Persistence of robust humoral immune response in COVID-19 convalescent individuals over twelve months after infection

Abstract Background SARS-CoV-2 infection elicits varying degrees of protective immunity conferred by neutralizing antibodies (nAbs). Here, we report the persistence of nAb responses over 12 months after infection despite their decreasing trend noticed from 6 months. Methods The study included sera from 497 individuals who had been infected with SARS-CoV-2 between January and August 2020. Samples were collected at 6 and 12 months after onset. The titers of IgG to the viral nucleocapsid protein (NP) and receptor-binding domain of the spike protein (RBD) were measured by CLEIA. The nAb titer was determined using lentivirus-based pseudovirus or authentic virus. Results Antibody titers of NP-IgG, RBD-IgG, and nAbs were higher in severe and moderate cases than in mild cases at 12 months after onset. While the nAb levels were likely to confer adequate protection against wild-type viral infection, the neutralization activity to recently circulating variants in some of the mild cases (~30%) was undermined, implying the susceptibility to reinfection with the variants of concerns (VOCs). Conclusions COVID-19 convalescent individuals have robust humoral immunity even at 12 months after infection albeit that the medical history and background of patients could affect the function and dynamics of antibody response to the VOCs.

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Persistence of robust humoral immune response in COVID-19 convalescent individuals over 12 months after infection

10.1101/2021.09.27.21264013 ◽

2021 ◽

Author(s):

Kei Miyakawa ◽

Sousuke Kubo ◽

Sundararaj Stanleyraj Jeremiah ◽

Hirofumi Go ◽

Yutaro Yamaoka ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Receptor Binding Domain ◽

Wild Type ◽

Virus Antibody ◽

Neutralization Activity ◽

Humoral Immune ◽

Antibody Titers ◽

Viral Nucleocapsid

SARS-CoV-2 infection elicits varying degrees of protective immunity conferred by neutralizing antibodies (nAbs). Here we report the persistence of nAb responses over 12 months after infection despite its decreasing trend noticed from 6 months. The study included sera from 358 individuals who had been infected with SARS-CoV-2 between January and May 2020. Samples were collected at 6 and 12 months after onset. The titers of IgG to the viral nucleocapsid protein (NP) and receptor-binding domain of the spike protein (RBD) were measured by CLEIA. The nAb titer was determined using lentivirus-based pseudovirus or authentic virus. Antibody titers of NP-IgG, RBD-IgG, and nAbs were higher in severe and moderate cases than in mild cases at 12 months after onset. While the nAb levels were likely to confer adequate protection against wild-type viral infection, the neutralization activity to recently circulating variants in some of the mild cases (~30%) was undermined, implying the susceptibility of reinfection to the variants of concerns (VOCs). COVID-19 convalescent individuals have robust humoral immunity even at 12 months after infection albeit that the medical history and background of patients could affect the function and dynamics of antibody response to the VOCs.

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

10.1101/2021.02.20.432046 ◽

2021 ◽

Cited By ~ 4

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.

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Decline of humoral responses against SARS-CoV-2 Spike in convalescent individuals

10.1101/2020.07.09.194639 ◽

2020 ◽

Cited By ~ 5

Author(s):

Guillaume Beaudoin-Bussières ◽

Annemarie Laumaea ◽

Sai Priya Anand ◽

Jérémie Prévost ◽

Romain Gasser ◽

...

Keyword(s):

Clinical Trials ◽

Receptor Binding ◽

Neutralizing Antibodies ◽

Receptor Binding Domain ◽

Wild Type ◽

Positive Role ◽

Neutralization Activity ◽

Specific Igg ◽

Humoral Responses ◽

Over Time

ABSTRACTIn the absence of effective vaccines and with limited therapeutic options, convalescent plasma is being collected across the globe for potential transfusion to COVID-19 patients. The therapy has been deemed safe and several clinical trials assessing its efficacy are ongoing. While it remains to be formally proven, the presence of neutralizing antibodies is thought to play a positive role in the efficacy of this treatment. Indeed, neutralizing titers of ≥1:160 have been recommended in some convalescent plasma trials for inclusion. Here we performed repeated analyses at one-month interval on 31 convalescent individuals to evaluate how the humoral responses against the SARS-CoV-2 Spike, including neutralization, evolve over time. We observed that receptor-binding domain (RBD)-specific IgG slightly decreased between six and ten weeks after symptoms onset but RBD-specific IgM decreased much more abruptly. Similarly, we observed a significant decrease in the capacity of convalescent plasma to neutralize pseudoparticles bearing SARS-CoV-2 S wild-type or its D614G variant. If neutralization activity proves to be an important factor in the clinical efficacy of convalescent plasma transfer, our results suggest that plasma from convalescent donors should be recovered rapidly after symptoms resolution.

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Decline of Humoral Responses against SARS-CoV-2 Spike in Convalescent Individuals

mBio ◽

10.1128/mbio.02590-20 ◽

2020 ◽

Vol 11 (5) ◽

Cited By ~ 14

Author(s):

Guillaume Beaudoin-Bussières ◽

Annemarie Laumaea ◽

Sai Priya Anand ◽

Jérémie Prévost ◽

Romain Gasser ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Receptor Binding Domain ◽

Wild Type ◽

Active Infection ◽

Positive Role ◽

Neutralization Activity ◽

Neutralizing Activity ◽

Specific Igg ◽

Alternative Approaches ◽

Humoral Responses

ABSTRACT In the absence of effective vaccines and with limited therapeutic options, convalescent plasma is being collected across the globe for potential transfusion to coronavirus disease 2019 (COVID-19) patients. The therapy has been deemed safe, and several clinical trials assessing its efficacy are ongoing. While it remains to be formally proven, the presence of neutralizing antibodies is thought to play a positive role in the efficacy of this treatment. Indeed, neutralizing titers of ≥1:160 have been recommended in some convalescent plasma trials for inclusion. Here, we performed repeated analyses at 1-month intervals on 31 convalescent individuals to evaluate how the humoral responses against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike glycoprotein, including neutralization, evolve over time. We observed that the levels of receptor-binding-domain (RBD)-specific IgG and IgA slightly decreased between 6 and 10 weeks after the onset of symptoms but that RBD-specific IgM levels decreased much more abruptly. Similarly, we observed a significant decrease in the capacity of convalescent plasma to neutralize pseudoparticles bearing wild-type SARS-CoV-2 S or its D614G variant. If neutralization activity proves to be an important factor in the clinical efficacy of convalescent plasma transfer, our results suggest that plasma from convalescent donors should be recovered rapidly after resolution of symptoms. IMPORTANCE While waiting for an efficient vaccine to protect against SARS-CoV-2 infection, alternative approaches to treat or prevent acute COVID-19 are urgently needed. Transfusion of convalescent plasma to treat COVID-19 patients is currently being explored; neutralizing activity in convalescent plasma is thought to play a central role in the efficacy of this treatment. Here, we observed that plasma neutralization activity decreased a few weeks after the onset of the symptoms. If neutralizing activity is required for the efficacy of convalescent plasma transfer, our results suggest that convalescent plasma should be recovered rapidly after the donor recovers from active infection.

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Receptor-Binding Domain Proteins of SARS-CoV-2 Variants Elicited Robust Antibody Responses Cross-Reacting with Wild-Type and Mutant Viruses in Mice

Vaccines ◽

10.3390/vaccines9121383 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1383

Author(s):

Juan Shi ◽

Xiaoxiao Jin ◽

Yan Ding ◽

Xiaotao Liu ◽

Anran Shen ◽

...

Keyword(s):

Receptor Binding ◽

Neutralizing Antibodies ◽

Polyclonal Antibodies ◽

Neutralizing Antibody ◽

Binding Domain ◽

Receptor Binding Domain ◽

Wild Type ◽

Neutralization Capacity ◽

Antibody Titers ◽

High Level

Multiple variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have spread around the world, but the neutralizing effects of antibodies induced by the existing vaccines have declined, which highlights the importance of developing vaccines against mutant virus strains. In this study, nine receptor-binding domain (RBD) proteins of the SARS-CoV-2 variants (B.1.1.7, B.1.351 and P.1 lineages) were constructed and fused with the Fc fragment of human IgG (RBD-Fc). These RBD-Fc proteins contained single or multiple amino acid substitutions at prevalent mutation points of spike protein, which enabled them to bind strongly to the polyclonal antibodies specific for wild-type RBD and to the recombinant human ACE2 protein. In the BALB/c, mice were immunized with the wild-type RBD-Fc protein first and boosted twice with the indicated mutant RBD-Fc proteins later. All mutant RBD-Fc proteins elicited high-level IgG antibodies and cross-neutralizing antibodies. The RBD-Fc proteins with multiple substitutions tended to induce higher antibody titers and neutralizing-antibody titers than the single-mutant RBD-Fc proteins. Meanwhile, both wild-type RBD-Fc protein and mutant RBD-Fc proteins induced significantly decreased neutralization capacity to the pseudovirus of B.1.351 and P.1 lineages than to the wild-type one. These data will facilitate the design and development of RBD-based subunit vaccines against SARS-COV-2 and its variants.

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163. Enhancing the Immunogenicity of a Novel, Low-cost Ebola Vaccine

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.473 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S211-S211

Author(s):

Samuel D Stampfer ◽

Rui Jin ◽

Chinglai Yang

Keyword(s):

Dna Vaccine ◽

Disulfide Bonds ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Cost Effective ◽

Hemorrhagic Fever ◽

Wild Type ◽

Mammalian Expression ◽

Antibody Titers

Abstract Background Ebolaviruses cause viral hemorrhagic fever with high mortality rates. Nearly all Ebola vaccines in development use Ebola glycoprotein (GP) as the immunizing antigen. GP is present on the viral membrane and functions in cell entry by binding the cellular receptor and mediating membrane fusion; antibodies to GP induce protective immunity. Ebola also produces sGP: a smaller, secreted form of GP containing the receptor-binding domain; it is also able to induce protective immunity. sGP naturally refolds after thermal denaturation and thus may be more stable than GP, and may also be more cost effective as it is produced easily in high quantities. sGP is a homodimer that is covalently linked by a cysteine near its C-terminus. In this work, we explored how modifications to sGP that affect its ability to dimerize also alter its immunogenicity. Methods sGP mutants were generated in the pCAGGS mammalian expression plasmid, and injected into mice as a DNA vaccine. Mouse sera was tested by ELISA against sGP and GP proteins, and in a neutralization assay against GP-typed pseudovirions. Results We generated 4 different mutants of sGP that had altered abilities to form inter-protomer disulfide bonds. All had a mutated or deleted cysteine at position 306; two had disulfide-bonding restored by introduction of an engineered inter-protomer disulfide bond. Mice were immunized with a DNA vaccine encoding either an sGP mutant or wild-type sGP, and sera were collected. We found that sera from sGP mutants with reduced interprotomer disulfide bonds had significantly higher antibody titers to sGP and GP than sera from our wild-type sGP and engineered-disulfide sGP immunized mice. Antibody titers were similar between sGP and GP; these titers correlated with neutralization ability. Relative binding to sGP & GP (by ELISA OD) & relative % neutralization of pseudovirions at 1:10 dilution Conclusion Immunogenicity of Ebola sGP was enhanced significantly when mutations were introduced to reduce its ability to covalently dimerize. Immunogenicity correlated with induction of neutralizing antibodies, implying that our mutants may outperform wild-type sGP when used as a vaccine in vivo. This work helps paves the way for an alternative Ebola vaccine that has the potential to be more cost-effective and heat-stable than the currently-licensed vaccine. Disclosures Samuel D. Stampfer, MD/PhD, Gilead (Shareholder)

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Selection, biophysical and structural analysis of synthetic nanobodies that effectively neutralize SARS-CoV-2

Nature Communications ◽

10.1038/s41467-020-19204-y ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Tânia F. Custódio ◽

Hrishikesh Das ◽

Daniel J. Sheward ◽

Leo Hanke ◽

Samuel Pazicky ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Spike Protein ◽

Receptor Binding Domain ◽

Combined Approach ◽

Emerging Viruses ◽

Medium Term ◽

Neutralization Activity ◽

High Affinity ◽

Isolation And Characterization

Abstract The coronavirus SARS-CoV-2 is the cause of the ongoing COVID-19 pandemic. Therapeutic neutralizing antibodies constitute a key short-to-medium term approach to tackle COVID-19. However, traditional antibody production is hampered by long development times and costly production. Here, we report the rapid isolation and characterization of nanobodies from a synthetic library, known as sybodies (Sb), that target the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. Several binders with low nanomolar affinities and efficient neutralization activity were identified of which Sb23 displayed high affinity and neutralized pseudovirus with an IC50 of 0.6 µg/ml. A cryo-EM structure of the spike bound to Sb23 showed that Sb23 binds competitively in the ACE2 binding site. Furthermore, the cryo-EM reconstruction revealed an unusual conformation of the spike where two RBDs are in the ‘up’ ACE2-binding conformation. The combined approach represents an alternative, fast workflow to select binders with neutralizing activity against newly emerging viruses.

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Selection, biophysical and structural analysis of synthetic nanobodies that effectively neutralize SARS-CoV-2

10.1101/2020.06.23.165415 ◽

2020 ◽

Cited By ~ 7

Author(s):

Tânia F. Custódio ◽

Hrishikesh Das ◽

Daniel J Sheward ◽

Leo Hanke ◽

Samuel Pazicky ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Spike Protein ◽

Receptor Binding Domain ◽

Combined Approach ◽

Emerging Viruses ◽

Medium Term ◽

Neutralization Activity ◽

High Affinity ◽

Isolation And Characterization

AbstractThe coronavirus SARS-CoV-2 is the cause of the ongoing COVID-19 pandemic. Therapeutic neutralizing antibodies constitute a key short-to-medium term approach to tackle COVID-19. However, traditional antibody production is hampered by long development times and costly production. Here, we report the rapid isolation and characterization of nanobodies from a synthetic library, known as sybodies (Sb), that target the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. Several binders with low nanomolar affinities and efficient neutralization activity were identified of which Sb23 displayed high affinity and neutralized pseudovirus with an IC50 of 0.6 µg/ml. A cryo-EM structure of the spike bound to Sb23 showed that Sb23 binds competitively in the ACE2 binding site. Furthermore, the cryo-EM reconstruction revealed a novel conformation of the spike where two RBDs are in the ‘up’ ACE2-binding conformation. The combined approach represents an alternative, fast workflow to select binders with neutralizing activity against newly emerging viruses.

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Sustained Neutralizing Antibodies 6 Months Following Infection in 376 Japanese COVID-19 Survivors

Frontiers in Microbiology ◽

10.3389/fmicb.2021.661187 ◽

2021 ◽

Vol 12 ◽

Author(s):

Atsushi Goto ◽

Hirofumi Go ◽

Kei Miyakawa ◽

Yutaro Yamaoka ◽

Norihisa Ohtake ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Spike Protein ◽

Test Results ◽

Serum Samples ◽

Factors Associated ◽

Antibody Titers ◽

Spearman’S Correlation

Objective: There is scarce evidence regarding the long-term persistence of neutralizing antibodies among coronavirus disease 2019 (COVID-19) survivors. This study determined neutralizing antibody titers (NT50) and antibodies against spike protein (SP) or nucleocapsid protein (NP) antigens approximately 6 months after the diagnosis of COVID-19.Methods: COVID-19 survivors in Japan were recruited. Serum samples and data related to patients’ characteristics and COVID-19 history were collected. NT50 and titers of antibodies against NP and SP antigens were measured at 20–32 weeks after the first positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results. Factors associated with NT50 were identified using the multivariable linear regression and the correlations among NT50 and titers of immunoglobulin G (IgG) and total immunoglobulins (Igs) against NP and SP were assessed by Spearman’s correlation.Results: Among 376 participants (median [range] days after testing positive for SARS-CoV-2, 180 (147–224); median [range] years of age, 50 (20–78); 188 [50%] male), most tested positive for NT50 (n = 367, 98%), SP-IgG (n = 344, 91%), SP-total Ig (n = 369, 98%), NP-IgG (n = 314, 84%), and NP-total Ig (n = 365, 97%). Regression analysis indicated that higher BMI, fever, and the requirement of mechanical ventilation or extracorporeal membrane oxygenation were significantly associated with higher NT50. Anti-SP antibodies correlated moderately with NT50 (Spearman’s correlation: 0.63 for SP IgG; 0.57 for SP-total Ig), while the correlation was weak for anti-NP antibodies (0.37 for NP IgG; 0.32 for NP-total Ig).Conclusions: Most COVID-19 survivors had sustained neutralizing antibodies and tested positive for SP-total Ig and NP-total Ig approximately 6 months after infection.

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Enhanced protective immunity against SARS-CoV-2 elicited by a VSV vector expressing a chimeric spike protein

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-021-00797-9 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Hongyue Li ◽

Yuhang Zhang ◽

Dong Li ◽

Yong-Qiang Deng ◽

Hongde Xu ◽

...

Keyword(s):

Genetic Similarity ◽

Protective Immunity ◽

Neutralizing Antibody ◽

Cross Reactivity ◽

Cellular Receptor ◽

Receptor Binding Domain ◽

Wild Type ◽

Independent Manner ◽

Recombinant Viruses ◽

Humoral Immune

AbstractSARS-CoV-2 and SARS-CoV are genetically related coronavirus and share the same cellular receptor ACE2. By replacing the VSV glycoprotein with the spikes (S) of SARS-CoV-2 and SARS-CoV, we generated two replication-competent recombinant viruses, rVSV-SARS-CoV-2 and rVSV-SARS-CoV. Using wild-type and human ACE2 (hACE2) knock-in mouse models, we found a single dose of rVSV-SARS-CoV could elicit strong humoral immune response via both intranasal (i.n.) and intramuscular (i.m.) routes. Despite the high genetic similarity between SARS-CoV-2 and SARS-CoV, no obvious cross-neutralizing activity was observed in the immunized mice sera. In macaques, neutralizing antibody (NAb) titers induced by one i.n. dose of rVSV-SARS-CoV-2 were eight-fold higher than those by a single i.m. dose. Thus, our data indicates that rVSV-SARS-CoV-2 might be suitable for i.n. administration instead of the traditional i.m. immunization in human. Because rVSV-SARS-CoV elicited significantly stronger NAb responses than rVSV-SARS-CoV-2 in a route-independent manner, we generated a chimeric antigen by replacing the receptor binding domain (RBD) of SARS-CoV S with that from the SARS-CoV-2. rVSV expressing the chimera (rVSV-SARS-CoV/2-RBD) induced significantly increased NAbs against SARS-CoV-2 in mice and macaques than rVSV-SARS-CoV-2, with a safe Th1-biased response. Serum immunized with rVSV-SARS-CoV/2-RBD showed no cross-reactivity with SARS-CoV. hACE2 mice receiving a single i.m. dose of either rVSV-SARS-CoV-2 or rVSV-SARS-CoV/2-RBD were fully protected against SARS-CoV-2 challenge without obvious lesions in the lungs. Our results suggest that transplantation of SARS-CoV-2 RBD into the S protein of SARS-CoV might be a promising antigen design for COVID-19 vaccines.

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