Boston, Jul 6: Scientists have found a recipe for even more effective and powerful vaccines against the coronavirus and its rapidly emerging variants, based on the way human cells activate the immune system in response to COVID-19 infection.
Researchers from Boston University and the Broad Institute of Harvard University in the US noted that it is the first real look at exactly what types of "red flags" the human body uses to enlist the help of T cells sent out by the immune system to destroy infected cells.
Until now, COVID-19 vaccines have been focused on activating a different type of immune cell, B cells, which are responsible for creating antibodies.
The researchers noted that developing vaccines to activate the other arm of the immune system -- the T cells -- could dramatically increase immunity against coronavirus, and importantly, its variants.
The findings, published in the journal Cell, suggest that current vaccines might lack some important bits of viral material capable of triggering a holistic immune response in the human body.
The researchers performed experiments on human cells infected with coronavirus, isolating and identifying those missing pieces of SARS-CoV-2 proteins inside the lab.
Based on the new information, "companies should reevaluate their vaccine designs," said Mohsan Saeed, a virologist at Boston University, and co-corresponding author of the research paper.
The team, including computational geneticists Pardis Sabeti and Shira Weingarten-Gabbay, hoped to identify fragments of SARS-CoV-2 that activate the immune system's T cells.
From the start of COVID pandemic, scientists have known the identity of 29 proteins produced by SARS-CoV-2 virus in infected cells -- viral fragments that now make up the spike protein in some coronavirus vaccines, such as the Moderna, Pfizer-BioNTech, and Johnson & Johnson preventives.
Spike protein helps the virus to enter and infect the human cells.
Later, scientists discovered another 23 proteins hidden inside the virus' genetic sequence.
However, the function of these additional proteins has been a mystery until now.
The latest findings reveal that 25 per cent of the viral protein fragments that trigger the human immune system to attack a virus come from these hidden viral proteins.
"It is quite remarkable that such a strong immune signature of the virus is coming from regions (of the virus' genetic sequence) that we were blind to," said Weingarten-Gabby, the paper's lead author.
"Our discovery can assist in the development of new vaccines that will mimic more accurately the response of our immune system to the virus," Sabeti added.
T cells not only destroy infected cells but also memorise the virus' flags so that they can launch an attack, stronger and faster, the next time the same or a different variant of the virus appears, the researchers said.
That, they said, is a crucial advantage, because the coronavirus appears to delay the cell's ability to call in immune help.
The researchers said a new vaccine recipe, incorporating some of the newly discovered internal proteins making up the SARS-CoV-2 virus, would be effective in stimulating an immune response capable of tackling the newly emerging coronavirus variants.
Given the speed with which these variants continue to appear around the world, a vaccine that can provide protection against all of them would be a game changer, they added.