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360 Dx - Eurofins Viracor Test Measures T-Cell Response to Determine COVID-19 Immunity

NEW YORK – While vaccines for SARS-CoV-2 have rolled out at home and abroad, there is still uncertainty about their long-term effectiveness against the virus, and questions linger about whether a booster shot will be necessary and how often individuals will need to get vaccinated to remain protected against the virus.

Against this backdrop Eurofins Viracor has developed a test that looks at the reactivity of live T cells to help measure patients' immunity after getting vaccinated, joining the ranks of other companies, such as Oxford Immunotec and Adaptive Biotechnologies, to help answer questions about individuals' immune response to the coronavirus.

Eurofins Viracor's test, called the InSight T Cell Immunity Test, is a flow cytometry and intracellular cytokine staining test that looks at the reactivity of live C4+ and CD8+ T cells collected directly from whole blood to the SARS-CoV-2 spike and nucleocapsid proteins to measure a patient's cytokine response and determine levels of immunity.

The test measures three cytokines — interferon-gamma, interleukin-2, and TNF alpha — which indicate an immune response to SARS-CoV-2, said Eurofins Clinical Diagnostics CSO Steve Kleiboeker. Cytokines are the markers of immune response in vaccinated and recovered people, and if T cells produce one or a combination of the cytokines, that's "a demonstration of specific immunity," he said.

Eurofins' test provides "an objective assessment of whether a patient has an immune response to SARS-CoV-2," he added, with results that give clinicians a summary statement of whether immunity was detected, as well as details about spike and nucleocapsid reactivity, and cytokine levels and responses in a patient's blood.

Using four different sample aliquots, the cells are individually stimulated by spike and nucleocapsid peptide pools to measure intracellular cytokine responses and compared to negative controls of blood samples, Kleiboeker said. The cells are stained with a fluorescent dye that recognizes the three cytokines, he said. The value of the stimulated sample divided by the negative control is called the stimulation index, which is included in the lab report for the clinician and provides more detailed information about the immune response.


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