Role of T cells: understanding exposure and immunity to COVID-19

Role of T cells: understanding exposure and immunity to COVID-19

T cells and the body’s
response to COVID-19

Your immune system stores a record of every germ it has ever encountered—in special cells called B cells and T cells, also known as memory cells. With this memory, your body can recognize and fight off those germs more easily the next time.

Some viruses, like the flu and the common cold, have to be fought off repeatedly because they come in different strains and they change, or mutate, over time.

Why are memory cells important for COVID-19?

T cells are the first responders of the adaptive immune system and activate the antibody response.

When you’re exposed to a virus, T cells are the first to respond. They kill infected cells and then stimulate B cells to produce antibodies, which circulate in the blood to look for remaining traces of the virus and bind to them so T cells can destroy them. This is the process that kicks in when someone is infected with SARS-CoV-2, the virus that causes COVID-19.1,2,3

 

 

Why is the T cell response to COVID-19 important to understand?

Understanding the T cell response can help researchers better predict the course of the disease, learn how best to support patients, and get a clearer picture of how the immune system responds to COVID-19.4

In people with asymptomatic or mild COVID-19, the immune response seems to work in a routine fashion. In cases of severe COVID-19, the immune response is uncoordinated and the body has trouble controlling the disease.5

Studies show that T cell immune responses, which occur before the antibody response, can be detected approximately one week after the onset of COVID-19 symptoms.6,11,12

Why is the T cell response to COVID-19 important to understand?

Understanding the T cell response can help researchers better predict the course of the disease, learn how best to support patients, and get a clearer picture of how the immune system responds to COVID-19.4

In people with asymptomatic or mild COVID-19, the immune response seems to work in a routine fashion. In cases of severe COVID-19, the immune response is uncoordinated and the body has trouble controlling the disease.5

T cells and SARS-CoV-2

Adaptive Biotechnologies is part of the global effort to quickly learn more about COVID-19 and find solutions that will help end the pandemic. We believe that T cells are crucial to understanding exposure and immunity to this disease and to solving this enormous puzzle.

Until recently, T cells were notoriously hard to study because doing so requires millions of genetic data points and massive data processing power. At Adaptive, we have the technology to map T cells at that scale—including tracking T cell responses to vaccines that are in development.

Why T‑cells?

A larger window of detection

T cell responses arise earlier than antibodies and last through virus removal into recovery.13

An early sign of immune response

T cells play a critical role in supporting the development of antibodies by B cells and can serve as the first signs of an immune response to SARS-CoV-2 infection.14

Observe past infection

T cells specific to SARS-CoV-2 were observed up to several months after the primary infection.15

Specific and robust

T cells develop responses to various parts of a virus; this makes T cell tests highly specific and robust compared to antibody tests, which might not capture the entire immune response.16,17

Disease severity correlation

Early studies show T cell immune response correlates with disease severity.17

Why T cell testing?

T cell responses arise earlier than antibodies and have been observed up to several months after the primary infection with SARS-CoV-2.15

T cells also develop responses to various parts of a virus; this makes T cell tests highly specific and robust compared to antibody tests, which might not capture the entire immune response.16,17 Early studies also show that the T cell response correlates with disease severity.5

In contrast, antibody tests can detect only a limited number of virus regions. Antibody tests can also potentially miss an immune response to viral mutations such as the newly identified SARS-CoV-2 variants.18

Adaptive is making the T-Detect™ COVID test available at a special price during the current public health emergency so individuals can better understand their exposure or potential protective immunity and so those who test positive for past COVID-19 can work with their doctor to address ongoing health issues and determine appropriate follow-up care.

 

T Detect Patient Action Home

For Patients

The T-Detect COVID test can detect past COVID-19 infections for up to several months.

Learn More
T Detect Home Physicans Action

For Physicians

The T-Detect COVID test can capture past COVID-19 infections that may be missed by serology testing.

Learn More
T Detect Home Employers Action

For Employers

The T-Detect COVID test can help your employees get the answers they need.

Learn More
T Detect Home Researchers Action

For Researchers

The T-Detect COVID test can support your research due to its high sensitivity and specificity.

Learn More

This test has not been FDA cleared or approved but has been authorized for emergency use by FDA under an EUA.

Testing of venous whole blood using K2 EDTA specimens is limited to laboratories designated by Adaptive Biotechnologies Corporation that are certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, and meets the requirements to perform high complexity tests as described in the T-Detect COVID Test Standard Operating Procedure that was reviewed by the FDA under this EUA.

This test has been authorized only for detecting and identifying the presence of an adaptive T-cell immune response to SARS-CoV-2, not for any other viruses or pathogens.

The emergency use of this test is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for detection and/or diagnosis of COVID-19 under Section 564(b)(1) of the Federal Food, Drug and Cosmetic Act, 21 U.S.C. § 360bbb3(b)(1), unless the declaration is terminated or authorization is revoked sooner.

T-Detect™ COVID is not indicated for use in patients under age 18.

References

  1. Hufford MM, et al. Curr Top Microbiol Immunol. 2015;386:423-455. doi:10.1007/82_2014_397.
  2. Oh H-LJ, et al. Emerg Microbes Infect. 2012;1(1):1-6. doi:10.1038/emi.2012.26.
  3. Tang F, et al. J Immunol. 2011;186(12):7264- 7268. doi:10.4049/jimmunol.0903490.
  4. Grifoni A, et al. Cell. 2020;181(7):1489- 1501.e15. doi:10.1016/j.cell.2020.05.015.
  5. Billingsley, A. How Does the Immune System Fight COVID-19? Good Rx. https://www.goodrx.com/blog/how-the-immune-system-fights-covid-19/ Published October 9, 2020. Accessed February 3, 2021.
  6. Gallais F, et al. medRxiv. Published online June 6, 2020. 2020.06.21.20132449; doi:10.1101/2020. 06.21.20132449.
  7. Peng Y, et al. Nat Immunol. 2020;21(11):1336-1345. doi:10.1038/ s41590-020-0782-6.
  8. Snyder TM, et al. medRxiv. Published online September 17, 2020:2020.07.31.20165647. doi:10.1101/ 2020.07.31.20165647.
  9. Subbarao K, et al. Immunity. 2020;52(6):905-909. doi:10.1016/j. immuni.2020.05.004.
  10. Channappanavar R, et al. Immunol Res. 2014;59(1-3):118-128. doi:10.1007/ s12026-014-8534-z.
  11. Cox RJ, et al. Nat Rev Immunol. 2020;20(10):581-582. doi:10.1038/ s41577-020-00436-4.
  12. Tay MZ, et al. Nat Rev Immunol. 2020;20(6):363-374. doi:10.1038/ s41577-020-0311-8.
  13. Sekine T, et al. Cell. 2020;183(1):158-168.e14. doi:10.1016/j.cell.2020.08.017.
  14. Zuo J, et al. Robust SARS-CoV-2-specific T-cell immunity is maintained at 6 months following primary infection. bioRxiv. 2020.
  15. Gutierrez L, et al. Deciphering the TCR Repertoire to Solve the COVID-19 Mystery. Trends Pharmacol Sci. 2020.
  16. Poland GA, et al. SARS-CoV-2 immunity: review and applications to phase 3 vaccine candidates. Lancet. 2020.
  17. Gittelman RM, et al. Diagnosis and tracking of past SARS-CoV-2 infection in a large study of Vo’, Italy through T-cell receptor sequencing. medRxiv. 2020.
  18. Funk CD, et al. Front Pharmacol. 2020;11. doi:10.3389/fphar.2020.00937.