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1.
Clin Transl Immunology ; 11(5): e1384, 2022.
Article in English | MEDLINE | ID: covidwho-1849495

ABSTRACT

Objectives: Immunopathology of ongoing COVID-19 global pandemic is not limited solely to pulmonary tissue, but is often associated with multi-organ complications, mechanisms of which are intensely being investigated. In this regard, the interplay between immune, stromal cells and cytokines in pulmonary and extrapulmonary infected tissues, especially in young adults (median age 46 years, range 30-53 years) without comorbidities, remains poorly characterised. Methods: We profiled lung, heart and intestinal autopsy samples from five SARS-CoV-2-infected cases for 18-20 targets to detect immune, cytokine and stromal cell status at subcellular resolution by a novel IHC-based deep-phenotyping technique, iSPOT (immunoSpatial histoPhenOmics using TSA-IHC), to assess spatial and functional patterns of immune response in situ, in lethal COVID-19 infection. Results: SARS-CoV-2-infected autopsy samples exhibit skewed counts of immune populations in all samples with organ-specific dysfunctions. Lung and ileal tissue reveal altered architecture with marked loss of tissue integrity, while lung and heart tissue show severe hyperinflammation marked by elevated TNF-α in heart tissue and additionally IL-6, IFN-γ and IL-10 cytokines in lung samples. Conclusion: With resurgence of infection in younger populations, single-cell cytokine localisation in immune and stromal structures provides important mechanistic insights into organ-specific immunopathology of naïve SARS-CoV-2 infection in the absence of other comorbidities.

2.
Clin Infect Dis ; 2022 May 11.
Article in English | MEDLINE | ID: covidwho-1840043

ABSTRACT

BACKGROUND: Waning antibody levels post-vaccination and the emergence of variants of concern (VOCs) capable of evading protective immunity has raised the need for booster vaccinations. However, which combination of COVID-19 vaccines offers the strongest immune response against Omicron variant is unknown. METHODS: This randomized, subject-blinded, controlled trial assessed the reactogenicity and immunogenicity of different COVID-19 vaccine booster combinations. 100 BNT162b2-vaccinated individuals were enrolled and randomized 1: 1 to either homologous (BNT162b2 + BNT162b2 + BNT162b2; 'BBB') or heterologous mRNA booster vaccine (BNT162b2 + BNT162b2 + mRNA-1273; 'BBM'). Primary endpoint was the level of neutralizing antibodies against SARS-CoV-2 wild-type and VOCs at Day 28. RESULTS: 51 participants were allocated to BBB and 49 to BBM; 50 and 48 respectively were analyzed for safety and immunogenicity outcomes. At Day 28 post-boost, mean SARS-CoV-2 spike antibody titers were lower with BBB (22,382  IU/mL 95% CI, 18,210 to 27,517) vs BBM (29,751  IU/mL 95% CI, 25,281 to 35,011, p = 0.034) as was the median level of neutralizing antibodies: BBB 99.0% (IQR 97.9 to 99.3%) vs BBM 99.3% (IQR 98.8 to 99.5%, p = 0.021). On sub-group analysis, significant differences in mean spike antibody titer and live Omicron neutralization titer was only observed in older adults. Median surrogate neutralizing antibody level against all VOCs was also significantly higher with BBM in older adults, and against Omicron was BBB 72.8% (IQR 54.0 to 84.7%) vs BBM 84.3% (IQR 78.1 to 88.7%, p = 0.0073). Both vaccines were well tolerated. CONCLUSIONS: Heterologous mRNA-1273 booster vaccination induced a stronger neutralizing response against the Omicron variant in older individuals compared with homologous BNT123b2.

3.
J Med Virol ; 94(6): 2460-2470, 2022 06.
Article in English | MEDLINE | ID: covidwho-1748622

ABSTRACT

Coronavirus Disease 2019 (COVID-19) serology has an evolving role in the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, its use in hospitalized patients with acute respiratory symptoms remains unclear. Hospitalized patients with acute respiratory illness admitted to an isolation ward were recruited. All patients had negative nasopharyngeal swab polymerase chain reaction (PCR) for SARS-CoV-2. Serological studies using four separate assays (cPass: surrogate neutralizing enzyme-linked immunosorbent assay [ELISA]; Elecsys: N-antigen based chemiluminescent assay; SFB: S protein flow-based; epitope peptide-based ELISA) were performed on stored plasma collected from patients during the initial hospital stay, and a convalescent visit 4-12 weeks later. Of the 51 patients studied (aged 54, interquartile range 21-84; 62.7% male), no patients tested positive on the Elecsys or cPass assays. Out of 51 patients, 5 had antibodies detected on B-cell Epitope Assay and 3/51 had antibodies detected on SFB assay. These 8 patients with positive serological test to COVID-19 were more likely to have a high-risk occupation (p = 0.039), bacterial infection (p = 0.028), and neutrophilia (p = 0.013) during their initial hospital admission. Discrepant COVID-19 serological findings were observed among those with recent hospital admissions and bacterial infections. The positive serological findings within our cohort raise important questions about the interpretation of sero-epidemiology during the current pandemic.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Female , Fever , Humans , Male , Pandemics , Polymerase Chain Reaction , SARS-CoV-2/genetics
4.
SSRN; 2022.
Preprint in English | SSRN | ID: ppcovidwho-330621

ABSTRACT

Background: Waning antibody levels post-vaccination and the emergence of variants of concern (VOCs) capable of evading protective immunity has raised the need for booster vaccinations. However, which combination of COVID-19 vaccines offers the strongest immune response against Omicron variant is unknown. Methods: This randomized, subject-blinded, controlled trial assess the reactogenicity and immunogenicity of different COVID-19 vaccine booster combinations. 100 BNT162b2-vaccinated individuals were enrolled and randomized 1:1 to either homologous (BNT162b2+BNT162b2+BNT162b2;‘BBB’) or heterologous mRNA booster vaccine (BNT162b2+BNT162b2+mRNA-1273;‘BBM’). Primary endpoint was the level of neutralizing antibodies against SARS-CoV-2 wild-type and VOCs at Day 28. Results: 51 participants were allocated to BBB and 49 to BBM;50 and 48 respectively were analyzed for safety and immunogenicity outcomes. At Day 28 post-boost, mean SARS-CoV-2 spike antibody titers were lower with BBB (22,382 IU/mL 95% CI, 18,210 to 27,517) vs BBM (29,751 IU/mL 95% CI, 25,281 to 35,011, p=0·034) as was the median level of neutralizing antibodies: BBB 99.0% (IQR 97·9 to 99·3%) vs BBM 99.3% (IQR 98·8 to 99·5%, p=0·021). On sub-group analysis, significant differences in mean spike antibody titer and live Omicron neutralization titer was only observed in older adults. Median surrogate neutralizing antibody level against all VOCs was also significantly higher with BBM in older adults, and against Omicron was BBB 72·8% (IQR 54·0 to 84·7%) vs BBM 84·3% (IQR 78·1 to 88·7%, p=0·0073). Both vaccines were well tolerated. Conclusions: Heterologous mRNA-1273 booster vaccination induced a stronger neutralizing response against the Omicron variant in older individuals compared with homologous BNT123b2.

5.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329767

ABSTRACT

The scale and duration of neutralizing antibody responses targeting SARS-CoV-2 viral variants represents a critically important serological parameter that predicts protective immunity for COVID-19. In this study, we present longitudinal data illustrating the impact of age, sex and comorbidities on the kinetics and strength of vaccine-induced neutralizing antibody responses for key variants in an Asian volunteer cohort. We demonstrate a reduction in neutralizing antibody titres across all groups six months post-vaccination and show a marked reduction in the serological binding and neutralizing response targeting Omicron compared to other viral variants. We also highlight the increase in cross-protective neutralizing antibody responses against Omicron induced by a third dose (booster) of vaccine. These data illustrate how key virological factors such as immune escape mutation combined with host factors such as age and sex of the vaccinated individuals influence the strength and duration of cross-protective serological immunity for COVID-19.

6.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329228

ABSTRACT

Trials guidance: The should not exceed 350 words. Please minimize the use of abbreviations and do not cite references in the . The must include the following separate sections:• Background: Over 2021, COVID-19 vaccination programs worldwide focused on raising population immunity through the primary COVID-19 vaccine series. In Singapore two mRNA vaccines (BNT162b2 and mRNA-1273) and the inactivated vaccine CoronaVac are currently authorized under the National Vaccination Programme for use as the primary vaccination series. More than 90% of the Singapore population has received at least one dose of a COVID-19 vaccine as of December 2021. With the demonstration that vaccine effectiveness wanes in the months after vaccination, and the emergence of Omicron which evades host immunity from prior infection and/or vaccination, attention in many countries has shifted to how best to maintain immunity through booster vaccinations. • Methods: The objectives of this phase 3, randomized, subject-blinded, controlled clinical trial are to assess the safety and immunogenicity of heterologous boost COVID-19 vaccine regimens (intervention groups 1-4) compared with a homologous boost regimen (control arm) in up to 600 adult volunteers. As non-mRNA vaccine candidates may enter the study at different time points depending on vaccine availability and local regulatory approval, participants will be randomized at equal probability to the available intervention arms at the time of randomization. Eligible participants will have received two doses of a homologous mRNA vaccine series with BNT162b2 or mRNA-1273 at least six months prior to enrolment. Participants will be excluded if they have a history of confirmed SARS or SARS-CoV-2 infection, are immunocompromised or pregnant. Participants will be monitored for adverse events and serious adverse events by physical examinations, laboratory tests and self-reporting. Blood samples will be collected at serial time points [Pre-vaccination/screening (Day -14 to Day 0), Day 7, Day 28, Day 180, Day 360 post-vaccination] for assessment of antibody and cellular immune parameters. Primary endpoint is the level of anti-SARS-CoV-2 spike immunoglobulins at Day 28 post-booster, and will be measured against wildtype SARS-CoV-2 and variants of concern. Comprehensive immune profiling of the humoral and cellular immune response to vaccination will be performed. • Discussion: This study will provide necessary data to understand the quantity, quality and persistence of the immune response to homologous and heterologous third booster dose of COVID-19 vaccines. This an important step in developing COVID-19 vaccination programs beyond the primary series. Trial registration ClinicalTrials.gov NCT05142319, registered on 2 Dec 2021.

7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-311276

ABSTRACT

Purpose: COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2), has a wide disease spectrum ranging from asymptomatic to severe. While it is widely accepted that specific humoral immune responses are critical in controlling the infection, the relationship between the humoral immune response and disease severity is currently unclear.MethodsUsing a flow cytometry-based assay to detect specific antibodies against full length S protein, we compared the antibody levels between patients from different severity groups. We also analysed the cytokine profiles of patients from different severity groups by multiplex microbead-based immunoassay . ResultsWe found an association between specific IgM, IgA and IgG against the spike protein and disease severity. By comparing the ratio of Th1 IgG1 and IgG3 to Th2 IgG2 and IgG4, we observed that all severity groups exhibited a ratio that was skewed towards a stronger Th1 response over Th2 response. In addition to the strong Th1 response, patients with severe disease also developed a Th2 response, as exemplified by the smaller ratio of IgG1 and IgG3 over IgG2 and IgG4 and the smaller Th1/Th2 cytokine ratios, compared to patients with mild disease severity. ConclusionThe results suggest that acute severity or disease resolution is associated with a specific immunological phenotype. A smaller skew towards a Th1 response over Th2 response, during infection, may contribute to disease progression, while a greater skew towards a Th1 response over Th2 response may contribute to a better disease outcome. This may suggest potential therapeutic approaches to COVID-19 disease management.

8.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-311275

ABSTRACT

Early detection of infections is crucial to limit the spread of coronavirus 2019 disease (COVID-19). Here, we developed a flow cytometry-based assay to detect SARS-CoV-2 Spike protein (S protein) antibodies in COVID-19 patients. The assay detected specific IgM and IgG in COVID-19 patients and also the acquisition of all IgG subclasses, with IgG1 being the most dominant. The antibody response was significantly higher at a later stage of the infection. Furthermore, asymptomatic COVID-19 patients also developed specific IgM and IgG, with IgG1 as the most dominant subclass. Although the antibody levels were lower in asymptomatic infections, the assay was highly sensitive and detected 97% of asymptomatic infections. These findings demonstrated that the assay could be used for serological analysis of symptomatic patients, and also as a sensitive tool to detect asymptomatic infections, which may go undetected.Funding: Biomedical Research Council (BMRC), the A*ccelerate GAP-funded project (ACCL/19-GAP064-R20H-H) from Agency of Science, Technology and Research (A*STAR), and National Medical Research Council (NMRC) COVID-19 Research fund (COVID19RF-001, COVID-19RF-007, COVID-19RF-60).Conflict of Interest: The authors declare no competing interests.Ethical Approval: The study design and protocols for COVID-19, recovered SARS and seasonal human CoV patient cohorts were approved by National Healthcare Group (NHG) Domain Specific Review Board (DSRB) and performed, following ethical guidelines in the approved studies 2012/00917, 2020/00091 and 2020/00076 respectively. Healthy donor samples were collected in accordance with approved studies 2017/2806 and NUS IRB 04-140. Written informed consent was obtained from participants in accordance with the Declaration of Helsinki for Human Research.

9.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-328680

ABSTRACT

Background: On 26 November 2021, the World Health Organization designated the B.1.1.529 lineage of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) as the fifth variant of concern, Omicron. Infections have quickly spread worldwide, but understanding of the viral dynamics and the cytokine and cellular immunological response during infection remain limited. Methods: Detailed patient-level data from 174 age-matched patients with sequence confirmed Omicron or Delta infection admitted to the National Centre for Infectious Diseases, Singapore were analyzed in an observational cohort study. Peripheral blood samples for measurement of SARS-CoV-2 immunological parameters were obtained from a subset. Respiratory samples were collected for viral cultures and correlated to corresponding PCR cycle threshold (Ct) values. Results: Omicron and Delta variant infections in this hospitalized cohort were mild with only 3 (3%) and 14 (16%) developing pneumonia respectively. Omicron infections were more likely to present with sore throat (46.0 vs x23.0%, p=0.005). Neutrophil counts and C-reactive protein (CRP) were significantly lower among the Omicron cohort (Median neutrophil 2.95 [IQR 2.16 – 3.96] vs 4.60 [IQR 3.76 – 6.10] x 10 9 /L , p<0.001;Median CRP 5.7 [IQR 2.0 – 10.0] vs 12.0 [IQR 6.1 – 22.0] mg/L, p<0.001). Trough polymerase chain reaction (PCR) cycle threshold (Ct) values were significantly higher with Omicron infection (17.6 [IQR 16.3 – 19.3] vs 14.9 [IQR 13.9 – 19.0], p=0.001). The pattern and rate of rise in Ct values was similar between Omicron and Delta. At the time of infection, Omicron infected patients had lower levels of pro-inflammatory cytokines Vaccine breakthrough infections with the Omicron variant had a low concentration of proinflammatory cytokines, chemokines, and growth factors at the acute phase of infection, but a more robust IFN-γ response. Less dysregulated immune cell profiles were also observed, including a lower immature neutrophil cell count in Omicron breakthrough cases Conclusions: Omicron infections resulted in mild vaccine breakthrough illness in the majority of patients. Compared with Delta, Omicron infections were more frequently associated with upper respiratory tract infections, had lower viral loads, lower levels of pro-inflammatory cytokines and less dysregulated immune cell profiles.

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324729

ABSTRACT

Background: Host determinants of severe coronavirus disease 2019 include advanced age, comorbidities and male sex. Virologic factors may also be important in determining clinical outcome and transmission rates, but limited patient-level data is available. Methods: We conducted an observational cohort study at seven public hospitals in Singapore. Clinical and laboratory data were collected and compared between individuals infected with different SARS-CoV-2 clades. Firth’s logistic regression was used to examine the association between SARS-CoV-2 clade and development of hypoxia, and quasi-Poisson regression to compare transmission rates. Plasma samples were tested for immune mediator levels and the kinetics of viral replication in cell culture were compared. Findings: 319 patients with PCR-confirmed SARS-CoV-2 infection had clinical and virologic data available for analysis. 29 (9%) were infected with clade S, 90 (28%) with clade L/V, 96 (30%) with clade G (containing D614G variant), and 104 (33%) with other clades ‘O’ were assigned to lineage B.6. After adjusting for age and other covariates, infections with clade S (adjusted odds ratio (aOR) 0·030 (95% confidence intervals (CI): 0·0002-0·29)) or clade O (B·6) (aOR 0·26 (95% CI 0·064-0·93)) were associated with lower odds of developing hypoxia requiring supplemental oxygen compared with clade L/V. Patients infected with clade L/V had more pronounced systemic inflammation with higher concentrations of pro-inflammatory cytokines, chemokines and growth factors. No significant difference in the severity of clade G infections was observed (aOR 0·95 (95% CI: 0·35-2·52). Though viral loads were significantly higher, there was no evidence of increased transmissibility of clade G, and replicative fitness in cell culture was similar for all clades. Interpretation: Infection with clades L/V was associated with increased severity and more systemic release of pro-inflammatory cytokines. Infection with clade G was not associated with changes in severity, and despite higher viral loads there was no evidence of increased transmissibility.Funding Statement: This study was funded by grants from the Singapore National Medical Research Council (COVID19RF- 001, COVID19RF2-0001, COVID19RF-007, and COVID19RF-60) and Biomedical Research Council (project number H20/04/g1/006).Declaration of Interests: No conflicts of interest declared.Ethics Approval Statement: The epidemiological investigation was conducted under the Infectious Diseases Act (Singapore). Study protocols were approved by ethics committees of the National Healthcare Group and SingHealth. Written informed consent was obtained from participants for clinical data and biological sample collection as part of the PROTECT study (2012/00917;2018/3045). A waiver of informed consent for retrospective data collection only was granted for individuals admitted to the National Centre of Infectious Diseases (2020/01122). Healthy donor samples were collected under study numbers 2017/2806 and NUS IRB 04-140.

12.
EMBO Mol Med ; 14(3): e15227, 2022 03 07.
Article in English | MEDLINE | ID: covidwho-1643965

ABSTRACT

The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor-binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1ß and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.


Subject(s)
COVID-19 , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2
13.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296939

ABSTRACT

Efficient COVID-19 vaccines have been developed in record time. Here, we present findings from a comprehensive and integrated analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 mRNA vaccine. Two vaccine doses induced high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of delta variant was less efficient than that of the Wuhan strain. Age stratified analyses identified a group of low antibody responders where individuals ≥ 60 years were overrepresented. Waning of the antibody and cellular responses was observed in 30% of the vaccinees after six months. However, age did not influence the waning of these responses. Taken together, while individuals ≥ 60 years old took longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at six months post-vaccination. However, the higher proportion of older individuals in the group of antibody low responders and the lower antibody reactivity the Delta variant call for a booster immunization to increase immune responses and protection.

14.
Front Immunol ; 12: 710217, 2021.
Article in English | MEDLINE | ID: covidwho-1555700

ABSTRACT

Severe SARS-CoV-2 infection can trigger uncontrolled innate and adaptive immune responses, which are commonly associated with lymphopenia and increased neutrophil counts. However, whether the immune abnormalities observed in mild to severely infected patients persist into convalescence remains unclear. Herein, comparisons were drawn between the immune responses of COVID-19 infected and convalescent adults. Strikingly, survivors of severe COVID-19 had decreased proportions of NKT and Vδ2 T cells, and increased proportions of low-density neutrophils, IgA+/CD86+/CD123+ non-classical monocytes and hyperactivated HLADR+CD38+ CD8+ T cells, and elevated levels of pro-inflammatory cytokines such as hepatocyte growth factor and vascular endothelial growth factor A, long after virus clearance. Our study suggests potential immune correlates of "long COVID-19", and defines key cells and cytokines that delineate true and quasi-convalescent states.


Subject(s)
COVID-19/immunology , SARS-CoV-2/immunology , Adult , Aged , COVID-19/complications , Cohort Studies , Convalescence , Female , Humans , Male , Middle Aged
15.
J Clin Immunol ; 42(2): 214-229, 2022 02.
Article in English | MEDLINE | ID: covidwho-1544509

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that have become dominant as the pandemic progresses bear the ORF8 mutation together with multiple spike mutations. A 382-nucleotide deletion (Δ382) in the ORF7b and ORF8 regions has been associated with milder disease phenotype and less systemic inflammation in COVID-19 patients. However, its impact on host immunity against SARS-CoV-2 remains undefined. Here, RNA-sequencing was performed to elucidate whole blood transcriptomic profiles and identify contrasting immune signatures between patients infected with either wildtype or Δ382 SARS-CoV-2 variant. Interestingly, the immune landscape of Δ382 SARS-CoV-2 infected patients featured an increased adaptive immune response, evidenced by enrichment of genes related to T cell functionality, a more robust SARS-CoV-2-specific T cell immunity, as well as a more rapid antibody response. At the molecular level, eukaryotic initiation factor 2 signaling was found to be upregulated in patients bearing Δ382, and its associated genes were correlated with systemic levels of T cell-associated and pro-inflammatory cytokines. This study provides more in-depth insight into the host-pathogen interactions of ORF8 with great promise as a therapeutic target to combat SARS-CoV-2 infection.


Subject(s)
Adaptive Immunity/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Cytokines/immunology , Host-Pathogen Interactions/immunology , Humans , Inflammation/immunology , Mutation/immunology , Pandemics/prevention & control , T-Lymphocytes/immunology
16.
Clin Infect Dis ; 73(9): e2932-e2942, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1500989

ABSTRACT

BACKGROUND: Key knowledge gaps remain in the understanding of viral dynamics and immune response of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. METHODS: We evaluated these characteristics and established their association with clinical severity in a prospective observational cohort study of 100 patients with PCR-confirmed SARS-CoV-2 infection (mean age, 46 years; 56% male; 38% with comorbidities). Respiratory samples (n = 74) were collected for viral culture, serum samples for measurement of IgM/IgG levels (n = 30), and plasma samples for levels of inflammatory cytokines and chemokines (n = 81). Disease severity was correlated with results from viral culture, serologic testing, and immune markers. RESULTS: Fifty-seven (57%) patients developed viral pneumonia, of whom 20 (20%) required supplemental oxygen, including 12 (12%) with invasive mechanical ventilation. Viral culture from respiratory samples was positive for 19 of 74 patients (26%). No virus was isolated when the PCR cycle threshold (Ct) value was >30 or >14 days after symptom onset. Seroconversion occurred at a median (IQR) of 12.5 (9-18) days for IgM and 15.0 (12-20) days for IgG; 54/62 patients (87.1%) sampled at day 14 or later seroconverted. Severe infections were associated with earlier seroconversion and higher peak IgM and IgG levels. Levels of IP-10, HGF, IL-6, MCP-1, MIP-1α, IL-12p70, IL-18, VEGF-A, PDGF-BB, and IL-1RA significantly correlated with disease severity. CONCLUSIONS: We found virus viability was associated with lower PCR Ct value in early illness. A stronger antibody response was associated with disease severity. The overactive proinflammatory immune signatures offer targets for host-directed immunotherapy, which should be evaluated in randomized controlled trials.


Subject(s)
COVID-19 , Pneumonia, Viral , Antibodies, Viral , Female , Humans , Immunoglobulin M , Male , Middle Aged , Prospective Studies , SARS-CoV-2 , Seroconversion
17.
NPJ Vaccines ; 6(1): 125, 2021 Oct 25.
Article in English | MEDLINE | ID: covidwho-1483131

ABSTRACT

The rapid spreading of SARS-CoV-2 variants B.1.1.7 originated from the United Kingdom and B.1.351 from South Africa has contributed to the second wave of COVID-19 cases in the respective countries and also around the world. In this study, we employed advanced biochemical and virological methodologies to evaluate the impact of Spike mutations of these strains on the degree of protection afforded by humoral immune responses following natural infection of the ancestral SARS-CoV-2 strain during the early stages of the outbreak. We found that antibody-mediated neutralization activity was partially reduced for B.1.1.7 variant and significantly attenuated for the B.1.351 strain. We also found that mutations outside the receptor-binding domain (RBD) can strongly influence antibody binding and neutralization, cautioning the use of solely RBD mutations in evaluating vaccine efficacy. These findings highlight an urgent need to develop new SARS-CoV-2 vaccines that are not based exclusively on the ancestral SARS-CoV-2 Spike gene sequence.

19.
Front Immunol ; 12: 680188, 2021.
Article in English | MEDLINE | ID: covidwho-1311374

ABSTRACT

A significant proportion of COVID-19 patients will progress to critical illness requiring invasive mechanical ventilation. This accentuates the need for a therapy that can reduce the severity of COVID-19. Clinical trials have shown the effectiveness of remdesivir in shortening recovery time and decreasing progression to respiratory failure and mechanical ventilation. However, some studies have highlighted its lack of efficacy in patients on high-flow oxygen and mechanical ventilation. This study uncovers some underlying immune response differences between responders and non-responders to remdesivir treatment. Immunological analyses revealed an upregulation of tissue repair factors BDNF, PDGF-BB and PIGF-1, as well as an increase in ratio of Th2-associated cytokine IL-4 to Th1-associated cytokine IFN-γ. Serological profiling of IgG subclasses corroborated this observation, with significantly higher magnitude of increase in Th2-associated IgG2 and IgG4 responses. These findings help to identify the mechanisms of immune regulation accompanying successful remdesivir treatment in severe COVID-19 patients.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Cytokines/blood , Hospitalization , SARS-CoV-2/genetics , Adenosine Monophosphate/therapeutic use , Adult , Aged , Alanine/therapeutic use , Antibodies, Viral/blood , Antibodies, Viral/immunology , Becaplermin/blood , Brain-Derived Neurotrophic Factor/blood , COVID-19/blood , COVID-19/immunology , Case-Control Studies , Female , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Membrane Proteins/blood , Middle Aged , Prospective Studies , Spike Glycoprotein, Coronavirus/immunology , Treatment Outcome
20.
STAR Protoc ; 2(3): 100671, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1275774

ABSTRACT

One of the key public health strategies in coronavirus 2019 disease (COVID-19) management is the early detection of infected individuals to limit the transmission. As a result, serological assays have been developed to complement PCR-based assays. Here, we report the development of a flow cytometry-based assay to detect antibodies against full-length SARS-CoV-2 spike protein (S protein) in patients with COVID-19. The assay is time-efficient and sensitive, being able to capture the wider repertoire of antibodies against the S protein. For complete details on the use and execution of this protocol, please refer to Goh et al. (2021).


Subject(s)
Antibodies, Neutralizing/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Flow Cytometry/methods , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Neutralizing/immunology , COVID-19/blood , COVID-19/immunology , COVID-19/virology , Humans
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