody titers to the SARS-CoV-2 B.1.351 variant as compared to the B.1 variant (spike D614G). However, most acute and convalescent sera from infected and all vaccinated individuals neutralize the SARS-CoV-2 B.1.351 variant, suggesting that protective immunity is retained against COVID-19.

scholarly journals Coronavirus-Specific Antibody Cross Reactivity in Rhesus Macaques Following SARS-CoV-2 Vaccination and Infection

2021 ◽  
Author(s):  
Catherine Jacob-Dolan ◽  
Jared Feldman ◽  
Katherine McMahan ◽  
Jingyou Yu ◽  
Roland Zahn ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Specific Antibody ◽  
Rhesus Macaques ◽  
Rapid Development ◽  
Neutralizing Antibody ◽  
Cross Reactivity ◽  
Antibody Responses ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Before And After

Vaccines are being rapidly developed with the goal of ending the SARS-CoV-2 pandemic. However, the extent to which SARS-CoV-2 vaccination induces serum responses that cross-react with other coronaviruses remains poorly studied. Here we define serum profiles in rhesus macaques after vaccination with DNA or Ad26 based vaccines expressing SARS-CoV-2 Spike protein followed by SARS-CoV-2 challenge, or SARS-CoV-2 infection alone. Analysis of serum responses showed robust reactivity to the SARS-CoV-2 full-length Spike protein and receptor binding domain (RBD), both included in the vaccine. However, serum cross-reactivity to the closely related sarbecovirus SARS-CoV-1 Spike and RBD, was reduced. Reactivity was also measured to the distantly related common cold alpha-coronavirus, 229E and NL63, and beta-coronavirus, OC43 and HKU1, Spike proteins. Using SARS-COV-2 and SARS-CoV-1 lentivirus based pseudoviruses, we show that neutralizing antibody responses were predominantly SARS-CoV-2 specific. These data define patterns of cross-reactive binding and neutralizing serum responses induced by SARS-CoV-2 infection and vaccination in rhesus macaques. Our observations have important implications for understanding polyclonal responses to SARS-CoV-2 Spike, which will facilitate future CoV vaccine assessment and development. Importance The rapid development and deployment of SARS-CoV-2 vaccines has been unprecedented. In this study, we explore the cross-reactivity of SARS-CoV-2 specific antibody responses to other coronaviruses. By analyzing responses from NHPs both before and after immunization with DNA or Ad26 vectored vaccines, we find patterns of cross reactivity that mirror those induced by SARS-CoV-2 infection. These data highlight the similarities between infection and vaccine induced humoral immunity for SARS-CoV-2 and cross-reactivity of these responses to other CoVs.

scholarly journals High titers of multiple antibody isotypes against the SARS-CoV-2 spike receptor-binding domain and nucleoprotein associate with better neutralization

2020 ◽  
Author(s):  
Maria G. Noval ◽  
Maria E. Kaczmarek ◽  
Akiko Koide ◽  
Bruno A. Rodriguez-Rodriguez ◽  
Ping Louie ◽  
...  
Keyword(s):  
Antibody Response ◽  
Receptor Binding ◽  
Healthcare Workers ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Pseudotyped Virus ◽  
Receptor Binding Domain ◽  
Neutralization Capacity ◽  
Antibody Isotypes ◽  
Antibody Titers

AbstractUnderstanding antibody responses to SARS-CoV-2 is indispensable for the development of containment measures to overcome the current COVID-19 pandemic. Here, we determine the ability of sera from 101 recovered healthcare workers to neutralize both authentic SARS-CoV-2 and SARS-CoV-2 pseudotyped virus and address their antibody titers against SARS-CoV-2 nucleoprotein and spike receptor-binding domain. Interestingly, the majority of individuals have low neutralization capacity and only 6% of the healthcare workers showed high neutralizing titers against both authentic SARS-CoV-2 virus and the pseudotyped virus. We found the antibody response to SARS-CoV-2 infection generates antigen-specific isotypes as well as a diverse combination of antibody isotypes, with high titers of IgG, IgM and IgA against both antigens correlating with neutralization capacity. Importantly, we found that neutralization correlated with antibody titers as quantified by ELISA. This suggests that an ELISA assay can be used to determine seroneutralization potential. Altogether, our work provides a snapshot of the SARS-CoV-2 neutralizing antibody response in recovered healthcare workers and provides evidence that possessing multiple antibody isotypes may play an important role in SARS-CoV-2 neutralization.

scholarly journals Binding and Neutralizing Antibody Responses to SARS-CoV-2 in Infants and Young Children Exceed Those in Adults

2021 ◽  
Author(s):  
Ruth A. Karron ◽  
Maria Garcia Quesada ◽  
Elizabeth A. Schappell ◽  
Stephen D. Schmidt ◽  
Maria Deloria Knoll ◽  
...  
Keyword(s):  
Young Children ◽  
Immune Responses ◽  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Antibody Responses ◽  
Receptor Binding Domain ◽  
Binding Antibody ◽  
Infants And Young Children

SARS-CoV-2 infections are frequently milder in children than adults, suggesting that immune responses may vary with age. However, information is limited regarding SARS-CoV-2 immune responses in young children. We compared Receptor Binding Domain binding antibody (RBDAb) and SARS-CoV-2 neutralizing antibody (neutAb) in children aged 0-4 years, 5-17 years, and in adults aged 18-62 years in a SARS-CoV-2 household study. Among 55 participants seropositive at enrollment, children aged 0-4 years had >10-fold higher RBDAb titers than adults (373 vs.35, P<0.0001), and the highest RBDAb titers in 11/12 households with seropositive children and adults. Children aged 0-4 years had 2-fold higher neutAb than adults, resulting in higher binding to neutralizing (B/N)Ab ratios compared to adults (1.9 vs. 0.4 for ID50, P=0.0002). Findings suggest that young children mount robust antibody responses to SARS-CoV-2 following community infections. Additionally, these results support using neutAb to measure the immunogenicity of COVID-19 vaccines in children aged 0-4 years.

scholarly journals Twelve-month specific IgG response to SARS-CoV-2 receptor-binding domain among COVID-19 convalescent plasma donors in Wuhan

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cesheng Li ◽  
Ding Yu ◽  
Xiao Wu ◽  
Hong Liang ◽  
Zhijun Zhou ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Immune Memory ◽  
Strong Positive Correlation ◽  
Receptor Binding Domain ◽  
Igg Antibody ◽  
Humoral Immune ◽  
Positive Rate ◽  
Antibody Titers

AbstractTo investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.

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