ArticleInternational journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases2021
Pre-existing T-cell immunity to SARS-CoV-2 in unexposed healthy controls in Ecuador, as detected with a COVID-19 Interferon-Gamma Release Assay.
Article in International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 35 papers.
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35 citing papers in PubMed, 51 citations in OpenAlex.
- Immune response dynamics to SARS-CoV-2 in the Albanian population: A study on T-cell and antibody interactions during the transition from pandemic to endemic phase.Infectious diseases & immunity · 2025Article
- Comparison of different T cell assays for the retrospective determination of SARS-CoV-2 infection.The Journal of general virology · 2024Article
- Neutralizing immunity against coronaviruses in Tanzanian health care workers.Scientific reports · 2024Article
- Pre-existing cell populations with cytotoxic activity against SARS-CoV-2 in people with HIV and normal CD4/CD8 ratio previously unexposed to the virus.Frontiers in immunology · 2024Article
- Performance Evaluation of Three Antibody Binding Assays, a Neutralizing Antibody Assay, and an Interferon-Gamma Release Assay for SARS-CoV-2 According to Vaccine Type in Vaccinated Group.Diagnostics (Basel, Switzerland) · 2023Article
- Potential use of endemic human coronaviruses to stimulate immunity against pathogenic SARS-CoV-2 and its variants.The Libyan journal of medicine · 2023Article
- Humoral and T cell responses to SARS-CoV-2 reveal insights into immunity during the early pandemic period in Pakistan.BMC infectious diseases · 2023Article
- Exploring the vaccine-induced immunity against severe acute respiratory syndrome coronavirus 2 in healthcare workers.Scientific reports · 2023Article
- Comparative analysis between STANDARD-E Covi-FERON ELISA with pre-existing IFN-γ release assays and determination of the optimum cutoff value for assessment of T-Cell response to SARS-CoV-2.Journal of clinical laboratory analysis · 2023Article
- Article
- A comprehensive study of Ecuadorian adult patients with a mild and moderate presentation of COViD-19.PloS one · 2023Article
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- Accuracy of QuantiFERON SARS-CoV-2 research use only assay and characterization of the CD4International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases · 2022Article
- Lasting SARS-CoV-2 specific IgG Antibody response in health care workers from Venezuela, 6 months after vaccination with Sputnik V.International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases · 2022Article
- Review
- An adjusted ELISpot-based immunoassay for evaluation of SARS-CoV-2-specific T-cell responses.Biosafety and health · 2022Article
- The presence of serum anti-SARS-CoV-2 IgA appears to protect primary health care workers from COVID-19.European journal of immunology · 2022Article
- Article
- A Pilot Study for the Evaluation of an Interferon Gamma Release Assay (IGRA) To Measure T-Cell Immune Responses after SARS-CoV-2 Infection or Vaccination in a Unique Cloistered Cohort.Journal of clinical microbiology · 2022Article
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Authors and funding
7 authors at 3 institutions in 2 countries.
Funding
Abstract
backgroundStudies of T-cell immune responses against SARS-CoV-2 are important in understanding the immune status of individuals or populations. Here, we use a simple, cheap, and rapid whole blood stimulation assay - an Interferon-Gamma Release Assay (IGRA) - to study T-cell immunity to SARS-CoV-2 in convalescent COVID-19 patients and in unexposed healthy contacts from Quito, Ecuador.
methodsInterferon-gamma (INF-γ) production was measured in the heparinized blood of convalescent and unexposed subjects after stimulation for 24 h with the SARS-CoV-2 Spike S1 protein, the Receptor Binding Domain (RBD) protein or the Nucleocapsid (NP) protein, respectively. The presence of IgG-RBD protein antibodies in both study groups was determined with an "in-house" ELISA.
resultsAs measured with INF-γ production, 80% of the convalescent COVID-19 patients, all IgG-RBD seropositive, had a strong T-cell response. However, unexpectedly, 44% of unexposed healthy controls, all IgG-RBD seronegative, had a strong virus-specific T-cell response with the COVID-19 IGRA, probably because of prior exposure to common cold-causing coronaviruses or other viral or microbial antigens. CONCLUSION AND DISCUSSION: The high percentage of unexposed healthy subjects with a pre-existing immunity suggests that a part of the Ecuadorian population is likely to have SARS-CoV-2 reactive T-cells. Given that the IGRA technique is simple and can be easily scaled up for investigations where high numbers of patients are needed, this COVID-19 IGRA may serve to determine if the T-cell only response represents protective immunity to SARS-CoV-2 infection in a population-based study.
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