Filenews 30 July 2021
The second dose of coronavirus vaccines should not be omitted. This is because it produces a strong strengthening of the immune system providing protection against a wide range of viruses.
A study by Stanford University School of Medicine on mRNA vaccines concludes this finding.
"Despite their unexpected effectiveness, little is known about how RNA vaccines work," points out Bali Pulendran, professor of Pathology, Microbiology and Nosology at Stanford.
His study, published in the scientific journal Nature, was designed to show what the effects of the vaccine are on a number of immune system parameters.
The researchers analysed blood samples from RNA vaccine vaccinated. Antibodies, immune signalling protein levels, were measured and characterized the expression of each gene in the genome of 242,479 distinct types and status of immune cells.
"The world's attention has recently focused on COVID-19 vaccines, particularly new RNA vaccines," Pulendran said, while noting that "This is the first time that RNA vaccines have been given to humans and we have no idea how they do what they do, to offer 95% protection against COVID-19."
Uncharted area
Traditionally, the main immune basis for approving new vaccines has been their ability to inoculate neutralizing antibodies. That is, personalized proteins created by immune cells called B cells that can attach to a virus and prevent it from infecting our cells.
"Antibodies are easy to measure," Pulendran said. "But the immune system is much more complicated than that. Antibodies in themselves are far from complexity and the potential range of protection from our immune system."
Pulendran and his colleagues evaluated the evolution of all types of immune cells affected by the vaccine in terms of their number, their activation levels, the genes they express and the proteins and metabolites they produce and secrete during vaccination.
A key component of the immune system examined was T cells: they are immune cells that seek and destroy, without clinging to virus particles, instead detect cells in the body's tissues, which bear signs of viral infections, and once they find them, destroy them.
In addition, the innate immune system, a set of first responder cells, is now considered of enormous importance. "It's the sixth sense of the body," Said Pulendran, "whose constituent cells are the first to know the presence of a pathogen. Without distinguishing pathogens, they secrete signalling proteins as an "initial weapon", starting the response of the adaptive immune system, i.e. B and T cells that attack specific species or strains of viruses or bacteria. The adaptive immune system takes a week to take over, but until then, innate immune cells perform the critical task of keeping the initial infections away, "devouring" or 'immunising' harmful substances, indiscriminately, in what seems pathogenic to them.
RNA vaccines work very differently from classic vaccines consisting of living or dead pathogenic microorganisms, individual proteins or carbohydrates that train the immune system from scratch for that pathogen and erase it. RNA vaccines contain genetic recipes to produce the spike protein that SARS-CoV-2 uses to stick to the cells it infects.
At the start of vaccinations, Stanford Medicine selected 56 healthy volunteers and took blood samples at multiple times before and after the first and second shots. The researchers found that the first dose increases antibody levels as expected, but not as much as the second. Similarly, the second dose also does things that the first one doesn't even do.
New category of immune cells
"The second dose provides significant beneficial effects that go well beyond those of the first dose. It causes a multiple increase in antibody levels, an amazing T-cell response, and a dramatically enhanced innate immune response. Unexpectedly, and especially the second dose, causes the mass mobilization of a newly discovered group of first responder cells, which are usually rare and dormant," Pulendran pointed out.
These first-response monocytes, a small subset of monocytes that express high levels of anti-tic genes were identified in another Pulendran study on vaccines. Which found that these cells do not appear during actual infection, but appear with vaccination.
As the professor pointed out, "this specific group of monocytes, which are part of the innate immune system, constituted only 0.01% of blood cells prior to vaccination. But after the second intake of the vaccine, their amount increased 100 times and reached to represent 1% of all blood cells. In addition, their mood became less inflammatory but more intensely anti-active. They seem uniquely capable of providing broad protection against different viral infections.
And the unusual increase in the frequency of these cells, just one day after booster immunisation, is surprising. It is possible that these cells are able to intercept not only the coronae, but also other viruses."
Kari Nadeau, Professor of Paediatrics, Allergy and Isology, Associate Professor of Biomedical Informatics and Data, Burves Katri, researcher Prabu Arunachalam, and Associate Professor of the National Yerkes Research Center in Atlanta, Thomas Hagan, also participated in the study.
