HOUSTON, Texas (KTRK) -- A new study suggests memory T cells may protect some people infected with COVID-19 by remembering past human coronavirus infections.
The National Institute of Allergy and Infectious Diseases (NIH) said it may explain why some people are able to overcome the virus without becoming severely ill.
The study published in the Nature journal found SARS-recovered patients had long-lasting memory T cells from a 2003 SARS-CoV outbreak.
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SARS-CoV-2 memory T cells were also found in people with no history of SARS or COVID-19 or contact with SARS/COVID-19 patients.
According to NIH, SARS-CoV-2 belongs to a large family of coronaviruses, including six known to infect humans, four of which are responsible for the common cold.
Each of them produce antibodies and memory T cells that can recognize and respond to the SARS virus.
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Researchers said it's unclear if memory T cells found in patients with COVID-19 are from previous SARS infections that cause the common cold or exposure to other coronavirus strains not yet known.
"T cells are important because they can be a part of our immune response against viruses," said Dr. Prathit Kulkarni, an assistant professor of infectious diseases at the Baylor College of Medicine. "What we don't know yet is exactly what their specific role is in controlling COVID-19. There's a lot of work being done in this area, but suffice to say, there's another component of the immune system along with antibodies that can help control different types of infections and in particular viral infections."