scholarly journals Longitudinal Analysis and Comparison of Six Serological Assays up to Eight Months Post-COVID-19 Diagnosis

2021 ◽  
Vol 10 (9) ◽  
pp. 1815
Author(s):  
Aurélien Aubry ◽  
Baptiste Demey ◽  
Catherine François ◽  
Gilles Duverlie ◽  
Sandrine Castelain ◽  
...  
Keyword(s):  
Immune Response ◽  
Longitudinal Analysis ◽  
Neutralizing Antibody ◽  
Rt Pcr ◽  
Serological Tests ◽  
Antibody Titers ◽  
Term Data

Background: There is much data available concerning the initiation of the immune response after SARS-CoV-2 infection, but long-term data are scarce. Methods: We thus longitudinally evaluated and compared the total and neutralizing immune response of 61 patients to SARS-CoV-2 infection up to eight months after diagnosis by RT–PCR using several commercial assays. Results: Among the 208 samples tested, the percentage of seropositivity was comparable between assays up to four months after diagnosis and then tended to be more heterogeneous between assays (p < 0.05). The percentage of patients with a neutralizing titer decreased from 82% before two months postdiagnosis to 57% after six months. This decrease appeared to be more marked for patients under 65 years old and those not requiring hospitalization. The percentage of serology reversion at 6 months was from 11% with the WANTAI total assay to over 39% with the ABBOTT IgG assay. The neutralizing antibody titers decreased in parallel with the decrease of total antibody titers, with important heterogeneity between assays. Conclusions: In conclusion, serological tests show equivalent sensitivity in the first months after the diagnosis of SARS-CoV-2 infection, but their performance later, postinfection, must be considered when interpreting the results.

scholarly journals Effect of a booster-dose of rabies vaccine on the duration of virus neutralizing antibody titers in bovines

1998 ◽  
Vol 31 (4) ◽  
pp. 367-371 ◽  
Author(s):  
Avelino Albas ◽  
Paulo Eduardo Pardo ◽  
Albério Antonio Barros Gomes ◽  
Fernanda Bernardi ◽  
Fumio Honma Ito
Keyword(s):  
Immune Response ◽  
Neutralizing Antibodies ◽  
Booster Dose ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Rabies Vaccine ◽  
Western Region ◽  
Humoral Immune ◽  
Paulo State ◽  
Antibody Titers

Humoral immune response using inactivated rabies vaccine was studied in 35 nelore cross-bred bovines of western region of São Paulo state. Ninety days after vaccination, 13 (92.8%) animals presented titers 30.5IU/ml, through mouse neutralization test. After 180 days, 9 (64.3%) sera showed titers 30.5IU/ml, after 270 days, only one (7.1%) showed a titer of 0.51IU/ml, and after 360 days, all animals showed titers < 0.5IU/ml. Group of animals receiving booster dose 30 days after vaccination presented, two months after, all with titers > 0.5IU/ml. At 180 days, 17 (80.9%) sera presented titers > 0.5IU/ml; at 270 days, 15 (71.4%), with titers 30.5IU/ml and at 360 days, 4 (19.0%), with titers 30.5IU/ml. Booster-dose ensured high levels of neutralizing antibodies for at least three months, and 240 days after revaccination, 71.4% of animals were found with titers 30.5IU/ml.

scholarly journals Mechanisms of Dysregulated Humoral and Cellular Immunity by SARS-CoV-2

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1027
Author(s):  
Nima Taefehshokr ◽  
Sina Taefehshokr ◽  
Bryan Heit
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Cell Function ◽  
Adaptive Immune Response ◽  
Neutralizing Antibody ◽  
Humoral And Cellular Immunity ◽  
Cell Responses ◽  
Adaptive Immune ◽  
Antibody Titers

The current coronavirus disease 2019 (COVID-19) pandemic, a disease caused by severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), was first identified in December 2019 in China, and has led to thousands of mortalities globally each day. While the innate immune response serves as the first line of defense, viral clearance requires activation of adaptive immunity, which employs B and T cells to provide sanitizing immunity. SARS-CoV-2 has a potent arsenal of mechanisms used to counter this adaptive immune response through processes, such as T cells depletion and T cell exhaustion. These phenomena are most often observed in severe SARS-CoV-2 patients, pointing towards a link between T cell function and disease severity. Moreover, neutralizing antibody titers and memory B cell responses may be short lived in many SARS-CoV-2 patients, potentially exposing these patients to re-infection. In this review, we discuss our current understanding of B and T cells immune responses and activity in SARS-CoV-2 pathogenesis.

scholarly journals A multiplex serological assay for the characterization of IgG immune response to SARS-CoV-2

2021 ◽  
Author(s):  
Etienne Brochot ◽  
Vianney Souplet ◽  
Pauline Follet ◽  
Pauline Ponthieu ◽  
Christophe Olivier ◽  
...  
Keyword(s):  
Immune Response ◽  
Neutralizing Antibody ◽  
Viral Epitope ◽  
Time Period ◽  
Versatile Tool ◽  
Comprehensive Picture ◽  
Long Time ◽  
Antibody Titers ◽  
Combined Detection

Background: In the fight against SARS-COV-2, the development of serological assays based on different antigenic domains represent a versatile tool to get a comprehensive picture of the immune response or differentiate infection from vaccination beyond simple diagnosis. Objectives: Here we use a combination of the Nucleoprotein (NP), the Spike 1 (S1) and Spike 2 (S2) subunits, and the receptor binding domain (RBD) and N-terminal domain (NTD) of the Spike antigens from the Syrius-CoViDiag multiplex IgG assay, to follow the immune response to SARS-CoV-2 infection over a long time period and depending on disease severity. Results: Using a panel of 209 sera collected from 61 patients up to eight months after infection, we observed that most patients develop an immune response against multiple viral epitope, but anti-S2 antibodies seemed to last longer. For all the tested IgGs, we have found higher titers for hospitalized patients than for non-hospitalized ones. Moreover the combination of the five different IgG titers increased the correlation to the neutralizing antibody titers than if considered individually. Conclusion: Multiplex immunoassays have the potential to improve diagnostic performances, especially for ancient infection or mild form of the disease presenting weaker antibody titers. Also the combined detection of anti-NP and anti-Spike-derived domains can be useful to differentiate vaccination from viral infection and accurately assess the antibody potential to neutralize the virus.

scholarly journals Evaluation of high-throughput SARS-CoV-2 serological assays in a longitudinal cohort of mild COVID-19 patients: sensitivity, specificity and association with virus neutralization test

2020 ◽  
Author(s):  
Antonin Bal ◽  
Bruno Pozzetto ◽  
Mary-Anne Trabaud ◽  
Vanessa Escuret ◽  
Muriel Rabilloud ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Healthcare Workers ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Serological Tests ◽  
Course Of Disease ◽  
Antibody Titers ◽  
Sensitivity Specificity

BackgroundThe association between SARS-CoV-2 commercial serological assays and virus neutralization test (VNT) has been poorly explored in mild COVID-19 patients.MethodsA total of 439 serum specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed COVID-19. The sensitivity (determined weekly) of nine commercial serological assays were evaluated. Specificity was assessed using 69 pre-pandemic sera. Correlation, agreement and concordance with the VNT were also assessed on a subset of 170 samples. Area under the ROC curve (AUC) was estimated at several neutralizing antibody titers.ResultsThe Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The specificity was greater than 95% for all tests except for the Euroimmun IgA assay. The overall agreement with the presence of neutralizing antibodies ranged from 62.2% (95%CI; 56.0-68.1) for bioMérieux IgM to 91.2% (87.0-94.2) for Siemens. The lowest negative percent agreement (NPA) was found with the Wantai Total Ab assay (NPA 33% (21.1-48.3)). The NPA for other total Ab or IgG assays targeting the S or the RBD was 80.7% (66.7-89.7), 90.3 (78.1-96.1) and 96.8% (86.8-99.3) for Siemens, bioMérieux IgG and DiaSorin, respectively. None of commercial assays have sufficient performance to detect a neutralizing titer of 80 (AUC<0.76).ConclusionsAlthough some assays presented a better agreement with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute a VNT for the assessment of functional antibody response.

scholarly journals A Combination Adjuvant for the Induction of Potent Antiviral Immune Responses for a Recombinant SARS-CoV-2 Protein Vaccine

2021 ◽  
Vol 12 ◽  
Author(s):  
Sonia Jangra ◽  
Jeffrey J. Landers ◽  
Raveen Rathnasinghe ◽  
Jessica J. O’Konek ◽  
Katarzyna W. Janczak ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibody ◽  
Cellular Responses ◽  
Cross Protection ◽  
Protein Vaccine ◽  
Mucosal Vaccination ◽  
Adaptive Immune ◽  
Antibody Titers ◽  
High Virus

Several SARS-CoV-2 vaccines have received EUAs, but many issues remain unresolved, including duration of conferred immunity and breadth of cross-protection. Adjuvants that enhance and shape adaptive immune responses that confer broad protection against SARS-CoV-2 variants will be pivotal for long-term protection as drift variants continue to emerge. We developed an intranasal, rationally designed adjuvant integrating a nanoemulsion (NE) that activates TLRs and NLRP3 with an RNA agonist of RIG-I (IVT DI). The combination adjuvant with spike protein antigen elicited robust responses to SARS-CoV-2 in mice, with markedly enhanced TH1-biased cellular responses and high virus-neutralizing antibody titers towards both homologous SARS-CoV-2 and a variant harboring the N501Y mutation shared by B1.1.7, B.1.351 and P.1 variants. Furthermore, passive transfer of vaccination-induced antibodies protected naive mice against heterologous viral challenge. NE/IVT DI enables mucosal vaccination, and has the potential to improve the immune profile of a variety of SARS-CoV-2 vaccine candidates to provide effective cross-protection against future drift variants.

Neutralizing antibody titers six months after Comirnaty vaccination: kinetics and comparison with SARS-CoV-2 immunoassays

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrea Padoan ◽  
Chiara Cosma ◽  
Francesco Bonfante ◽  
Foscarina della Rocca ◽  
Francesco Barbaro ◽  
...  
Keyword(s):  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
University Hospital ◽  
Serum Samples ◽  
Viral Neutralization ◽  
Previous Infection ◽  
Antibody Titers ◽  
Males And Females ◽  
Antibody Levels

Abstract Objectives mRNA vaccines, including Comirnaty (BNT162b2 mRNA, BioNTech-Pfizer), elicit high IgG and neutralizing antibody (NAb) responses after the second dose, but the progressive decrease in serum antibodies against SARS-CoV-2 following vaccination have raised questions concerning long-term immunity, decreased antibody levels being associated with breakthrough infections after vaccination, prompting the consideration of booster doses. Methods A total number of 189 Padua University-Hospital healthcare workers (HCW) who had received a second vaccine dose were asked to collect serum samples for determining Ab at 12 (t12) and 28 (t28) days, and 6 months (t6m) after their first Comirnaty/BNT162b2 inoculation. Ab titers were measured with plaque reduction neutralization test (PRNT), and three chemiluminescent immunoassays, targeting the receptor binding domain (RBD), the trimeric Spike protein (trimeric-S), and surrogate viral neutralization tests (sVNT). Results The median percentages (interquartile range) for decrease in antibodies values 6 months after the first dose were 86.8% (67.1–92.8%) for S-RBD IgG, 82% (58.6–89.3%) for trimeric-S, 70.4% (34.5–86.4%) for VNT-Nab, 75% (50–87.5%) for PRNT50 and 75% (50–93.7%) for PRNT90. At 6 months, neither PRNT titers nor VNT-Nab and S-RBD IgG bAb levels correlated with age (p=0.078) or gender (p=0.938), while they were correlated with previous infection (p<0.001). Conclusions After 6 months, a method-independent reduction of around 90% in anti-SARS-CoV-2 antibodies was detected, while no significant differences were found between values of males and females aged between 24 and 65 years without compromised health status. Further efforts to improve analytical harmonization and standardization are needed.

scholarly journals Needle-Free Skin Patch Vaccination Method for Anthrax

2004 ◽  
Vol 72 (2) ◽  
pp. 1181-1183 ◽  
Author(s):  
Gary R. Matyas ◽  
Arthur M. Friedlander ◽  
Gregory M. Glenn ◽  
Stephen Little ◽  
Jianmei Yu ◽  
...  
Keyword(s):  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Adjuvant Activity ◽  
Skin Patch ◽  
Transcutaneous Immunization ◽  
Antibody Titers ◽  
Recombinant Protective Antigen

ABSTRACT Three immunizations of mice with recombinant protective antigen (rPA) by transcutaneous immunization (TCI) induced long-term neutralizing antibody titers that were superior to those obtained with aluminum-adsorbed rPA. In addition, rPA alone exhibited adjuvant activity for TCI. Forty-six weeks after completion of TCI, 100% protection was observed against lethal anthrax challenge.

scholarly journals Microneedle-Based Intradermal Delivery of the Anthrax Recombinant Protective Antigen Vaccine

2006 ◽  
Vol 74 (12) ◽  
pp. 6806-6810 ◽  
Author(s):  
John A. Mikszta ◽  
John P. Dekker ◽  
Noel G. Harvey ◽  
Cheryl H. Dean ◽  
John M. Brittingham ◽  
...  
Keyword(s):  
Immune Response ◽  
Immunoglobulin G ◽  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Antigen Vaccine ◽  
Intradermal Delivery ◽  
Antibody Titers ◽  
Sparing Effect ◽  
Booster Inoculation ◽  
Recombinant Protective Antigen

ABSTRACT The recombinant protective antigen (rPA) of Bacillus anthracis is a promising anthrax vaccine. We compared serum immunoglobulin G levels and toxin-neutralizing antibody titers in rabbits following delivery of various doses of vaccine by microneedle-based intradermal (i.d.) delivery or intramuscular (i.m.) injection using conventional needles. Intradermal delivery required less antigen to induce levels of antibody similar to those produced via i.m. injection during the first 2 weeks following primary and booster inoculation. This dose-sparing effect was less evident at the later stages of the immune response. Rabbits immunized i.d. with 10 μg of rPA displayed 100% protection from aerosol spore challenge, while i.m. injection of the same dose provided slightly lower protection (71%). Groups immunized with lower antigen doses were partially protected (13 to 29%) regardless of the mode of administration. Overall, our results suggest rPA formulated with aluminum adjuvant and administered to the skin by a microneedle-based device is as efficacious as i.m. vaccination.

scholarly journals Immune cell phenotypes associated with disease severity and long-term neutralizing antibody titers after natural dengue virus infection

2021 ◽  
Vol 2 (5) ◽  
pp. 100278
Author(s):  
Angeline Rouers ◽  
Melissa Hui Yen Chng ◽  
Bernett Lee ◽  
Menaka P. Rajapakse ◽  
Kaval Kaur ◽  
...  
Keyword(s):  
Virus Infection ◽  
Dengue Virus ◽  
Disease Severity ◽  
Immune Cell ◽  
Neutralizing Antibody ◽  
Dengue Virus Infection ◽  
Antibody Titers ◽  
Cell Phenotypes
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