An automated chemiluminescent immunoassay (CLIA) detects SARS-CoV-2 Neutralizing antibody levels in COVID-19 patients and vaccinees

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.

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Long-Term Longitudinal Evaluation of Six Commercial Immunoassays for the Detection of IgM and IgG Antibodies against SARS CoV-2

Viruses ◽

10.3390/v13071244 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1244

Author(s):

Iulia Nedelcu ◽

Raluca Jipa ◽

Roxana Vasilescu ◽

Cristian Băicuș ◽

Costin-Ioan Popescu ◽

...

Keyword(s):

Clinical Performance ◽

Sample Selection ◽

Early Time ◽

Humoral Response ◽

High Specificity ◽

Data Interpretation ◽

Serum Samples ◽

Chemiluminescent Immunoassay ◽

Chemiluminescent Microparticle Immunoassay ◽

Antibody Levels

The number of serological assays for SARS-CoV-2 has skyrocketed in the past year. Concerns have been raised regarding their performance characteristics, depending on the disease severity and the time of the analysis post-symptom onset (PSO). Thus, independent validations using an unbiased sample selection are required for meaningful serology data interpretation. We aimed to assess the clinical performance of six commercially available assays, the seroconversion, and the dynamics of the humoral response to SARS-CoV-2 infection. The study included 528 serum samples from 156 patients with follow-up visits up to six months PSO and 161 serum samples from healthy people. The IgG/total antibodies positive percentage increased and remained above 95% after six months when chemiluminescent immunoassay (CLIA) IgG antiS1/S2 and electro-chemiluminescent assay (ECLIA) total antiNP were used. At early time points PSO, chemiluminescent microparticle immunoassay (CMIA) IgM antiS achieved the best sensitivity. IgM and IgG appear simultaneously in most circumstances, and when performed in parallel the sensitivity increases. The severe and the moderate clinical forms were significantly associated with higher seropositivity percentage and antibody levels. High specificity was found in all evaluated assays, but the sensitivity was variable depending on the time PSO, severity of disease, detection method and targeted antigen.

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Induction of long-lived germinal centers associated with persisting antigen after viral infection.

Journal of Experimental Medicine ◽

10.1084/jem.183.5.2259 ◽

1996 ◽

Vol 183 (5) ◽

pp. 2259-2269 ◽

Cited By ~ 132

Author(s):

M F Bachmann ◽

B Odermatt ◽

H Hengartner ◽

R M Zinkernagel

Keyword(s):

T Cell ◽

B Cells ◽

Viral Infection ◽

Neutralizing Antibody ◽

Germinal Centers ◽

Memory B Cells ◽

Specific Memory ◽

Specific Amplification ◽

Antibody Levels ◽

Red Pulp

Vesicular stomatitis virus (VSV) induces an early T cell-independent neutralizing lgM response that is followed by a long-lived, T cell-dependent lgG response. We used the specific amplification factor of several 100x of VSV-virions for immunohistology to analyze the localization of VSV-specific B cells at different time points after immunization. At the peak of the IgM response (day 4), VSV-specific B cells were predominantly present in the red pulp and marginal zone but not in the T area. These B cells were mostly stained in the cytoplasm, characterizing them as antibody secreting cells. By day 6 after immunization, germinal centers (GC) containing surface-stained VSV-specific B cells became detectable and were fully established by day 12. At the same time, large VSV-specific B cell aggregates were present in the red pulp. High numbers of VSV-specific GC associated with persisting antigen were present 1 mo after immunization and later, i.e., considerably longer than has been observed for haptens. Some GC, exhibiting follicular dendritic cells and containing VSV-specific, proliferating B cells were still detectable up to 100 d after immunization. Long-lived GC were also observed after immunization with recombinant VSV-glycoprotein in absence of adjuvants. Thus some anti-virally protective (memory) B cells are cycling and locally proliferate in long-lived GC in association with persisting antigen and therefore seem responsible for long-term maintenance of elevated antibody levels. These observations extend earlier studies with carrier hapten antigens in adjuvant depots or complexed with specific IgG; they are the first to show colocalization of antigen and specific memory B cells and to analyze a protective neutralizing antibody response against an acute viral infection.

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Duration of immunity against COVID-19 after vaccination in Indian subcontinent

10.21203/rs.3.rs-1260289/v1 ◽

2022 ◽

Author(s):

Apoorva Munigela ◽

Sasikala M ◽

Gujjarlapudi Deepika ◽

Anand V Kulkarni ◽

Krishna Vemula ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Booster Dose ◽

Indian Subcontinent ◽

Neutralizing Antibody ◽

Health Concern ◽

Mortality Data ◽

Optimal Timing ◽

Cross Sectional ◽

Mortality And Morbidity ◽

Antibody Levels

Abstract Coronavirus disease (COVID-19) continues to be a major health concern leading to substantial mortality and morbidity across the world. Vaccination is effective in reducing the severity and associated mortality. Data pertaining to the duration of immunity, antibody waning and the optimal timing of booster dose administration is limited. In this cross-sectional study, we assessed the antibody levels in healthcare workers who were fully vaccinated after obtaining Institutional ethics committee approval and informed consent. Whole blood was collected and enumeration of S1/S2 neutralizing antibody levels was carried out using LIAISON SARS-COV-2 S1/S2 IgG assay. A total of 1636 individuals who were vaccinated with Covaxin or Covishield were included. Of these, 52% were males with a median age of 29 years. Diabetes and Hypertension was noted in 2.32% (38/1636) and 2.87% (47/1636) of the individuals. Spike neutralizing antibodies were below the detectable range (<15 AU/ml) in 6.0% (98/1636) of the individuals. Decline in neutralizing antibody was seen in 30% of the individuals above 40 years of age with comorbidities (diabetes and hypertension) after 6 months. These individuals may be prioritized for a booster dose at 6 months.

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Clinical utility of Corona Virus Disease-19 serum IgG, IgM, and neutralizing antibodies and inflammatory markers

10.1101/2021.01.19.21249604 ◽

2021 ◽

Author(s):

Ernst J. Schaefer ◽

Florence Comite ◽

Latha Dulipsingh ◽

Maxine Lang ◽

Jessica Jimison ◽

...

Keyword(s):

Inflammatory Markers ◽

Neutralizing Antibodies ◽

Clinical Utility ◽

Virus Disease ◽

Neutralizing Antibody ◽

Case Finding ◽

Immunoglobulin M ◽

Serum Igg ◽

Older Subjects ◽

Antibody Levels

AbstractMost deaths from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection occur in older subjects. We assessed age effects and clinical utility of serum SARS-CoV-2 immunoglobulin G (IgG), immunoglobulin M (IgM), and neutralizing antibodies and serum inflammatory markers. Serum IgG, IgM, and neutralizing antibody levels were measured using chemiluminescence assays from Diazyme (Poway, CA), while serum interleukin-6 (IL-6), C reactive protein (CRP), and ferritin were measured with immunoassays obtained from Roche (Indianapolis, IN). In 79,005 subjects, IgG and IgM levels were positive (≥1.0 arbitrary units [AU]/mL) in 5.29% and 3.25% of subjects, respectively. In antibody positive subjects, median IgG levels were 3.93 AU/mL if <45 years of age, 10.18 AU/mL if 45-64 years of age, and 10.85 AU/mL if ≥65 years of age (p<0.0001). In SARS-CoV-2 RNA positive cases, family members and exposed subjects (n=1,111), antibody testing was found to be valuable for case finding, and persistent IgM levels were associated with chronic symptoms. In non-hospitalized and hospitalized subjects assessed for SARS-CoV-2 RNA (n=278), median IgG levels in AU/mL were 0.05 in negative subjects (n=100), 14.83 in positive outpatients (n=129), and 30.61 in positive hospitalized patients (n=49, p<0.0001). Neutralizing antibody levels correlated significantly with IgG (r=0.875; p<0.0001). Two or more of the criteria of IL-6 ≥10 pg/mL, CRP ≥10 mg/L, and/or IgM >1.0 AU/mL occurred in 97.7% of inpatients versus 1.8% of outpatients (>50-fold relative risk, C statistic 0.986, p<0.0001). Our data indicate that: 1) IgG levels are significantly higher in positive older subjects, possibly to compensate for decreased cellular immunity with aging; 2) IgG levels are important for case finding in family clusters; 3) IgG levels are significantly correlated with neutralizing antibody levels; 4) persistently elevated IgM levels are associated with chronic disease; and 5) markedly elevated IL-6, hs-CRP, and/or positive IgM accurately identify SARS-CoV-2 RNA positive subjects requiring hospitalization.

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Survey of fox trappers in northern Alaska for rabies antibody

Epidemiology and Infection ◽

10.1017/s0950268800051554 ◽

1994 ◽

Vol 113 (1) ◽

pp. 137-141 ◽

Cited By ~ 22

Author(s):

E. H. Follmann ◽

D. G. Ritter ◽

M. Beller

Keyword(s):

Rabies Virus ◽

Neutralizing Antibody ◽

World Health ◽

Antibody Concentration ◽

Alopex Lagopus ◽

Arctic Foxes ◽

Health Organization ◽

Antibody Levels ◽

Northern Alaska ◽

Rabies Vaccination

SUMMARYThe purpose of this research was to determine whether trappers in northern Alaska acquired immunity to rabies virus from non-bite exposures while trapping and skinning arctic foxes (Alopex lagopus). In coastal Alaska recurring epizootics presumably provide trappers ample opportunity for contact with rabid animals. Serum neutralization analyses of blood samples collected from 26 individuals were conducted. All but three had negative rabies neutralizing antibody levels (< 0·05 I.U./ml). Two of these had previously received rabies vaccine but one individual who had trapped for about 47 years with an estimated harvest of over 3000 foxes and who had never received pre- or post-exposure rabies vaccination had a rabies serum neutralizing antibody concentration of 2·30 I.U./ml. This represents the first report of an unvaccinated person acquiring rabies virus antibody with a titre above the 0·5 I.U./ml level considered acceptable by the World Health Organization.

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Neutralizing Antibody Responses in COVID-19 Convalescent Sera

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa673 ◽

2020 ◽

Vol 223 (1) ◽

pp. 47-55 ◽

Cited By ~ 1

Author(s):

William T Lee ◽

Roxanne C Girardin ◽

Alan P Dupuis ◽

Karen E Kulas ◽

Anne F Payne ◽

...

Keyword(s):

Neutralizing Antibodies ◽

High Titer ◽

Experimental Treatment ◽

Neutralizing Antibody ◽

Maximal Activity ◽

The United States ◽

Enzyme Linked Immunosorbent Assay ◽

United States Food ◽

Antibody Titers ◽

Antibody Levels

Abstract Passive transfer of antibodies from COVID-19 convalescent patients is being used as an experimental treatment for eligible patients with SARS-CoV-2 infections. The United States Food and Drug Administration’s (FDA) guidelines for convalescent plasma initially recommended target antibody titers of 160. We evaluated SARS-CoV-2 neutralizing antibodies in sera from recovered COVID-19 patients using plaque reduction neutralization tests (PRNT) at moderate (PRNT50) and high (PRNT90) stringency thresholds. We found that neutralizing activity significantly increased with time post symptom onset (PSO), reaching a peak at 31–35 days PSO. At this point, the number of sera having neutralizing titers of at least 160 was approximately 93% (PRNT50) and approximately 54% (PRNT90). Sera with high SARS-CoV-2 antibody levels (>960 enzyme-linked immunosorbent assay titers) showed maximal activity, but not all high-titer sera contained neutralizing antibody at FDA recommended levels, particularly at high stringency. These results underscore the value of serum characterization for neutralization activity.

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Dengue Virus Neutralizing Antibody Levels Associated with Protection from Infection in Thai Cluster Studies

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0003230 ◽

2014 ◽

Vol 8 (10) ◽

pp. e3230 ◽

Cited By ~ 60

Author(s):

Darunee Buddhari ◽

Jared Aldstadt ◽

Timothy P. Endy ◽

Anon Srikiatkhachorn ◽

Butsaya Thaisomboonsuk ◽

...

Keyword(s):

Dengue Virus ◽

Neutralizing Antibody ◽

Antibody Levels

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Infectious Bursal Disease Emulsified Vaccine: Effect upon Neutralizing-Antibody Levels in the Dam and Subsequent Protection of the Progeny

Avian Diseases ◽

10.2307/1589577 ◽

1979 ◽

Vol 23 (2) ◽

pp. 466 ◽

Cited By ~ 41

Author(s):

Benjamin Lucio ◽

Stephen B. Hitchner

Keyword(s):

Neutralizing Antibody ◽

Infectious Bursal Disease ◽

Bursal Disease ◽

Antibody Levels ◽

Vaccine Effect

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Functional antibody and T-cell immunity following SARS-CoV-2 infection, including by variants of concern, in patients with cancer: the CAPTURE study

10.21203/rs.3.rs-916427/v1 ◽

2021 ◽

Author(s):

Annika Fendler ◽

Lewis Au ◽

Scott Shepherd ◽

Fiona Byrne ◽

Maddalena Cerrone ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Cellular Responses ◽

Patients With Cancer ◽

Cell Immunity ◽

Clinical Annotation ◽

Antibody Titers ◽

Antibody Levels ◽

Immune Profiling ◽

Reactive Antibody

Abstract Patients with cancer have higher COVID-19 morbidity and mortality. Here we present the prospective CAPTURE study (NCT03226886) integrating longitudinal immune profiling with clinical annotation. Of 357 patients with cancer, 118 were SARS-CoV-2-positive, 94 were symptomatic and 2 patients died of COVID-19. In this cohort, 83% patients had S1-reactive antibodies, 82% had neutralizing antibodies against WT, whereas neutralizing antibody titers (NAbT) against the Alpha, Beta, and Delta variants were substantially reduced. Whereas S1-reactive antibody levels decreased in 13% of patients, NAbT remained stable up to 329 days. Patients also had detectable SARS-CoV-2-specific T cells and CD4+ responses correlating with S1-reactive antibody levels, although patients with hematological malignancies had impaired immune responses that were disease and treatment-specific, but presented compensatory cellular responses, further supported by clinical. Overall, these findings advance the understanding of the nature and duration of immune response to SARS-CoV-2 in patients with cancer.

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