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EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-305637


Background : Angiotensin I converting enzyme 2 (ACE2) is a receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and differences in its expression may affect susceptibility to infection. Methods : We performed a genome-wide expression quantitative trait loci (eQTL) analysis using hepatitis C virus-infected liver tissue from 190 individuals. Results : We discovered that polymorphism in a type III interferon gene ( IFNL4 ), which eliminates IFN-λ4 production, is associated with a two-fold increase in ACE2 RNA expression. Conversely, among genes negatively correlated with ACE2 expression, IFN-signalling pathways were highly enriched and ACE2 was downregulated after IFN-α treatment. Negative correlation was also found in the gastrointestinal tract where inflammation driven IFN-stimulated genes were negatively correlated with ACE2 expression and in lung tissue from a murine model of SARS-CoV-1 infection suggesting conserved regulation of ACE2 across tissue and species. Conclusions : We conclude that ACE2 is likely a negatively-regulated interferon-stimulated gene (ISG) and carriage of IFNL4 gene alleles which modulates ISGs expression in viral infection may play a role in SARS-CoV-2 pathogenesis with implications for therapeutic interventions.

Nat Commun ; 12(1): 2055, 2021 04 06.
Article in English | MEDLINE | ID: covidwho-1171493


Identification of protective T cell responses against SARS-CoV-2 requires distinguishing people infected with SARS-CoV-2 from those with cross-reactive immunity to other coronaviruses. Here we show a range of T cell assays that differentially capture immune function to characterise SARS-CoV-2 responses. Strong ex vivo ELISpot and proliferation responses to multiple antigens (including M, NP and ORF3) are found in 168 PCR-confirmed SARS-CoV-2 infected volunteers, but are rare in 119 uninfected volunteers. Highly exposed seronegative healthcare workers with recent COVID-19-compatible illness show T cell response patterns characteristic of infection. By contrast, >90% of convalescent or unexposed people show proliferation and cellular lactate responses to spike subunits S1/S2, indicating pre-existing cross-reactive T cell populations. The detection of T cell responses to SARS-CoV-2 is therefore critically dependent on assay and antigen selection. Memory responses to specific non-spike proteins provide a method to distinguish recent infection from pre-existing immunity in exposed populations.

Antiviral Agents/pharmacology , COVID-19/immunology , COVID-19/virology , Cross Reactions/immunology , Immunoassay/methods , SARS-CoV-2/physiology , T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/epidemiology , Cell Proliferation , Cytokines/metabolism , HEK293 Cells , Health Personnel , Humans , Immunoglobulin G/immunology , Immunologic Memory , Interferon-gamma/metabolism , Pandemics , Peptides/metabolism , SARS-CoV-2/drug effects
Euro Surveill ; 25(42)2020 10.
Article in English | MEDLINE | ID: covidwho-886128


BackgroundThe progression and geographical distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the United Kingdom (UK) and elsewhere is unknown because typically only symptomatic individuals are diagnosed. We performed a serological study of blood donors in Scotland in the spring of 2020 to detect neutralising antibodies to SARS-CoV-2 as a marker of past infection and epidemic progression.AimOur objective was to determine if sera from blood bank donors can be used to track the emergence and progression of the SARS-CoV-2 epidemic.MethodsA pseudotyped SARS-CoV-2 virus microneutralisation assay was used to detect neutralising antibodies to SARS-CoV-2. The study comprised samples from 3,500 blood donors collected in Scotland between 17 March and 18 May 2020. Controls were collected from 100 donors in Scotland during 2019.ResultsAll samples collected on 17 March 2020 (n = 500) were negative in the pseudotyped SARS-CoV-2 virus microneutralisation assay. Neutralising antibodies were detected in six of 500 donors from 23 to 26 March. The number of samples containing neutralising antibodies did not significantly rise after 5-6 April until the end of the study on 18 May. We found that infections were concentrated in certain postcodes, indicating that outbreaks of infection were extremely localised. In contrast, other areas remained comparatively untouched by the epidemic.ConclusionAlthough blood donors are not representative of the overall population, we demonstrated that serosurveys of blood banks can serve as a useful tool for tracking the emergence and progression of an epidemic such as the SARS-CoV-2 outbreak.

Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Blood Donors , Coronavirus Infections/epidemiology , Pandemics , Pneumonia, Viral/epidemiology , Population Surveillance , Adult , COVID-19 , Cluster Analysis , Coronavirus Infections/blood , Enzyme-Linked Immunosorbent Assay , Female , Geography, Medical , Humans , Inhibitory Concentration 50 , Male , Models, Immunological , Neutralization Tests , Pneumonia, Viral/blood , Prevalence , SARS-CoV-2 , Scotland/epidemiology , Sensitivity and Specificity , Seroepidemiologic Studies , Urban Population