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1.
PLoS One ; 17(1): e0262174, 2022.
Article in English | MEDLINE | ID: covidwho-1622354

ABSTRACT

OBJECTIVES: The aim of this study was to evaluate the clinical performance of the Fluorecare SARS-CoV-2 Spike Protein Test Kit, a rapid immunochromatographic assay for SARS-CoV-2 detection. Moreover, we sought to point out the strategy adopted by a local company to lift the lockdown without leading to an increase in the number of COVID-19 cases, by performing a precise and timely health surveillance. METHODS: The rapid Fluorecare SARS-CoV-2 Spike Protein Test was performed immediately after sampling following the manufacturer's instructions. RT-PCRs were performed within 24 hours of specimen collection. A total amount of 253 nasopharyngeal samples from 121 individuals were collected between March 16 and April 2, 2021 and tested. RESULTS: Of 253 nasopharyngeal samples, 11 (9.1%) were positive and 242 (90.9%) were negative for SARS-CoV-2 RNA by RT-PCR assays. The rapid SARS-CoV-2 antigen detection test's mean sensitivity and specificity were 84,6% (95% CI, 54.6-98.1%) and 100% (95% CI, 98.6-100%), respectively. Two false negative test results were obtained from samples with high RT-PCR cycle threshold (Ct). CONCLUSION: Our study suggested that Fluorecare SARS-CoV-2 Spike Protein Test can be introduced into daily diagnostic practice, as its mean sensitivity and specificity follow the standards recommended by WHO and IFCC Task Force. In addition, we underlined how the strategy adopted by a local company to risk assessment and health surveillance was appropriate for infection containment. This real-life scenario gave us the possibility to experience potential approaches aimed to preserve public health and work activities.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/virology , Nasopharynx/virology , Spike Glycoprotein, Coronavirus/genetics , Antigens, Viral/immunology , Communicable Disease Control/methods , False Negative Reactions , False Positive Reactions , Humans , RNA, Viral/genetics , Retrospective Studies , SARS-CoV-2/genetics , Sensitivity and Specificity , Specimen Handling
2.
Cancer Cell ; 40(1): 103-108.e2, 2022 01 10.
Article in English | MEDLINE | ID: covidwho-1596342

ABSTRACT

Patients with cancer are more likely to have impaired immune responses to SARS-CoV-2 vaccines. We study the breadth of responses against SARS-CoV-2 variants after primary vaccination in 178 patients with a variety of tumor types and after booster doses in a subset. Neutralization of alpha, beta, gamma, and delta SARS-CoV-2 variants is impaired relative to wildtype, regardless of vaccine type. Regardless of viral variant, mRNA1273 is the most immunogenic, followed by BNT162b2, and then Ad26.COV2.S. Neutralization of more variants (breadth) is associated with a greater magnitude of wildtype neutralization, and increases with time since vaccination; advancing age associates with a lower breadth. The concentrations of anti-spike protein antibody are a good surrogate for breadth (positive predictive value of =90% at >1,000 U/mL). Booster SARS-CoV-2 vaccines confer enhanced breadth. These data suggest that achieving a high antibody titer is desirable to achieve broad neutralization; a single booster dose with the current vaccines increases the breadth of responses against variants.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Neoplasms/immunology , SARS-CoV-2/immunology , Aged , Aging/immunology , Antigens, Viral/immunology , Female , Humans , Immunization, Secondary , Immunocompromised Host , Immunogenicity, Vaccine , In Vitro Techniques , Male , Middle Aged , Neoplasms/therapy , Spike Glycoprotein, Coronavirus/immunology , Viral Load
3.
Front Immunol ; 12: 795741, 2021.
Article in English | MEDLINE | ID: covidwho-1581316

ABSTRACT

Glycan-masking the vaccine antigen by mutating the undesired antigenic sites with an additional N-linked glycosylation motif can refocus B-cell responses to desired epitopes, without affecting the antigen's overall-folded structure. This study examined the impact of glycan-masking mutants of the N-terminal domain (NTD) and receptor-binding domain (RBD) of SARS-CoV-2, and found that the antigenic design of the S protein increases the neutralizing antibody titers against the Wuhan-Hu-1 ancestral strain and the recently emerged SARS-CoV-2 variants Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2). Our results demonstrated that the use of glycan-masking Ad-S-R158N/Y160T in the NTD elicited a 2.8-fold, 6.5-fold, and 4.6-fold increase in the IC-50 NT titer against the Alpha (B.1.1.7), Beta (B.1.351) and Delta (B.1.617.2) variants, respectively. Glycan-masking of Ad-S-D428N in the RBD resulted in a 3.0-fold and 2.0-fold increase in the IC-50 neutralization titer against the Alpha (B.1.1.7) and Beta (B.1.351) variants, respectively. The use of glycan-masking in Ad-S-R158N/Y160T and Ad-S-D428N antigen design may help develop universal COVID-19 vaccines against current and future emerging SARS-CoV-2 variants.


Subject(s)
Antigens, Viral/immunology , COVID-19/immunology , Epitopes/immunology , Protein Interaction Domains and Motifs/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Adenoviridae/genetics , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antibody Formation/immunology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Disease Models, Animal , Dose-Response Relationship, Immunologic , Female , Genetic Engineering , Genetic Vectors/genetics , Humans , Immunization , Mice , Neutralization Tests , Polysaccharides , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Structure-Activity Relationship
4.
Viruses ; 13(12)2021 12 20.
Article in English | MEDLINE | ID: covidwho-1580419

ABSTRACT

A microarray-based assay to detect IgG and IgM antibodies against betacoronaviruses (SARS-CoV-2, SARS, MERS, OC43, and HKU1), other respiratory viruses and type I interferons (IFN-Is) was developed. This multiplex assay was applied to track antibody cross-reactivity due to previous contact with similar viruses and to identify antibodies against IFN-Is as the markers for severe COVID-19. In total, 278 serum samples from convalescent plasma donors, COVID-19 patients in the intensive care unit (ICU) and patients who recovered from mild/moderate COVID-19, vaccine recipients, prepandemic and pandemic patients with autoimmune endocrine disorders, and a heterogeneous prepandemic cohort including healthy individuals and chronically ill patients were analyzed. The anti-SARS-CoV-2 microarray results agreed well with the ELISA results. Regarding ICU patients, autoantibodies against IFN-Is were detected in 10.5% of samples, and 10.5% of samples were found to simultaneously contain IgM antibodies against more than two different viruses. Cross-reactivity between IgG against the SARS-CoV-2 nucleocapsid and IgG against the OC43 and HKU1 spike proteins was observed, resulting in positive signals for the SARS-CoV-2 nucleocapsid in prepandemic samples from patients with autoimmune endocrine disorders. The presence of IgG against the SARS-CoV-2 nucleocapsid in the absence of IgG against the SARS-CoV-2 spike RBD should be interpreted with caution.


Subject(s)
Antibodies, Viral/immunology , Interferon Type I/immunology , SARS-CoV-2/immunology , Viruses/immunology , Antibodies, Viral/blood , Antigens, Viral/immunology , Autoantibodies/blood , Autoantibodies/immunology , COVID-19/immunology , COVID-19 Serological Testing , Cross Reactions , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Protein Array Analysis , Respiratory Tract Diseases/immunology , Respiratory Tract Diseases/virology , Viruses/classification
5.
Methods Mol Biol ; 2410: 149-175, 2022.
Article in English | MEDLINE | ID: covidwho-1575668

ABSTRACT

Coronaviruses are causative agents of different zoonosis including SARS, MERS, or COVID-19 in humans. The high transmission rate of coronaviruses, the time-consuming development of efficient anti-infectives and vaccines, the possible evolutionary adaptation of the virus to conventional vaccines, and the challenge to cover broad human population worldwide are the major reasons that made it challenging to avoid coronaviruses outbreaks. Although, a plethora of different approaches are being followed to design and develop vaccines against coronaviruses, most of them target subunits, full-length single, or only a very limited number of proteins. Vaccine targeting multiple proteins or even the entire proteome of the coronavirus is yet to come. In the present chapter, we will be discussing multi-epitope vaccine (MEV) and multi-patch vaccine (MPV) approaches to design and develop efficient and sustainably successful strategies against coronaviruses. MEV and MPV utilize highly conserved, potentially immunogenic epitopes and antigenic patches, respectively, and hence they have the potential to target large number of coronavirus proteins or even its entire proteome, allowing us to combat the challenge of its evolutionary adaptation. In addition, the large number of human leukocyte antigen (HLA) alleles targeted by the chosen specific epitopes enables MEV and MPV to cover broader global population.


Subject(s)
COVID-19 , Coronavirus Infections/prevention & control , Epitopes, B-Lymphocyte , Epitopes, T-Lymphocyte , Viral Vaccines , Antigens, Viral/immunology , COVID-19/prevention & control , Humans , Proteome , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Viral Vaccines/immunology
6.
J Med Virol ; 93(12): 6803-6807, 2021 12.
Article in English | MEDLINE | ID: covidwho-1544308

ABSTRACT

We evaluated the Panbio™ COVID-19 Ag Rapid Test Device as a point-of-care diagnostic tool for COVID-19 in 357 patients at a pediatric emergency department. Thirty-four patients tested positive by reverse transcription polymerase chain reaction, of which 24 were positive by the antigen assay. The sensitivity and specificity of the assay were 70.5% and 100%, respectively.


Subject(s)
Antigens, Viral/immunology , COVID-19/diagnosis , COVID-19/immunology , SARS-CoV-2/immunology , COVID-19 Nucleic Acid Testing/methods , COVID-19 Serological Testing/methods , Child , Child, Preschool , Emergency Service, Hospital , Female , Humans , Immunologic Tests/methods , Infant , Male , Nasopharynx/immunology , Nasopharynx/virology , Point-of-Care Testing , Prospective Studies , Sensitivity and Specificity
7.
J Med Virol ; 93(12): 6778-6781, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1544295

ABSTRACT

A high-throughput, fully automated antigen detection test for SARS-CoV-2 is a viable alternative to reverse-transcription polymerase chain reaction (RT-qPCR) for mass screening during outbreaks. In this study, we compared RT-qPCR for viral load and the VITROS® SARS-CoV-2 Antigen Test with reference to the results of the LUMIPULSE® SARS-CoV-2 Ag Test. Of 128 nasopharyngeal swab specimens taken from patients suspected of being infected with SARS-CoV-2, 49 were positive and 79 were negative according to RT-qPCR. Consistent dose-dependent detection with VITROS® assay was successfully achieved when using nasopharyngeal swab specimens with Ct values of 32.0 or lesser, whereas the CLEIA-based LUMIPULSE® assay was able to detect lower viral loads compared with the VITROS® assay. Our results show that the performance of the VITROS® assay was satisfactory for the diagnosis of contagious COVID-19 patients in the clinical setting. Highlights The performance of the VITROS® SARS-CoV-2 Antigen Test was sufficient for the diagnosis of contagious COVID-19. This test showed high sensitivity and specificity in the detection of SARS-CoV-2 in samples with a Ct value of 32 or less.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Immunoenzyme Techniques/methods , Immunologic Tests/methods , SARS-CoV-2/immunology , Antigens, Viral/genetics , Antigens, Viral/immunology , COVID-19/virology , Humans , Mass Screening/methods , Nasopharynx/immunology , Nasopharynx/virology , RNA, Viral/genetics , RNA, Viral/immunology , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2/genetics , Sensitivity and Specificity , Viral Load/genetics , Viral Load/immunology
9.
Front Immunol ; 12: 767347, 2021.
Article in English | MEDLINE | ID: covidwho-1528823

ABSTRACT

Infection with SARS-CoV-2 triggers the simultaneous activation of innate inflammatory pathways including the complement system and the kallikrein-kinin system (KKS) generating in the process potent vasoactive peptides that contribute to severe acute respiratory syndrome (SARS) and multi-organ failure. The genome of SARS-CoV-2 encodes four major structural proteins - the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein. However, the role of these proteins in either binding to or activation of the complement system and/or the KKS is still incompletely understood. In these studies, we used: solid phase ELISA, hemolytic assay and surface plasmon resonance (SPR) techniques to examine if recombinant proteins corresponding to S1, N, M and E: (a) bind to C1q, gC1qR, FXII and high molecular weight kininogen (HK), and (b) activate complement and/or the KKS. Our data show that the viral proteins: (a) bind C1q and activate the classical pathway of complement, (b) bind FXII and HK, and activate the KKS in normal human plasma to generate bradykinin and (c) bind to gC1qR, the receptor for the globular heads of C1q (gC1q) which in turn could serve as a platform for the activation of both the complement system and KKS. Collectively, our data indicate that the SARS-CoV-2 viral particle can independently activate major innate inflammatory pathways for maximal damage and efficiency. Therefore, if efficient therapeutic modalities for the treatment of COVID-19 are to be designed, a strategy that includes blockade of the four major structural proteins may provide the best option.


Subject(s)
Antigens, Viral/immunology , COVID-19/immunology , Complement System Proteins/immunology , Kallikrein-Kinin System , SARS-CoV-2/immunology , Viral Structural Proteins/immunology , Carrier Proteins/genetics , Carrier Proteins/immunology , Hemolysis , Humans , Mitochondrial Proteins/genetics , Mitochondrial Proteins/immunology , Recombinant Proteins/immunology , Viral Structural Proteins/genetics
10.
Bull Exp Biol Med ; 171(2): 230-233, 2021 May.
Article in English | MEDLINE | ID: covidwho-1525548

ABSTRACT

The presence of IgG and IgM antibodies in the venous blood of 76 patients with confirmed COVID-19 infection was determined by ELISA using Russian test systems. Different levels of IgM antibodies to N-protein and receptor binding domain of the Spike protein (RBD) were revealed. The dynamics of IgG antibodies to the whole virion antigen and recombinant antigens showed high values on weeks 4-5 of the disease. The level of IgG antibodies to Nprotein remained low throughout the observation period. The characteristic dynamics of IgG measured using test systems with sorbed whole virion or recombinant spike proteins reflects the duration of the disease.


Subject(s)
Antibodies, Viral/blood , Antigens, Viral/immunology , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , Immunoglobulin G/blood , Immunoglobulin M/blood , Spike Glycoprotein, Coronavirus/immunology , Antigens, Viral/genetics , COVID-19/blood , COVID-19/immunology , COVID-19/virology , Coronavirus Nucleocapsid Proteins/genetics , Enzyme-Linked Immunosorbent Assay , Humans , Immunity, Humoral , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Time Factors , Virion/genetics , Virion/immunology
11.
PLoS One ; 16(11): e0258819, 2021.
Article in English | MEDLINE | ID: covidwho-1511819

ABSTRACT

Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format. While various manufacturers have produced commercially available SARS-Cov2 antigen LFAs, access to validated tests remains difficult or cost prohibitive in low-and middle-income countries. Herein, we present a visually read open-access LFA (OA-LFA) using commercially-available antibodies and materials for the detection of SARS-CoV-2. The LFA yielded a Limit of Detection (LOD) of 4 TCID50/swab of gamma irradiated SARS-CoV-2 virus, meeting the acceptable analytical sensitivity outlined by in World Health Organization target product profile. The open-source architecture presented in this manuscript provides a template for manufacturers around the globe to rapidly design a SARS-CoV2 antigen test.


Subject(s)
Antigens, Viral/immunology , COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , COVID-19/virology , Humans , Limit of Detection , Point-of-Care Systems , RNA, Viral/immunology , Sensitivity and Specificity
13.
Anal Biochem ; 631: 114360, 2021 10 15.
Article in English | MEDLINE | ID: covidwho-1474246

ABSTRACT

To monitor the levels of protecting antibodies raised in the population in response to infection and/or to immunization with SARS-CoV-2, we need a technique that allows high throughput and low-cost quantitative analysis of human IgG antibodies reactive against viral antigens. Here we describe an ultra-fast, high throughput and inexpensive assay to detect SARS-CoV-2 seroconversion in humans. The assay is based on Ni2+ magnetic particles coated with His tagged SARS-CoV-2 antigens. A simple and inexpensive 96 well plate magnetic extraction/homogenization process is described which allows the simultaneous analysis of 96 samples and delivers results in 7 min with high accuracy.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin G/blood , SARS-CoV-2/isolation & purification , Antibodies, Viral/immunology , Antigens, Viral/blood , Antigens, Viral/immunology , COVID-19/blood , COVID-19/immunology , COVID-19 Serological Testing/economics , Enzyme-Linked Immunosorbent Assay/economics , Enzyme-Linked Immunosorbent Assay/methods , Humans , Immunoglobulin G/immunology , Magnets/chemistry , Nickel/chemistry , SARS-CoV-2/immunology , Sensitivity and Specificity , Seroconversion , Time Factors
14.
Front Immunol ; 12: 740708, 2021.
Article in English | MEDLINE | ID: covidwho-1470758

ABSTRACT

SARS-CoV-2 mRNA vaccines have demonstrated high efficacy and immunogenicity, but limited information is currently available on memory B cell generation and long-term persistence. Here, we investigated spike-specific memory B cells and humoral responses in 145 subjects, up to 6 months after the BNT162b2 vaccine (Comirnaty) administration. Spike-specific antibodies peaked 7 days after the second dose and significant antibody titers and ACE2/RBD binding inhibiting activity were still observed after 6 months, despite a progressive decline over time. Concomitant to antibody reduction, spike-specific memory B cells, mostly IgG class-switched, increased in the blood of vaccinees and persisted 6 months after vaccination. Following the in vitro restimulation, circulating memory B cells reactivated and produced spike-specific antibodies. A high frequency of spike-specific IgG+ plasmablasts, identified by computational analysis 7 days after boost, positively correlated with the generation of IgG+ memory B cells at 6 months. These data demonstrate that mRNA BNT162b2 vaccine elicits strong B cell immunity with spike-specific memory B cells that still persist 6 months after vaccination, playing a crucial role for a rapid response to SARS-CoV-2 virus encounter.


Subject(s)
B-Lymphocytes/immunology , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccines, Synthetic/administration & dosage , Adult , Aged , Antibodies, Viral/blood , Antigens, Viral/immunology , Female , Humans , Immunoglobulin G/blood , Immunologic Memory , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Young Adult
15.
Sci Rep ; 11(1): 20323, 2021 10 13.
Article in English | MEDLINE | ID: covidwho-1467136

ABSTRACT

This study aimed to develop a highly sensitive SARS-CoV-2 nucleocapsid antigen assay using the single molecule array (Simoa) technology and compare it with real time RT-PCR as used in routine clinical practice with the ambition to achieve a comparative technical and clinical sensitivity. Samples were available from 148 SARS-CoV-2 real time RT-PCR positive and 73 SARS-CoV-2 real time RT-PCR negative oropharyngeal swabs. For determination of technical sensitivity SARS-CoV-2 virus culture material was used. The samples were treated with lysis buffer and analyzed using both an in-house and a pre-commercial SARS-CoV-2 nucleocapsid antigen assay on Simoa. Both nucleocapsid antigen assays have a technical sensitivity corresponding to around 100 SARS-CoV-2 RNA molecules/mL. Using a cut-off at 0.1 pg/mL the pre-commercial SARS-CoV-2 nucleocapsid antigen assay had a sensitivity of 96% (95% CI 91.4-98.5%) and specificity of 100% (95% CI 95.1-100%). In comparison the in-house nucleocapsid antigen assay had sensitivity of 95% (95% CI 89.3-98.1%) and a specificity of 100% (95% CI 95.1-100%) using a cut-off at 0.01 pg/mL. The two SARS-CoV-2 nucleocapsid antigen assays correlated with r = 0.91 (P < 0.0001). The in-house and the pre-commercial SARS-CoV-2 nucleocapsid antigen assay demonstrated technical and clinical sensitivity comparable to real-time RT-PCR methods for identifying SARS-CoV-2 infected patients and thus can be used clinically as well as serve as a reference method for antigen Point of Care Testing.


Subject(s)
COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Antigens, Viral/immunology , COVID-19 Serological Testing/methods , Coronavirus Nucleocapsid Proteins/analysis , Denmark , Diagnostic Tests, Routine , Humans , Immunoenzyme Techniques , Nasopharynx/virology , Nucleocapsid/analysis , Nucleocapsid/immunology , Phosphoproteins/analysis , Phosphoproteins/immunology , SARS-CoV-2/pathogenicity , Sensitivity and Specificity , Single Molecule Imaging/methods , Virion/chemistry
16.
Viruses ; 13(10)2021 10 06.
Article in English | MEDLINE | ID: covidwho-1463834

ABSTRACT

The search for effective methods to detect patients who excrete a viable virus is one of the urgent tasks of modern biomedicine. In the present study, we examined the diagnostic value of two antigen tests, BIOCREDIT COVID-19 Ag (RapiGEN Inc., Anyang, Korea) and SGTI-flex COVID-19 Ag (Sugentech Inc., Cheongju, Korea), for their diagnostic value in identifying patients who excrete viable SARS-CoV-2. As part of the study, we examined samples from 106 patients who had just been admitted to the hospital and who had undergone quantitative RT-PCR and assessment of viability of SARS-CoV-2 using cell culture. Assessment of the tests' value for detecting samples containing viable virus showed high sensitivity for both tests. Sensitivity was 78.6% (95% CI, from 49.2% to 95.3%) for SGTI-flex COVID-19 Ag and 100% (95% CI, from 76.8% to 100%) for Biocredit COVID-19 Ag. The specificity of rapid tests was significantly higher than that of RT-PCR and was 66.3% (95% CI, from 55.7% to 75.8%) and 67.4% (95% CI, from 56.8% to 76.8%) for SGTI-flex COVID-19 Ag and Biocredit COVID-19 Ag versus 30.4% (95% CI, from 21.3% to 40.9%) obtained for PCR. Thus, for tasks of identifying viable SARS-CoV-2 during screening of conditionally healthy people, as well as monitoring those quarantined, rapid tests show significantly better results.


Subject(s)
Antigens, Viral/analysis , Antigens, Viral/immunology , COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19 Nucleic Acid Testing , Female , Humans , Male , Mass Screening/methods , Middle Aged , Moscow , Point-of-Care Testing , Polymerase Chain Reaction , Sensitivity and Specificity
17.
PLoS One ; 16(10): e0258394, 2021.
Article in English | MEDLINE | ID: covidwho-1456095

ABSTRACT

Rapid antigen (Ag) tests for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provide quick results, do not require specialized technical skills or infrastructure, and can be used as a point-of-care method to prevent the spread of coronavirus disease (COVID-19). The performance of a magnetic force-assisted electrochemical immunoassay-based test, namely the MARK-B COVID-19 Ag test (BBB, Sungnam, Republic of Korea), was evaluated using 170 nasopharyngeal swab specimens and compared to that of RT-PCR and commercial rapid Ag test (STANDARD Q COVID-19 Ag Test, SD Biosensor, Suwon-si, Republic of Korea). The overall sensitivity and specificity of the MARK-B test were 90.0% (95% CI 79.4%-96.2%) and 99.0% (95% CI 95.0%-99.9%), respectively, with a kappa coefficient of 0.908. The correlations between the electrical current values of MARK-B and the Ct values of RT-PCR were -0.898 (E gene, 95% CI -0.938 to -0.834) and -0.914 (RdRp gene, 95% CI -0.948 to -0.860), respectively. The limit of detection of the MARK-B was measured using the viral culture reference samples and found to be 1 x 102 pfu/mL. The magnetic force-assisted electrochemical immunoassay-based Ag test can be used to rapidly detect SARS-CoV-2 infections, and the corresponding fully automated portable device can provide easy readability and semi-quantitative results.


Subject(s)
Antigens, Viral/immunology , COVID-19 Serological Testing , COVID-19 , Electrochemical Techniques , Magnetic Fields , SARS-CoV-2/immunology , COVID-19/diagnosis , COVID-19/immunology , Humans , Immunoassay , Republic of Korea
18.
Microbiol Spectr ; 9(2): e0087021, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1455682

ABSTRACT

The first case of SARS-CoV-2 was discovered in Israel in late February 2020. Three major outbreaks followed, resulting in over 800,000 cases and over 6,000 deaths by April 2021. Our aim was characterization of a serological snapshot of Israeli patients and healthy adults in the early months of the COVID-19 pandemic. Sera from 55 symptomatic COVID-19 patients and 146 healthy subjects (early-pandemic, reverse transcription-quantitative PCR [qRT-PCR]-negative), collected in Israel between March and April 2020, were screened for SARS-CoV-2-specific IgG, IgM, and IgA antibodies, using a 6-plex antigen microarray presenting the whole inactivated virus and five viral antigens: a stabilized version of the spike ectodomain (S2P), spike subunit 1 (S1), receptor-binding-domain (RBD), N-terminal-domain (NTD), and nucleocapsid (NC). COVID-19 patients, 4 to 40 days post symptom onset, presented specific IgG to all of the viral antigens (6/6) in 54 of the 55 samples (98% sensitivity). Specific IgM and IgA antibodies for all six antigens were detected in only 10% (5/55) and 4% (2/55) of the patients, respectively, suggesting that specific IgG is a superior serological marker for COVID-19. None of the qRT-PCR-negative sera reacted with all six viral antigens (100% specificity), and 48% (70/146) were negative throughout the panel. Our findings confirm a low seroprevalence of anti-SARS-CoV-2 antibodies in the Israeli adult population prior to the COVID-19 outbreak. We further suggest that the presence of low-level cross-reacting antibodies in naive individuals calls for a combined, multiantigen analysis for accurate discrimination between naive and exposed individuals. IMPORTANCE A 6-plex protein array presenting the whole inactivated virus and five nucleocapsid and spike-derived SARS-CoV-2 antigens was used to generate a serological snapshot of SARS-CoV-2 seroprevalence and seroconversion in Israel in the early months of the pandemic. Our findings confirm a very low seroprevalence of anti-SARS-CoV-2 antibodies in the Israeli adult population. We further propose that the presence of low-level nonspecific antibodies in naive individuals calls for a combined, multiantigen analysis for accurate discrimination between naive and exposed individuals enabling accurate determination of seroconversion. The developed assay is currently applied to evaluate immune responses to the Israeli vaccine during human phase I/II trials.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/epidemiology , Microarray Analysis/methods , SARS-CoV-2/immunology , Adult , Aged , Antigens, Viral/immunology , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Immunoassay/methods , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Israel/epidemiology , Male , Middle Aged , Phosphoproteins/immunology , Sensitivity and Specificity , Seroepidemiologic Studies , Spike Glycoprotein, Coronavirus/immunology , Young Adult
19.
Nat Commun ; 12(1): 5839, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1454764

ABSTRACT

There is an urgent need to understand the nature of immune responses against SARS-CoV-2, to inform risk-mitigation strategies for people living with HIV (PLWH). Here we show that the majority of PLWH with ART suppressed HIV viral load, mount a detectable adaptive immune response to SARS-CoV-2. Humoral and SARS-CoV-2-specific T cell responses are comparable between HIV-positive and negative subjects and persist 5-7 months following predominately mild COVID-19 disease. T cell responses against Spike, Membrane and Nucleoprotein are the most prominent, with SARS-CoV-2-specific CD4 T cells outnumbering CD8 T cells. We further show that the overall magnitude of SARS-CoV-2-specific T cell responses relates to the size of the naive CD4 T cell pool and the CD4:CD8 ratio in PLWH. These findings suggest that inadequate immune reconstitution on ART, could hinder immune responses to SARS-CoV-2 with implications for the individual management and vaccine effectiveness in PLWH.


Subject(s)
HIV Infections/immunology , HIV Infections/virology , Immunity, Humoral , SARS-CoV-2/physiology , T-Lymphocytes/immunology , Adult , Aged , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antibody Formation/immunology , Antigens, Viral/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/blood , COVID-19/immunology , COVID-19/virology , Cohort Studies , Female , Genome, Human , HIV Infections/blood , Humans , Interferon-gamma/metabolism , Male , Middle Aged , Phenotype , Species Specificity , Tissue Donors
20.
Can Respir J ; 2021: 6590528, 2021.
Article in English | MEDLINE | ID: covidwho-1450631

ABSTRACT

Background: The direct effect of SARS-CoV-2 on the lungs results in increased hospitalization rates of patients with pneumonia. Severe COVID-19 patients often develop ARDS which is associated with poor prognosis. Assessing risk factors for COVID-19 severity is indispensable for implementing and evaluating therapeutic interventions. We investigated the temporal associations between the SARS-CoV-2 antigen (Ag), total Immunoglobulin (Ig) levels, and several laboratory parameters in hospitalized patients with varying degrees of COVID-19 severity. Methods: The SARS-CoV-2 nucleocapsid protein (NP) and total Ig Spike (S) protein-specific antibodies were determined for each patient with lateral flow assays through repeated sampling every two days. Hematological and biochemical parameters were evaluated at the same time points. Results: 40 Greek COVID-19 patients (31 males, 9 females) with a median age of 59.50 ± 16.21 years were enrolled in the study. The median time from symptom onset to hospitalization was 8.0 ± 4.19 days. A significant negative correlation was observed between the SARS-CoV-2 Ag and total Ig levels. The temporal correlation patterns of the SARS-CoV-2 NP Ag and anti-S total Ig levels with laboratory markers varied among patients with differing degrees of COVID-19 severity. Severe-critical cases had lower SARS-CoV-2 Ag and increased total Ig levels as compared to mild-moderate cases. Conclusions: Distinct temporal profiles of the SARS-CoV-2 NP Ag and anti-S total Ig levels may distinguish different groups of COVID-19 severity.


Subject(s)
Antigens, Viral/immunology , COVID-19/virology , Coronavirus Nucleocapsid Proteins/immunology , Immunoglobulins/immunology , Pandemics , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/immunology , Enzyme-Linked Immunosorbent Assay , Female , Follow-Up Studies , Greece/epidemiology , Humans , Male , Middle Aged , Prospective Studies
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