T-cell responses to coronavirus six months after infection, according to a study by the U.K. Coronavirus Immunology Consortium (UK-CIC).
Along with Public Health England and Manchester University NHS Foundation Trust, UK-CIC has identified “robust T-cell responses” to the coronavirus virus six months following infection.
T-cells are a part of the immune system that targets cells that have been invaded by a virus or other kind of pathogen and they aid other antibody-producing cells in the immune system.
Scientists have been studying T-cell responses to the virus that causes Covid-19 to determine how lasting any immune response might be in patients that have been infected by and recovered from Covid-19.
The UK CIC study investigated 100 individuals who had contracted the coronavirus in March and April of 2020 but were not confined in the hospital with the virus. The researchers noted that all 100 individuals had reported either mild or moderate symptoms or were asymptomatic.
Serum samples were gathered monthly to assess antibody levels, and blood samples were done after six months to evaluate the T-cell responses to the virus.
The study mentioned that several analyses were held to determine various aspects of the T-cell response, including the magnitude of response and the response to several proteins from the virus.
“T-cell responses were present in all individuals at six months after SARS-CoV-2 infection,” it said, indicating “that a robust cellular memory against the virus persists for at least six months.”
The team found, however, that “the size of T-cell response differed between individuals, being considerably (50%) higher in people who had experienced symptomatic disease at the time of infection six months previously.” The study has not yet been peer-reviewed.
The study, authored by Dr. Shamez Ladhani, a consultant epidemiologist at Public Health England, pointed out that the results could shed light on how immunity to the coronavirus works and aid in future vaccine strategies.
“Cellular immunity is a complex but potentially very significant piece of the Covid-19 puzzle, and it’s important that more research be done in this area. However, early results show that T-cell responses may outlast the initial antibody response, which could have a significant impact on Covid vaccine development and immunity research.”
The study recommends further research to evaluate whether this immune response can be sustained over the longer term and to analyze how the strength of the cellular immune response is associated with the likelihood of reinfection.
Professor Paul Moss, the U.K. Coronavirus Immunology Consortium lead from the University of Birmingham, explained that more research is important to know if people who had symptoms were safer from reinfection.
“Interestingly, we found that cellular immunity is stronger at this time point in those people who had symptomatic infection compared with asymptomatic cases. We now need more research to find out if symptomatic individuals are better protected against reinfection in the future.”