Within the medical field, it is understood that antibodies are integral to the immune system, or more specifically, to kill viruses. However, antibodies alone are an ineffective defense mechanism against the virus causing the COVID-19 pandemic, SARS-CoV-2, according to an analysis done by Gladstone Institute’s scientist Dr. Nadia Roan published in Cell Reports Medicine. Further into her research, Dr. Roan noticed that T cells, which kill infected cells and activate immune cells, were the most responsive against the virus. But in what way?
T cells are capable of remembering viruses or fragments of viruses they previously encountered. A National Institute of Health article references a study done at the La Jolla Institute between March 2015 and March 2018 which looked at blood samples to determine T cell’s responses against SARS-CoV-2. Specifically, the study looked at peptides with 15 amino acids from SARS-CoV-2, where they found that 142 fragments of SARS-CoV-2 interacted with T cells. Out of these fragments, 40 were precisely recognized by T cells because some of the common cold coronavirus fragments and SARS-CoV-2 fragments match. According to the same National Institute of Health, 20% to 50% of people who never encountered SARS-CoV-2 before had their T cells respond to the virus.
Despite these results, T cells don’t provide full immunity against SARS-CoV-2, and Medical News Today prefaces that there needs to be more data and information about the long term effects on T cell and even B cell responses in terms of immunity against SARS-CoV-2. Fortunately, the article also states that Dr. James Hindley from Indoor Biotechnologies has recently been working on a straightforward test for labs to “screen T cell responses to SARS-CoV-2,” which could help determine more accurate results of T cell defense.
While the aforementioned study is helpful towards explaining resilience of those who have dealt with various forms of coronavirus, it is important to consider how T cells react to the virus based on as many case studies as possible. A study published in the journal Cell looked at 206 people’s immune systems based on whether they previously encountered SARS-CoV-2 or not, such as: people infected or previously infected with SARS-CoV-2, family members of infected people, and healthy participants who donated blood, either during or after the pandemic. Almost all of the individuals who recovered from SARS-CoV-2, whether it be severe or mild, had T cells recognize fragments of the virus, which was expected. However, the most surprising results occurred when the researchers experimented with whether the T cells within a blood sample of a person who hadn’t previously encountered SARS-CoV-2 would respond to the virus: “In 28% of those….the researchers detected T cells that reacted to SARS-CoV-2.”
Based on the results of these studies, researchers have thought long and hard about how these results could impact potential vaccines against SARS-CoV-2: Dr. Roan suggests that any vaccines for SARS-CoV-2 should look into generating “elicit long-lived and multi-functional T cells against SARS-CoV-2.”
References
“Antibodies Fight off the New Coronavirus, but What Do T Cells Do?” Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/antibodies-fight-off-the-new-coronavirus-but-what-do-t-cells-do.
“Even Mild COVID-19 May Produce Long Lasting Immunity.” Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/even-mild-covid-19-may-produce-long-lasting-immunity.
“Immune Cells for Common Cold May Recognize SARS-CoV-2.” National Institutes of Health, U.S. Department of Health and Human Services, 18 Aug. 2020, www.nih.gov/news-events/nih-research-matters/immune-cells-common-cold-may-recognize-sars-cov-2.
Langelier, Julie. “Finding Clues to a Successful Immune Response in the T Cells of COVID-19 Patients.” Medical Xpress - Medical Research Advances and Health News, Medical Xpress, 21 Aug. 2020, medicalxpress.com/news/2020-08-clues-successful-immune-response-cells.html.
Written by Keya Mann
Edited by Lucy Ge
Graphics by Karis Kelly
Group advised by Sadia Akbar
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