15th March 2021 Product update: rapidvirology staff writer
CE-Marked Test to Detect T-Cells for COVID-19 Shows Promising Results for FDA-EUA Request
Oxford Immunotec Global PLC has announced that it has released the T-SPOT.COVID test, a CE-marked ELISPOT based test intended for the qualitative detection of a cell-mediated (T cell) immune response to SARS-CoV-2 in human whole blood.
The company has filed an EUA request to the FDA for the test.
Serology does not give the full picture of the adaptive immune response to SARS-CoV-2 infection. Antibodies are not always produced in response to SARS-CoV-2 infection, or may be delayed1,2.
Antibodies can also wane quickly after infection4 and reports show T cells may be more long-lived than the antibody response3. In the absence of an antibody response, the T cell response may be protective from SARS-CoV-2 infection5.
In a clinical study using samples collected in the US, the T-SPOT.COVID test was proven to detect a SARS-CoV-2 cell-mediated (T cell) immune response in PCR positive individuals, even with negative serology test results6.
The T-SPOT.COVID test, therefore, complements results obtained by antibody serology to give a more comprehensive view of an individual’s adaptive immune response to SARS-CoV-2 infection.
The test could also be used, for example, alongside serology tests to support clinical assessment of individuals who present with suspected COVID-19 but are PCR negative.
In the study, the T-SPOT.COVID test had a positive agreement with PCR-results of 96.6% (84/87) in SARS-CoV-2 infected individuals <60 days after first PCR positive result.
At >60 days (with the furthest time point after first positive PCR test result being >240 days) positive agreement remained high at 83.3% (40/48).
The T-SPOT.COVID test detected substantially more people with previous positive PCR results than serology in the cohort, whose positivity rate was lower and declined faster over time.
In an endemic cohort of US individuals selected to be at a relative lower risk of SARS-CoV-2 infection (based on the absence of self-reported symptoms, negative serology results, and no prior history of a positive PCR test result for SARS-CoV-2) the T-SPOT.COVID test had a negative agreement of 98.0% (96/98)6.
The company developed the T-SPOT.COVID test as an evolution of its T-SPOT® Discovery SARS-CoV-2 assay, a research-use-only (RUO) test used to gain insights into the immune response to SARS-CoV-2.
Dr. Peter Wrighton-Smith, CEO of Oxford Immunotec, said, “The T-SPOT® Technology platform is a standardised way of measuring T cells. It has been proven in clinical use for over 18 years with another major infectious disease, tuberculosis, which kills around 1.5 million people every year. Our T-SPOT.COVID test is tailored specifically for the detection and measurement of an individual’s T cell response to SARS-CoV-2 infection. Having the ability to determine an individual’s immune response to SARS-CoV-2 has the potential to support a wide range of needs in our battle against the COVID-19 pandemic.”
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1. Tan W, Lu Y, Zhang J et al. Viral kinetics and antibody responses in patients with COVID-19. medRxiv. 2020 March 26. Preprint. https://doi.org/10.1101/2020.03.24.20042382
2. Altmann DM, Boyton RJ. SARS-CoV-2 T cell immunity: Specificity, function, durability, and role in protection. Sci Immunol. 2020;5:eabd6160
3. Zuo J, Dowell A, Pearce H et al. Robust SARS-CoV-2-specific T-cell immunity is maintained at 6 months following primary infection. bioRxiv. 2020. doi: 10.1101/2020.11.01.362319
4. Ibarrondo FJ, Fulcher JA, Goodman-Meza D et al. Rapid decay of anti-SARS-CoV-2 antibodies in persons with mild Covid-19. N Engl J Med. 2020; 383: 1085-1087
5. Wyllie D, Mulchandani R, Jones HE et al. SARS-CoV-2 Reactive T cell numbers are associated with protection from COVID-19: A prospective cohort study. medRxiv. doi: 10.11012020.11.02.20222778
6. Package Insert PI-T-SPOT.COVID-IVD-US v3 T-SPOT-COVID-US-PI-v3-1.pdf
Date Published: 15th March 2021
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Note: This content has been edited by a rapidvirology.com staff writer for style and content.
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