SARS-CoV-2 501Y.V2 (B.1.351) elicits cross-reactive neutralizing antibodies

AbstractNeutralization escape by SARS-CoV-2 variants, as has been observed in the 501Y.V2 (B.1.351) variant, has impacted the efficacy of first generation COVID-19 vaccines. Here, the antibody response to the 501Y.V2 variant was examined in a cohort of patients hospitalized with COVID-19 in early 2021 - when over 90% of infections in South Africa were attributed to 501Y.V2. Robust binding and neutralizing antibody titers to the 501Y.V2 variant were detected and these binding antibodies showed high levels of cross-reactivity for the original variant, from the first wave. In contrast to an earlier study where sera from individuals infected with the original variant showed dramatically reduced potency against 501Y.V2, sera from 501Y.V2-infected patients maintained good cross-reactivity against viruses from the first wave. Furthermore, sera from 501Y.V2-infected patients also neutralized the 501Y.V3 (P.1) variant first described in Brazil, and now circulating globally. Collectively these data suggest that the antibody response in patients infected with 501Y.V2 has a broad specificity and that vaccines designed with the 501Y.V2 sequence may elicit more cross-reactive responses.

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Antibody Response to the BNT162b2 mRNA COVID-19 Vaccine in Subjects with Prior SARS-CoV-2 Infection

Viruses ◽

10.3390/v13030422 ◽

2021 ◽

Vol 13 (3) ◽

pp. 422

Author(s):

Federico Gobbi ◽

Dora Buonfrate ◽

Lucia Moro ◽

Paola Rodari ◽

Chiara Piubelli ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Natural Infection ◽

Vaccine Dose ◽

Neutralizing Antibody ◽

Immune Memory ◽

Effective Response ◽

Infected People ◽

Significant Difference ◽

Antibody Titers

Although antibody levels progressively decrease following SARS-CoV-2 infection, the immune memory persists for months. Thus, individuals who naturally contracted SARS-CoV-2 are expected to develop a more rapid and sustained response to COVID-19 vaccines than naïve individuals. In this study, we analyzed the dynamics of the antibody response to the BNT162b2 mRNA COVID-19 vaccine in six healthcare workers who contracted SARS-CoV-2 in March 2020, in comparison to nine control subjects without a previous infection. The vaccine was well tolerated by both groups, with no significant difference in the frequency of vaccine-associated side effects, with the exception of local pain, which was more common in previously infected subjects. Overall, the titers of neutralizing antibodies were markedly higher in response to the vaccine than after natural infection. In all subjects with pre-existing immunity, a rapid increase in anti-spike receptor-binding domain (RBD) IgG antibodies and neutralizing antibody titers was observed one week after the first dose, which seemed to act as a booster. Notably, in previously infected individuals, neutralizing antibody titers 7 days after the first vaccine dose were not significantly different from those observed in naïve subjects 7 days after the second vaccine dose. These results suggest that, in previously infected people, a single dose of the vaccine might be sufficient to induce an effective response.

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COVID-BioB Cohort Study: the neutralizing antibody response to SARS-CoV-2 in symptomatic COVID-19 is persistent and critical for virus control and survival

10.1101/2021.02.17.21251929 ◽

2021 ◽

Author(s):

Stefania Dispinseri ◽

Massimiliano Secchi ◽

Maria Franca Pirillo ◽

Monica Tolazzi ◽

Martina Borghi ◽

...

Keyword(s):

Antibody Response ◽

Symptom Onset ◽

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Therapeutic Interventions ◽

Critical Conditions ◽

Specific Response ◽

Increased Risk ◽

Antibody Titers ◽

Flu Virus

ABSTRACTUnderstanding how antibody to SARS-CoV-2 evolve during infection may provide important insight into therapeutic approaches to prevent fatal COVID-19 illness and vaccines. Here, we profile the antibody response of 162 well-characterized COVID-19 symptomatic patients followed longitudinally for up to eight months from symptom onset. Using two newly developed assays we detect SARS-CoV-2 neutralization and antibodies binding to Spike antigens and nucleoprotein as well as to Spike S2 antigen of seasonal beta-coronaviruses, and to hemagglutinin of the H1N1 flu virus. Presence of neutralizing antibodies withing the first weeks from symptom onset correlates with time to a negative swab result (p=0.002) while lack of neutralization with an increased risk of a fatal disease outcome (HR 2.918, 95%CI 1.321-6.449; p=0.008). Neutralizing antibody titers progressively drop after 5-8 weeks but are still detectable up to 8 months in the majority of recovered patients regardless of age or co-morbidities. IgG to Spike antigens are the best correlate of neutralization. Antibody responses to seasonal coronaviruses are temporary boosted and parallel those to SARS-CoV-2 without dampening the specific response or worsening disease progression. Thus, a compromised immune response to the Spike rather than an enhanced one is a major trait of patients with critical conditions. Patients should be promptly identified and immediately start therapeutic interventions aimed at restoring their immunity.

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Immunogenicity in sheep of Uruguayan commercial vaccines against bovine alphaherpesvirus 1, 5 and bovine pestiviruses

Ciência Rural ◽

10.1590/0103-8478cr20190465 ◽

2020 ◽

Vol 50 (4) ◽

Author(s):

Ingryd Merchioratto ◽

Alana de Almeida Aurélio ◽

Janice Machado Villela ◽

Nicole Vieira Stone ◽

Isac Junior Roman ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Geometric Mean ◽

Neutralizing Antibody ◽

Serological Response ◽

Serum Samples ◽

Post Vaccination ◽

Immunological Responses ◽

Antibody Titers ◽

Low Levels

ABSTRACT: The serological responses induced by four commercial inactivated Uruguayan vaccines against bovine alphaherpesviruses (BoHV)-1 and -5 and bovine pestiviruses (BVDV-1, BVDV-2, and HoBiPeV) were evaluated in sheep. Thirty-seven sheep were immunized twice (day 0 and 25) and their serum samples were tested at different intervals (days 0, 25, 40, 60, and 90) post-vaccination (PV). Among the four vaccines tested, only one (G4) could induce the production of moderate neutralizing antibody titers against BoHV-1 and -5 and BVDV-1 and -2. The G3 vaccine showed a neutralizing serological response against the bovine alphaherpesviruses only. The G1 and G2 vaccines produced extremely low levels of antibodies in a few vaccinated animals only (geometric mean titers (GMT) 2.2). Similar levels of immunological responses were induced by the G4 vaccine against BoHV-1 and -5, and titers of neutralizing antibodies induced in approximately 70% of the animals are known to confer protection (GMT > 8). For bovine pestiviruses, the vaccine stimulated response of G4 against BVDV-2 was higher compared to that against BVDV-1, and extremely low for HoBiPeV. The peak of neutralizing antibodies to BoHV-1 and BVDV-1 was observed on days 40 and 60 PV, respectively. Thereafter, a remarkably decrease in neutralizing antibody response was observed at day 90 PV. These results demonstrated that tested commercial Uruguayan vaccines did not induce a serological response of adequate magnitude and duration. Thus, it is important to periodically review formulations and compositions of commercial vaccines against bovine alphaherpesviruses and pestiviruses.

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Neutralizing Antibody Response to Pseudotype SARS-CoV-2 Differs between mRNA-1273 and BNT162b2 COVID-19 Vaccines and by History of SARS-CoV-2 Infection

10.1101/2021.10.20.21265171 ◽

2021 ◽

Author(s):

Harmony L. Tyner ◽

Mark G. Thompson ◽

Jefferey L. Burgess ◽

Lauren Grant ◽

Manjusha Gaglani ◽

...

Keyword(s):

Antibody Response ◽

Messenger Rna ◽

Neutralizing Antibodies ◽

Geometric Mean ◽

Vaccine Dose ◽

Neutralizing Antibody ◽

Frontline Workers ◽

History Of ◽

Antibody Titers ◽

Polymerase Chain

Background: Data on the development of neutralizing antibodies against SARS-CoV-2 after SARS-CoV-2 infection and after vaccination with messenger RNA (mRNA) COVID-19 vaccines are limited. Methods: From a prospective cohort of 3,975 adult essential and frontline workers tested weekly from August, 2020 to March, 2021 for SARS-CoV-2 infection by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assay irrespective of symptoms, 497 participants had sera drawn after infection (170), vaccination (327), and after both infection and vaccination (50 from the infection population). Serum was collected after infection and each vaccine dose. Serum-neutralizing antibody titers against USA-WA1/2020-spike pseudotype virus were determined by the 50% inhibitory dilution. Geometric mean titers (GMTs) and corresponding fold increases were calculated using t-tests and linear mixed effects models. Results: Among 170 unvaccinated participants with SARS-CoV-2 infection, 158 (93%) developed neutralizing antibodies (nAb) with a GMT of 1,003 (95% CI=766-1,315). Among 139 previously uninfected participants, 138 (99%) developed nAb after mRNA vaccine dose-2 with a GMT of 3,257 (95% CI = 2,596-4,052). GMT was higher among those receiving mRNA-1273 vaccine (GMT =4,698, 95%CI= 3,186-6,926) compared to BNT162b2 vaccine (GMT=2,309, 95%CI=1,825-2,919). Among 32 participants with prior SARS-CoV-2 infection, GMT was 21,655 (95%CI=14,766-31,756) after mRNA vaccine dose-1, without further increase after dose-2. Conclusions: A single dose of mRNA vaccine after SARS-CoV-2 infection resulted in the highest observed nAb response. Two doses of mRNA vaccine in previously uninfected participants resulted in higher nAb to SARS-CoV-2 than after one dose of vaccine or SARS-CoV-2 infection alone. Neutralizing antibody response also differed by mRNA vaccine product.

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Antibodies elicited by SARS-CoV-2 infection and boosted by vaccination neutralize an emerging variant and SARS-CoV-1

10.1101/2021.02.05.21251182 ◽

2021 ◽

Cited By ~ 2

Author(s):

Leonidas Stamatatos ◽

Julie Czartoski ◽

Yu-Hsin Wan ◽

Leah J. Homad ◽

Vanessa Rubin ◽

...

Keyword(s):

South Africa ◽

Immune Response ◽

Monoclonal Antibodies ◽

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Fold Increase ◽

Cd4 T Cell ◽

Cell Responses ◽

Previous Infection ◽

Antibody Titers

AbstractThe emergence of SARS-CoV-2 variants raises concerns about their resistance to neutralizing antibodies elicited from previous infection, or from vaccination. Here we examined whether sera and monoclonal antibodies from convalescent donors, prior to and following a single immunization with the Pfizer or Moderna mRNA vaccines, neutralize the Wuhan-Hu-1 strain and a variant, B.1.351 from South Africa. Pre-vaccination sera weakly neutralized Wuhan-Hu-1 and sporadically neutralized B.1.351. Immunization with either vaccine generated anamnestic B and CD4+ T cell responses and a 1000-fold increase in neutralizing antibody titers against both strains and SARS-CoV-1. Neutralization was likely due to anti-RBD and anti-S2 antibodies. Our study highlights the importance of vaccination of both uninfected and of previously infected subjects, as the elicited immune response will neutralize distinct viral strains.

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Neutralizing Antibody Responses to Human Herpesviruses 6 and 7 Do Not Cross-React with Each Other, and Maternal Neutralizing Antibodies Contribute to Sequential Infection with These Viruses in Childhood

Clinical and Vaccine Immunology ◽

10.1128/cdli.9.2.388-393.2002 ◽

2002 ◽

Vol 9 (2) ◽

pp. 388-393 ◽

Cited By ~ 3

Author(s):

Mariko Yoshida ◽

Sadayoshi Torigoe ◽

Kumiko Ikeue ◽

Masao Yamada

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Human Herpesvirus ◽

Neutralizing Antibody ◽

Young Group ◽

Adult Group ◽

Dot Blot ◽

Serum Samples ◽

Antibody Titers ◽

Almost All

ABSTRACT Seroprevalence of human herpesvirus 6 (HHV-6) and HHV-7 infections is very high throughout the world, and almost all people are exposed first to HHV-6 and second to HHV-7 in their childhood. However, it is not clear whether the neutralizing (NT) antibody response between each virus is cross-reactive or not. To elucidate the NT antibody response between each virus, 55 serum samples from an adult group (subjects 22 to 88 years old) and 60 serum samples from a young group (subjects 2 to 18 years old) were examined by a dot blot method for detecting viral late antigen. Thirty-nine serum samples obtained from cord bloods and a few serum samples obtained from pediatric patients with exanthem subitum were also examined to assess the maternal transferred NT antibodies against each virus. The NT antibody titers against HHV-7 in the adult group remained high throughout all the individuals, and none were negative. Those against HHV-6 were high values in the young group but low values, including negative values (three samples), in the adult group. These results suggested that the NT antibody response to either HHV-6 or HHV-7 in each individual was specific to each virus and did not cross-react with each other. In the adult group, the NT antibody response to HHV-6 decreased, while that to HHV-7 remained high throughout all the individuals. Maternal transferred NT antibody titers against HHV-7 were higher and remained longer after birth than those of HHV-6, and these findings were in accord with the clinical observation that HHV-6 infection usually occurs earlier than HHV-7 infection.

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SARS-CoV-2 RBD trimer protein adjuvanted with Alum-3M-052 protects from SARS-CoV-2 infection and immune pathology in the lung

Nature Communications ◽

10.1038/s41467-021-23942-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Nanda Kishore Routhu ◽

Narayanaiah Cheedarla ◽

Venkata Satish Bollimpelli ◽

Sailaja Gangadhara ◽

Venkata Viswanadh Edara ◽

...

Keyword(s):

Antibody Response ◽

Antibody Titer ◽

Neutralizing Antibodies ◽

Rhesus Macaques ◽

Neutralizing Antibody ◽

Significant Loss ◽

Lung Pathology ◽

Live Virus ◽

Suitable Candidate ◽

Immune Pathology

AbstractThere is a great need for the development of vaccines that induce potent and long-lasting protective immunity against SARS-CoV-2. Multimeric display of the antigen combined with potent adjuvant can enhance the potency and longevity of the antibody response. The receptor binding domain (RBD) of the spike protein is a primary target of neutralizing antibodies. Here, we developed a trimeric form of the RBD and show that it induces a potent neutralizing antibody response against live virus with diverse effector functions and provides protection against SARS-CoV-2 challenge in mice and rhesus macaques. The trimeric form induces higher neutralizing antibody titer compared to monomer with as low as 1μg antigen dose. In mice, adjuvanting the protein with a TLR7/8 agonist formulation alum-3M-052 induces 100-fold higher neutralizing antibody titer and superior protection from infection compared to alum. SARS-CoV-2 infection causes significant loss of innate cells and pathology in the lung, and vaccination protects from changes in innate cells and lung pathology. These results demonstrate RBD trimer protein as a suitable candidate for vaccine against SARS-CoV-2.

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Towards Quantitative and Standardized Serological and Neutralization Assays for COVID-19

International Journal of Molecular Sciences ◽

10.3390/ijms22052723 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2723

Author(s):

Linhua Tian ◽

Elzafir B. Elsheikh ◽

Paul N. Patrone ◽

Anthony J. Kearsley ◽

Adolfas K. Gaigalas ◽

...

Keyword(s):

Flow Cytometry ◽

Vaccine Development ◽

Neutralizing Antibody ◽

Epidemiologic Studies ◽

Cross Reactivity ◽

Receptor Binding Domain ◽

Proof Of Concept ◽

Reference Standard ◽

Improve Measurement ◽

Antibody Titers

Quantitative and robust serology assays are critical measurements underpinning global COVID-19 response to diagnostic, surveillance, and vaccine development. Here, we report a proof-of-concept approach for the development of quantitative, multiplexed flow cytometry-based serological and neutralization assays. The serology assays test the IgG and IgM against both the full-length spike antigens and the receptor binding domain (RBD) of the spike antigen. Benchmarking against an RBD-specific SARS-CoV IgG reference standard, the anti-SARS-CoV-2 RBD antibody titer was quantified in the range of 37.6 µg/mL to 31.0 ng/mL. The quantitative assays are highly specific with no correlative cross-reactivity with the spike proteins of MERS, SARS1, OC43 and HKU1 viruses. We further demonstrated good correlation between anti-RBD antibody titers and neutralizing antibody titers. The suite of serology and neutralization assays help to improve measurement confidence and are complementary and foundational for clinical and epidemiologic studies.

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Titers of Neutralizing Antibodies against SARS-CoV-2 Are Independent of Symptoms of Non-Severe COVID-19 in Young Adults

Viruses ◽

10.3390/v13020284 ◽

2021 ◽

Vol 13 (2) ◽

pp. 284

Author(s):

Hulda R. Jonsdottir ◽

Michel Bielecki ◽

Denise Siegrist ◽

Thomas W. Buehrer ◽

Roland Züst ◽

...

Keyword(s):

Young Adults ◽

Neutralizing Antibodies ◽

Severe Disease ◽

Humoral Response ◽

Neutralizing Antibody ◽

Neutralization Assay ◽

Asymptomatic Infection ◽

Homogeneous Population ◽

Humoral Immune ◽

Antibody Titers

Neutralizing antibodies are an important part of the humoral immune response to SARS-CoV-2. It is currently unclear to what extent such antibodies are produced after non-severe disease or asymptomatic infection. We studied a cluster of SARS-CoV-2 infections among a homogeneous population of 332 predominantly male Swiss soldiers and determined the neutralizing antibody response with a serum neutralization assay using a recombinant SARS-CoV-2-GFP. All patients with non-severe COVID-19 showed a swift humoral response within two weeks after the onset of symptoms, which remained stable for the duration of the study. One month after the outbreak, titers in COVID-19 convalescents did not differ from the titers of asymptomatically infected individuals. Furthermore, symptoms of COVID-19 did not correlate with neutralizing antibody titers. Therefore, we conclude that asymptomatic infection can induce the same humoral immunity as non-severe COVID-19 in young adults.

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Characterization of Pre-F-GCN4t, a Modified Human Respiratory Syncytial Virus Fusion Protein Stabilized in a Noncleaved Prefusion Conformation

Journal of Virology ◽

10.1128/jvi.02437-16 ◽

2017 ◽

Vol 91 (13) ◽

Cited By ~ 18

Author(s):

Normand Blais ◽

Martin Gagné ◽

Yoshitomo Hamuro ◽

Patrick Rheault ◽

Martine Boyer ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Antibody Response ◽

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Human Respiratory Syncytial Virus ◽

Vaccine Antigen ◽

Significant Advance ◽

F Protein ◽

Syncytial Virus

ABSTRACT The human respiratory syncytial virus (hRSV) fusion (F) protein is considered a major target of the neutralizing antibody response to hRSV. This glycoprotein undergoes a major structural shift from the prefusion (pre-F) to the postfusion (post-F) state at the time of virus-host cell membrane fusion. Recent evidences suggest that the pre-F state is a superior target for neutralizing antibodies compared to the post-F state. Therefore, for vaccine purposes, we have designed and characterized a recombinant hRSV F protein, called Pre-F-GCN4t, stabilized in a pre-F conformation. To show that Pre-F-GCN4t does not switch to a post-F conformation, it was compared with a recombinant post-F molecule, called Post-F-XC. Pre-F-GCN4t was glycosylated and trimeric and displayed a conformational stability different from that of Post-F-XC, as shown by chemical denaturation. Electron microscopy analysis suggested that Pre-F-GCN4t adopts a lollipop-like structure. In contrast, Post-F-XC had a typical elongated conical shape. Hydrogen/deuterium exchange mass spectrometry demonstrated that the two molecules had common rigid folding core and dynamic regions and provided structural insight for their biophysical and biochemical properties and reactivity. Pre-F-GCN4t was shown to deplete hRSV-neutralizing antibodies from human serum more efficiently than Post-F-XC. Importantly, Pre-F-GCN4t was also shown to bind D25, a highly potent monoclonal antibody specific for the pre-F conformation. In conclusion, this construct presents several pre-F characteristics, does not switch to the post-F conformation, and presents antigenic features required for a protective neutralizing antibody response. Therefore, Pre-F-GCN4t can be considered a promising candidate vaccine antigen. IMPORTANCE Human respiratory syncytial virus (RSV) is a global leading cause of infant mortality and adult morbidity. The development of a safe and efficacious RSV vaccine remains an important goal. The RSV class I fusion (F) glycoprotein is considered one of the most promising vaccine candidates, and recent evidences suggest that the prefusion (pre-F) state is a superior target for neutralizing antibodies. Our study presents the physicochemical characterization of Pre-F-GCN4t, a molecule designed to be stabilized in the pre-F conformation. To confirm its pre-F conformation, Pre-F-GCN4t was analyzed in parallel with Post-F-XC, a molecule in the post-F conformation. Our results show that Pre-F-GCN4t presents characteristics of a stabilized pre-F conformation and support its use as an RSV vaccine antigen. Such an antigen may represent a significant advance in the development of an RSV vaccine.

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