scholarly journals Antibody response and viraemia during the course of severe acute respiratory syndrome (SARS)-associated coronavirus infection

2004 ◽  
Vol 53 (5) ◽  
pp. 435-438 ◽  
Author(s):  
Weijun Chen ◽  
Zuyuan Xu ◽  
Jingsong Mu ◽  
Ling Yang ◽  
Haixue Gan ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Antibody Response ◽  
Time Course ◽  
Recovery Phase ◽  
Antibody Responses ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Blood Samples ◽  
Convalescent Phase ◽  
Coronavirus Infection

To understand the time-course of viraemia and antibody responses to severe acute respiratory syndrome-associated coronavirus (SARS-CoV), RT-PCR and ELISA were used to assay 376 blood samples from 135 SARS patients at various stages of the illness, including samples from patients who were in their early convalescent phase. The results showed that IgM antibodies decreased and became undetectable 11 weeks into the recovery phase. IgG antibodies, however, remained detectable for a period beyond 11 weeks and were found in 100 % of patients in the early convalescent phase. SARS-CoV viraemia mainly appeared 1 week after the onset of illness and then decreased over a period of 1 month, becoming undetectable in the blood samples of the convalescent patients. At the peak of viraemia, viral RNA was detectable in 75 % of blood samples from patients who were clinically diagnosed with SARS 1 or 2 weeks before the test.

scholarly journals Persistence of serum and saliva antibody responses to SARS-CoV-2 spike antigens in patients with COVID-19

2020 ◽  
Vol 5 (52) ◽  
pp. eabe5511
Author(s):  
Baweleta Isho ◽  
Kento T. Abe ◽  
Michelle Zuo ◽  
Alainna J. Jamal ◽  
Bhavisha Rathod ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Antibody Response ◽  
Receptor Binding ◽  
Antibody Responses ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Igg Antibodies ◽  
Surrogate Measure ◽  
Antibody Levels ◽  
Negative Controls

Although the antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been extensively studied in blood, relatively little is known about the antibody response in saliva and its relationship to systemic antibody levels. Here, we profiled by enzyme-linked immunosorbent assays (ELISAs) immunoglobulin G (IgG), IgA, and IgM responses to the SARS-CoV-2 spike protein (full-length trimer) and its receptor binding domain (RBD) in serum and saliva of acute and convalescent patients with laboratory-diagnosed coronavirus disease 2019 (COVID-19) ranging from 3 to 115 days postsymptom onset (PSO), compared with negative controls. Anti–SARS-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16 to 30 days PSO. Longitudinal analysis revealed that anti–SARS-CoV-2 IgA and IgM antibodies rapidly decayed, whereas IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. Last, IgG, IgM, and, to a lesser extent, IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in most of the patients with COVID-19 for at least 3 months PSO. IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.

scholarly journals Antibody response in COVID-19 patients with and without re-positive RT-PCR results during the convalescent phase

2021 ◽  
Author(s):  
Jing Peng ◽  
Zhi-Yong Liu ◽  
Xiao-Juan Yu ◽  
Xiao-Yan Chen ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Antibody Response ◽  
Rt Pcr ◽  
Convalescent Phase

scholarly journals Antibody Responses in Cats Following Primary and Annual Vaccination against Feline Immunodeficiency Virus (FIV) with an Inactivated Whole-Virus Vaccine (Fel-O-Vax® FIV)

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 470
Author(s):  
Mark Westman ◽  
Dennis Yang ◽  
Jennifer Green ◽  
Jacqueline Norris ◽  
Richard Malik ◽  
...  
Keyword(s):  
Antibody Response ◽  
Virus Vaccine ◽  
Point Of Care ◽  
Primary Vaccination ◽  
Antibody Responses ◽  
Blood Samples ◽  
Study Results ◽  
Elisa Testing ◽  
Primary Antibody Response ◽  
Residual Blood

Although the antibody response induced by primary vaccination with Fel-O-Vax® FIV (three doses, 2–4 weeks apart) is well described, the antibody response induced by annual vaccination with Fel-O-Vax® FIV (single dose every 12 months after primary vaccination) and how it compares to the primary antibody response has not been studied. Residual blood samples from a primary FIV vaccination study (n = 11), and blood samples from cats given an annual FIV vaccination (n = 10), were utilized. Samples from all 21 cats were tested with a commercially available PCR assay (FIV RealPCRTM), an anti-p24 microsphere immunoassay (MIA), an anti-FIV transmembrane (TM; gp40) peptide ELISA, and a range of commercially available point-of-care (PoC) FIV antibody kits. PCR testing confirmed all 21 cats to be FIV-uninfected for the duration of this study. Results from MIA and ELISA testing showed that both vaccination regimes induced significant antibody responses against p24 and gp40, and both anti-p24 and anti-gp40 antibodies were variably present 12 months after FIV vaccination. The magnitude of the antibody response against both p24 and gp40 was significantly higher in the primary FIV vaccination group than in the annual FIV vaccination group. The differences in prime versus recall post-vaccinal antibody levels correlated with FIV PoC kit performance. Two FIV PoC kits that detect antibodies against gp40, namely Witness® and Anigen Rapid®, showed 100% specificity in cats recently administered an annual FIV vaccination, demonstrating that they can be used to accurately distinguish vaccination and infection in annually vaccinated cats. A third FIV PoC kit, SNAP® Combo, had 0% specificity in annually FIV-vaccinated cats, and should not be used in any cat with a possible history of FIV vaccination. This study outlines the antibody response to inactivated Fel-O-Vax® FIV whole-virus vaccine, and demonstrates how best to diagnose FIV infection in jurisdictions where FIV vaccination is practiced.

scholarly journals Mucosal versus systemic antibody responses to SARS-CoV-2 antigens in COVID-19 patients

2020 ◽  
Author(s):  
Baweleta Isho ◽  
Kento T Abe ◽  
Michelle Zuo ◽  
Alainna J Jamal ◽  
Bhavisha Rathod ◽  
...  
Keyword(s):  
Antibody Response ◽  
Upper Airway ◽  
Mucosal Immune Response ◽  
Antibody Responses ◽  
Igg Antibodies ◽  
Blood Draw ◽  
Neutralization Activity ◽  
Surrogate Measure ◽  
Antibody Levels ◽  
Negative Controls

While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the mucosal immune response and its relationship to systemic antibody levels. Since SARS-CoV-2 initially replicates in the upper airway, the antibody response in the oral cavity is likely an important parameter that influences the course of infection, but how it correlates to the antibody response in serum is not known. Here, we profile by enzyme linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor binding domain (RBD) in serum (n=496) and saliva (n=90) of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3-115 days post-symptom onset (PSO), compared to negative controls. Anti-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16-30 days PSO. Whereas anti-CoV-2 IgA and IgM antibodies rapidly decayed, IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. In a surrogate neutralization ELISA (snELISA), neutralization activity peaks by 31-45 days PSO and slowly declines, though a clear drop is detected at the last blood draw (105-115 days PSO). Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that systemic and mucosal humoral IgG antibodies are maintained in the majority of COVID-19 patients for at least 3 months PSO. Based on their correlation with each other, IgG responses in saliva may serve as a surrogate measure of systemic immunity.

scholarly journals Can we predict antibody responses in SARS-CoV-2? A cohort analysis

2021 ◽  
Author(s):  
Mary Gaeddert ◽  
Philip Kitchen ◽  
Tobias Broger ◽  
Stefan Weber ◽  
Ralf Bartenschlager ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Cohort Analysis ◽  
Antibody Responses ◽  
High Antibody ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Median Increase ◽  
Antibody Titers

AbstractBackgroundAfter infection with severe acute respiratory syndrome coronavirus (SARS-CoV-2), Immunoglobulin G (IgG) antibodies and virus-specific neutralizing antibodies (nAbs) develop. This study describes antibody responses in a cohort of recovered COVID-19 patients to identify predictors.MethodsWe recruited patients with confirmed SARS-CoV-2 infection from Heidelberg, Germany. Blood samples were collected three weeks after COVID-19 symptoms ended. Participants with high antibody titers were invited for follow-up visits. IgG titers were measured by the Euroimmun Assay, and nAbs titers in a SARS-CoV-2 infection-based assay.Results281 participants were enrolled between April and August 2020 with IgG testing, 145 (51.6%) had nAbs, and 35 (12.5%) had follow-up. The median IgG optical density (OD) ratio was 3.1 (Interquartile range (IQR) 1.6-5.1), and 24.1% (35/145) had a nAb titer>1:80. Higher IgG titers were associated with increased age and more severe disease, and higher nAbs were associated with male gender and CT-value of 25-30 on RT-PCR at diagnosis. The median IgG OD ratio on follow-up was 3.7 (IQR 2.9-5.9), a median increase of 0.5 (IQR −0.3-1.7). Six participants with follow-up nAbs all had titers ≤ 1:80.ConclusionsWhile age and disease severity were correlated with IgG responses, predictive factors for nAbs in convalescent patients remain unclear.

scholarly journals Enhanced SARS-CoV-2 neutralization by dimeric IgA

2020 ◽  
pp. eabf1555 ◽  
Author(s):  
Zijun Wang ◽  
Julio C. C. Lorenzi ◽  
Frauke Muecksch ◽  
Shlomo Finkin ◽  
Charlotte Viant ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Progenitor Cells ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Igg Antibodies ◽  
Viral Spread ◽  
Mucosal Surfaces ◽  
Iga Response ◽  
Secretory Antibodies ◽  
Primary Form

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), primarily infects cells at mucosal surfaces. Serum neutralizing antibody responses are variable and generally low in individuals that suffer mild forms of COVID-19. Although potent IgG antibodies can neutralize the virus, less is known about secretory antibodies such as IgA that might impact the initial viral spread and transmissibility from the mucosa. Here we characterize the IgA response to SARS-CoV-2 in a cohort of 149 convalescent individuals following diagnosis with COVID-19. IgA responses in plasma generally correlated with IgG responses. Further, clones of IgM-, IgG-, and IgA-producing B cells were derived from common progenitor cells. Plasma IgA monomers specific to SARS-CoV-2 proteins were demonstrated to be two-fold less potent than IgG equivalents. However, IgA dimers, the primary form of antibody in the nasopharynx, were on average fifteen times more potent than IgA monomers against the same target. Thus, dimeric IgA responses may be particularly valuable for protection against SARS-CoV-2 and for vaccine efficacy.

scholarly journals Performance of Commercially Available Rapid Serological Assays for the Detection of SARS-CoV-2 Antibodies

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1067
Author(s):  
Anwar M. Hashem ◽  
Rowa Y. Alhabbab ◽  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sharif Hala ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Significant Variation ◽  
High Specificity ◽  
Lateral Flow ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Standard Methods ◽  
Specific Antibodies ◽  
Time Points

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread globally. Although several rapid commercial serological assays have been developed, little is known about their performance and accuracy in detecting SARS-CoV-2-specific antibodies in COVID-19 patient samples. Here, we have evaluated the performance of seven commercially available rapid lateral flow immunoassays (LFIA) obtained from different manufacturers, and compared them to in-house developed and validated ELISA assays for the detection of SARS-CoV-2-specific IgM and IgG antibodies in RT-PCR-confirmed COVID-19 patients. While all evaluated LFIA assays showed high specificity, our data showed a significant variation in sensitivity of these assays, which ranged from 0% to 54% for samples collected early during infection (3–7 days post symptoms onset) and from 54% to 88% for samples collected at later time points during infection (8–27 days post symptoms onset). Therefore, we recommend prior evaluation and validation of these assays before being routinely used to detect IgM and IgG in COVID-19 patients. Moreover, our findings suggest the use of LFIA assays in combination with other standard methods, and not as an alternative.

Paper or Plastic: RT-PCR of BCR-ABL from Blood Spots Stored and Shipped on Paper

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4566-4566
Author(s):  
Olga Sala Torra ◽  
Lan Beppu ◽  
Susan Branford ◽  
Linda Fletcher ◽  
Gooley Ted ◽  
...  
Keyword(s):  
Room Temperature ◽  
Time Course ◽  
Rna Extraction ◽  
Dried Blood Spots ◽  
Rt Pcr ◽  
Fresh Blood ◽  
Blood Samples ◽  
Blood Spots ◽  
Qrt Pcr ◽  
Sample Age

Abstract In many parts of the world, diagnosis and monitoring of CML patients is limited by the availability and cost of molecular testing. In countries without molecular diagnostic capabilities, blood samples can be shipped to central labs, but this is both hampered by sample degradation, and the high costs of shipping. This study explores the method of directly spotting peripheral blood onto a paper template (dried blood spots), with subsequent shipping, RNA extraction, and BCR-ABL testing. Methods: Blood Spots and Shipment. We received dried blood spots from Australia and African countries by mail or courier, and blood from CML patients from our institution were also used for these experiments. 200μL of blood (PB) was pipetted onto Whatman 503 Protein Saver Cards (PSC; Sigma-Aldrich), where each card contains four 50μL spots. Cards were allowed to dry for at least 24 hours at room temperature. For mailing, PSCs were sealed into glassine envelopes with a packet of desiccant, and then placed inside a mailing envelope following DOT and IATA regulation for shipping non-regulated, exempt human specimens. RNA Extraction from Cards and %BCR-ABL determination. Blood spots were incubated with proteinase K followed by RNA isolation using RNeasy Mini Kits (Qiagen). Extracted RNA was quantified using a NanoDrop spectrometer (Thermo Scientific). %BCR-ABL was determined using the automated Cepheid GeneXpert platform or manual two-step quantitative RT-PCR on the 7900HT Fast Real-Time PCR System (Applied Biosystems). Results: Bench top time course: To test for effects of long transit times on RNA quality, we performed a time course study of cards at room temperature (RT) with 5 samples. For each sample, multiple cards were spotted with PB. The cards were then allowed to sit at RT for predetermined amounts of time, up to 42 days, before extracting RNA. We measured RNA integrity for one of the specimens (CML # 5) and found rapid degradation with the RIN number going from 8.7 for the fresh blood to 2.8 after 28 days on the card. However the amplification for both BCR-ABL and ABL differed less than one cycle between the fresh blood and the last time point by manual qRT-PCR (BCR-ABL Ct = 23.63 for fresh blood and 24.06 for day 28 PSC; ABL Ct = 26.69 for fresh blood and 27.64 for day 28 PSC). Figure 1 shows the results of the time course experiment for the 5 samples as a plot of ΔCt versus time in days. BCR-ABL qRT-PCR concordance studies: We compared the %BCR-ABL results obtained in fresh specimen at the institution sending the sample with the %BCR-ABL results we obtained from RNA extracted from PSC using the Cepheid GeneXpert. Paired evaluable results were available for 9 samples with a median WBC = 9.8 x 109/L (range: 3.37x109/L – 85.5x109/L). Samples were 8 to 49 days old at the time of extraction. The amount of RNA input into the GeneXpert reaction ranged from 38.75ng to 1μg. The %BCR-ABL detected ranged from 0.37% to 27% (see Table). The mean absolute difference between fresh blood and PSC BCR-ABL% is 2%; the relative mean percent change for BCR-ABL, using fresh blood as the reference is 13.1% (S.D., 31.2), P = 0.24. Conclusions and future directions: Dried blood spots are relatively inexpensive method to transport blood that preserves enough RNA stability to allow highly accurate BCR-ABL detection, when compared to results performed on an identical platform using fresh peripheral blood samples. Further studies are undergoing to accurately determine the sensitivity of this method and the feasibility of using regular mail for inexpensive transport of specimens. Table 1IDWBC (1000/μL)Sample Age at Spotting (Days)Sample Age at RNA extraction (Days)RNA ng/μlVolume GeneXPert (μL)Paper %BCR-ABL (IS)GeneXpertFresh Blood % BCR-ABL (IS) GeneXpertI1na010426349naI224.101311092745I38009181544naI47.4285102.4*3.1I55.50495241.92I63.61307.4225912I785.5130102102439I812.212912.415128.8I9na1281.5250.37*0.71I103.370273257.85.7I1115.912731102325I126.612714.415na2.3 *%BCR-ABL was manually calculated due to late ABL Cts because of low starting material. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals Modified Vaccinia Ankara Based SARS-CoV-2 Vaccine Expressing Full-Length Spike Induces Strong Neutralizing Antibody Response

2020 ◽  
Author(s):  
Nanda Kishore Routhu ◽  
Sailaja Gangadhara ◽  
Narayanaiah Cheedarla ◽  
Ayalnesh Shiferaw ◽  
Sheikh Abdul Rahman ◽  
...  
Keyword(s):  
Antibody Response ◽  
Room Temperature ◽  
Vaccine Candidate ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Full Length ◽  
Spike Protein ◽  
Strongly Correlated ◽  
Igg Antibodies ◽  
Potential Vaccine

AbstractThere is a great need for the development of vaccines for preventing SARS-CoV-2 infection and mitigating the COVID-19 pandemic. Here, we developed two modified vaccinia Ankara (MVA) based vaccines which express either a membrane anchored full-length spike protein (MVA/S) stabilized in a prefusion state or the S1 region of the spike (MVA/S1) which forms trimers and is secreted. Both immunogens contained the receptor-binding domain (RBD) which is a known target of antibody-mediated neutralization. Following immunizations with MVA/S or MVA/S1, both spike protein recombinants induced strong IgG antibodies to purified full-length SARS-CoV-2 spike protein. The MVA/S induced a robust antibody response to purified RBD, S1 and S2 whereas MVA/S1 induced an antibody response to the S1 region outside of the RBD region. Both vaccines induced an antibody response in the lung and that was associated with induction of bronchus-associated lymphoid tissue. MVA/S but not MVA/S1 vaccinated mice generated robust neutralizing antibody responses against SARS-CoV-2 that strongly correlated with RBD antibody binding titers. Mechanistically, S1 binding to ACE-2 was strong but reduced following prolonged pre-incubation at room temperature suggesting confirmation changes in RBD with time. These results demonstrate MVA/S is a potential vaccine candidate against SARS-CoV-2 infection.

scholarly journals Prevalence of Immunoglobulin G (IgG) Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Evaluation of a Rapid MEDsan IgG Test in Children Seeking Medical Care

2020 ◽  
Author(s):  
Klara M Posfay-Barbe ◽  
Diego O Andrey ◽  
Julien Virzi ◽  
Patrick Cohen ◽  
Fiona Pigny ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Medical Care ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Infection Rate ◽  
Immunoglobulin G ◽  
Gold Standard ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Seropositivity Rate

Abstract In 208 children seeking medical care, the seropositivity rate of anti–SARS-CoV-2 IgG antibodies was 8.7%, suggesting an infection rate similar to that observed in adults but >100-fold the incidence of RT-PCR–confirmed pediatric cases. Compared with the gold-standard combined ELISA + immunofluorescence, the MEDsan IgG rapid diagnostic test performed accurately.

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