New studies have found that people who have tested negative for COVID-19 antibodies, developed T cells instead in a response to their COVID-19 infections.
When the body is infected with a pathogen such as a virus, it mounts a protective response through immune cells and the production of pathogen-specific antibodies. The antibodies remove the viruses before they can infect cells. Cytotoxic T cells kill infected cells via inflammatory mediators to prevent the function of the invading organism. In the case of COVID-19 (SARS-CoV-2) clinical studies, patients have been found to recover from the viral infection without the development of antibodies to the virus. However, they did develop a T-cell response to COVID-19. Therefore, it is believed that people who are asymptomatic or have a mild illness can remove the virus via T cells.
Covid-19 and T Cells
Given the lack of antibody response in some people with mild illness, a potential vaccine must have the capacity to elicit robust T-cell and antibody responses. The duration of antibody responses to COVID-19 is not fully determined. It seems that T cells are a crucial component to immunity, particularly if the antibody response is absent or short-lived. Thus far, observations in small studies indicate that some people mounted T-cell responses to COVID-19, yet no antibodies were detected. Also, people with strong T-cell responses to COVID-19 had either no symptoms or mild illness whether or not they had circulating antibodies to the virus.
Past Exposures and T Cells
Evidence gained to date suggests that T cells developed after exposure to common cold−related coronaviruses can respond to COVID-19. Results from a La Jolla Institute study on stored blood samples showed that the studied T cells responded to the COVID-19 virus. This suggests that an individual’s T cells produced during a common cold infection may be able to respond to infection with the COVID-19 virus effectively.
Moving forward, research aimed at determining how exactly antibody levels compare to virus exposure and how long the antibodies last would help significantly in understanding the COVID-19 immunity process. Also important to know is what components or mixtures of the components are essential for optimal protection against viral infection. These ongoing and future studies can guide the development of effective means to combat COVID-19.
If you would like to further research on the relationship between T cells and COVID-19, check out the high-quality positive COVID-19 samples offered by HemaCare.
Scientists focus on how immune system T cells fight coronavirus in absence of antibodies. (2020). Retrieved 5 August 2020, from https://www.reuters.com/article/us-health-coronavirus-immunesystem/scientists-focus-on-how-immune-system-t-cells-fight-coronavirus-in-absence-of-antibodies-idUSKBN24B1D8