A study on how T cells, a critical component of the immune system, respond to fight Covid-19 infection in vaccinated individuals will start here next month.
T cells are a type of white blood cell that work together with antibodies to eradicate the Sars-CoV-2 virus, which causes Covid-19.
Local biotechnology firm ImmunoScape is working with two vaccine companies to recruit more than 70 individuals, who are set to be vaccinated, for its study here.
The Straits Times has learnt that one of the companies is Arcturus Therapeutics, the American pharmaceutical company working with Duke-NUS Medical School scientists to develop Singapore's own Covid-19 vaccine. The other company is based in Europe.
ImmunoScape is looking to obtain about 250 blood samples from the recruited individuals, with each person providing samples before and after vaccination. Samples will also be collected at several points after vaccination. These samples will be obtained both locally and from around the world.
The number of T cells produced in response to the vaccine and how long they remain in the body will then be measured over time.
Dr Alessandra Nardin, co-founder and chief operating officer of ImmunoScape, said: "The information from our studies will complement data on antibody response and help us understand whether the immune response induced by vaccines may be effective against new variants."
ImmunoScape, which was spun off in 2017 from the Agency for Science, Technology and Research, or A*Star, was also involved in a United States-based laboratory study which showed that T cells induced by the original Covid-19 strain are able to react against three of the new virus variants causing most concern.
The findings of this variant study, released on March 30, showed that the T cells of patients who were infected with the original virus were able to fully recognise the B117 strain first detected in Britain, the P1 variant first identified in Brazil, and the B1351 variant discovered in South Africa.
Viruses induce the production of antibodies - Y-shaped proteins that bind to the surface of a virus and thus hinder its entry into human cells. If the right antibodies are present in sufficient amounts before an individual is exposed to a virus - because they are generated by vaccination, for instance - they may be able to prevent viral infection altogether.
Viral infection also results in the activation and expansion of T cells, which recognise and kill infected cells where the virus is replicating, and boost antibody production.
This research was a collaboration among ImmunoScape and the National Institute of Allergy and Infectious Diseases (Niaid), the Johns Hopkins University School of Medicine and the Johns Hopkins Bloomberg School of Public Health in the US.
The researchers analysed blood from 30 people who had recovered from Covid-19 before the emergence of the new, more contagious variants. They identified T cells active against multiple protein fragments from the virus, and looked at how these T cells fared against the three variants.
A total of 45 different mutations on different proteins of the Sars-CoV-2 virus, including the spike protein, have been identified in the three variants by researchers worldwide.
The team from ImmunoScape and Niaid found that virtually all the protein fragments that were recognised by the T cells were unaffected by the mutations. This would suggest that T cell protection against the variants may remain intact.
Dr Michael Fehlings, ImmunoScape's co-founder and vice-president of operations and development, said: "Our studies will highlight the importance of finally mapping which parts of the virus are recognised by T cells after infection or vaccination. But larger studies against the variants will still be needed to assess protection."
