Publications by authors named "Neophytos Kouphou"
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels can be used to assess humoral immune responses following SARS-CoV-2 infection or vaccination, and may predict risk of future infection. Higher levels of SARS-CoV-2 anti-Spike antibodies are known to be associated with increased protection against future SARS-CoV-2 infection. However, variation in antibody levels and risk factors for lower antibody levels following each round of SARS-CoV-2 vaccination have not been explored across a wide range of socio-demographic, SARS-CoV-2 infection and vaccination, and health factors within population-based cohorts.
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- COVID-19 severity is influenced by various factors such as age and obesity, but the exact mechanisms behind these risks remain unclear.
- A meta-analysis involving 1,471 participants examined the relationship between genetic and phenotypic factors and the expression of ACE2 in adipose tissue, which is critical for SARS-CoV-2 entry into cells.
- Findings revealed that lower ACE2 expression is linked to poorer cardio-metabolic health, such as type 2 diabetes and obesity, suggesting that reduced ACE2 may play a role in worsening COVID-19 outcomes among individuals with these health issues.
COVID-19 vaccine design and vaccination rollout need to take into account a detailed understanding of antibody durability and cross-neutralizing potential against SARS-CoV-2 and emerging variants of concern (VOCs). Analyses of convalescent sera provide unique insights into antibody longevity and cross-neutralizing activity induced by variant spike proteins, which are putative vaccine candidates. Using sera from 38 individuals infected in wave 1, we show that cross-neutralizing activity can be detected up to 305 days pos onset of symptoms, although sera were less potent against B.
View Article and Find Full Text PDFAs SARS-CoV-2 variants continue to emerge globally, a major challenge for COVID-19 vaccination is the generation of a durable antibody response with cross-neutralizing activity against both current and newly emerging viral variants. Cross-neutralizing activity against major variants of concern (B.1.
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- The interaction between the SARS-CoV-2 Spike protein's receptor binding domain (RBD) and the ACE2 receptor on host cells is crucial for the virus to enter cells and is a major target for neutralizing antibodies.
- Researchers have identified over 100 monoclonal antibodies from infected individuals that target epitopes on RBD, the N-terminal domain (NTD), and the S2 subunits of the Spike protein, with about 45% showing neutralizing ability.
- Mutations in the Spike protein, particularly in the B.1.1.7 variant, can lead to resistance against NTD-specific neutralizing antibodies, highlighting the importance of considering these subdominant epitopes in studying viral variants.
During the first wave of the global COVID-19 pandemic the clinical utility and indications for SARS-CoV-2 serological testing were not clearly defined. The urgency to deploy serological assays required rapid evaluation of their performance characteristics. We undertook an internal validation of a CE marked lateral flow immunoassay (LFIA) (SureScreen Diagnostics) using serum from SARS-CoV-2 RNA positive individuals and pre-pandemic samples.
View Article and Find Full Text PDFThe interaction of the SARS-CoV-2 Spike receptor binding domain (RBD) with the ACE2 receptor on host cells is essential for viral entry. RBD is the dominant target for neutralizing antibodies and several neutralizing epitopes on RBD have been molecularly characterized. Analysis of circulating SARS-CoV-2 variants has revealed mutations arising in the RBD, the N-terminal domain (NTD) and S2 subunits of Spike.
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- Antibody responses to SARS-CoV-2 usually appear in most infected individuals within 10-15 days after symptoms start, but it's unclear how long they last or if they protect against reinfection.
- The study analyzed serum samples from 65 confirmed cases over 94 days and found that over 95% of individuals developed various antibody types, with neutralizing antibodies detected after 8 days post-symptom onset.
- Results indicated that while some individuals retained high neutralizing antibody levels for more than 60 days, others experienced a significant decline, suggesting that booster vaccinations may be necessary for sustained protection against COVID-19.
Article Synopsis
- * A study examined 431 participants from the TwinsUK cohort, finding a seroprevalence rate of 12%, with 19% of seropositive individuals being fully asymptomatic and 27% asymptomatic for key COVID-19 symptoms.
- * Anosmia was identified as the most specific symptom for a positive antibody response, with a specificity rate of 95%, while using a symptom tracking app, 52% of those predicted to have COVID-19 were found to be seropositive.
Comparative assessment of multiple COVID-19 serological technologies supports continued evaluation of point-of-care lateral flow assays in hospital and community healthcare settings.
PLoS Pathog
September 2020
There is a clear requirement for an accurate SARS-CoV-2 antibody test, both as a complement to existing diagnostic capabilities and for determining community seroprevalence. We therefore evaluated the performance of a variety of antibody testing technologies and their potential use as diagnostic tools. Highly specific in-house ELISAs were developed for the detection of anti-spike (S), -receptor binding domain (RBD) and -nucleocapsid (N) antibodies and used for the cross-comparison of ten commercial serological assays-a chemiluminescence-based platform, two ELISAs and seven colloidal gold lateral flow immunoassays (LFIAs)-on an identical panel of 110 SARS-CoV-2-positive samples and 50 pre-pandemic negatives.
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