By understanding how some people naturally resist Covid infection, despite clearly being exposed to the virus, could lead to better next generation vaccines
Scientists at University College London say that vaccines should aim to induce an immune response against ‘replication proteins’, essential for the very earliest stages of the viral cycle, concludes new research
By designing vaccines that activate immune memory cells, known as T cells, to attack infected cells expressing this part of the virus’s internal machinery, it may be possible to eliminate SARS-CoV-2 at the very outset, thereby helping stop its spread.
This approach could complement currently licensed Covid-19 vaccines in the UK, which only trigger immune responses to the spike protein that protrudes from the outside of the virus.
Researchers say the discovery, published in Nature, could lead to the creation of a pan-coronaviruses vaccine, that not only protects against SARS-CoV-2 and its variants, but also against coronaviruses that cause common colds, and to new emerging animal coronaviruses.
Senior author Professor Mala Maini (UCL Infection & Immunity) said: “Our research shows that individuals who naturally resisted detectable SARS-CoV-2 infection generated memory T cells that target infected cells expressing the replication proteins, part of the virus’s internal machinery.
“These proteins – required for the earliest stage of the virus’s life cycle, as soon as it enters a cell – are common to all coronaviruses and remain ‘highly conserved’, so are unlikely to change or mutate.
“A vaccine that can induce T cells to recognise and target infected cells expressing these proteins, essential to the virus’s success, would be more effective at eliminating early SARS-CoV-2, and may have the added benefit that they also recognise other coronaviruses that currently infect humans or that could in the future.”
Researchers say next generation vaccines could be developed to induce both memory T cells to target replication proteins and antibodies to target the spike protein.
Professor Maini added: “T cells recognising the virus’ replication machinery would provide an additional layer of protection to that provided by the spike-focused immunity that is generated by the already highly efficacious current vaccines.
“This dual-action vaccine would provide more flexibility against mutations, and because T cells can be incredibly long-lived, could also provide longer-lasting immunity. By expanding pre-existing T cells, such vaccines could help to stop the virus in its tracks at a very early stage.”