SCIENTISTS SEEK REASON HOW T CELLS BATTLE COVID-19 SANS ANTIBODIES

As scientists question whether the presence, or absence, of antibodies to the novel coronavirus can reliably determine immunity, some are looking to a different component of the immune system, known as T cells, for their role in protecting people in the pandemic, Deena Beasley wrote for Reuters late on Friday, July 10, 2020.

Recent studies show that some recovered patients who tested negative for coronavirus antibodies did develop T cells in response to their COVID-19 infection. While the studies are small and have yet to be reviewed by outside experts, some scientists now say that people who experience a mild illness, or no symptoms at all, from the new coronavirus, may be eliminating the infection through this T cell response.

The findings add to the evidence that an effective COVID-19 vaccine will need to prompt T cells to work in addition to producing antibodies, and may have implications for several treatments in development. They may also shed light on how immunity to new exposure to infection could work.

“There is mounting evidence that people exposed to the virus have a transient (short-lived) antibody response, or have a T cell response in spite of a minor or absent antibody response,” Dr. Alessandro Sette, professor and member of the La Jolla Institute’s Infectious Disease and Vaccine Center in California, told Reuters. When a virus gets past the body’s initial defenses - which include infection-fighting white blood cells - a more specific “adaptive” response kicks in and triggers production of cells that target the invader. These include antibodies that can recognize a virus and lock onto it, preventing its entry into a person’s cells, as well as T cells that can kill both invaders and the cells they have infected.