New research reveals that for optimal results, the vaccine should also activate T cells.
Across the world, hard work is currently underway on coronavirus vaccines. While the development of an infectious disease vaccine normally takes about five to 10 years, efforts are currently underway to get a corona vaccine on the market as soon as possible. More than a hundred vaccines against SARS-Cov-2 are currently in development. Some of these have been developed to the extent that they can be tested on humans. Which vaccine will eventually become the ultimate corona vaccine? A vaccine that ensures the production of antibodies and activates T cells, write researchers at Erasmus MC.
It means that scientists should not only look at which vaccination yields the best antibodies, but also which T cells are activated. The T cell is part of the specific cellular defenses and clears the infection, as it were. “Activating these cells appears to be at least as important as the production of antibodies,” says Erasmus MC Virologist Rory de Vries. If, despite those antibodies, the virus still causes an infection, the T cells are also able to attack the virus.
In the study, the researchers followed ten COVID-19 patients with the most severe disease symptoms. All ten were admitted to the Erasmus University Medical Center and were on respiration. Two of the patients eventually died of the disease. What the research shows is that even the sickest COVID-19 patients produce T cells that help fight the virus. Indeed, a thorough analysis of the immune responses shows that all ten patients produced T cells that attacked the virus. These T cells interacted with antibodies to destroy the virus and stop the infection.
The findings are consistent with a recent US cell study that showed people with moderate COVID-19 symptoms also produced T cells. In both studies, these T cells focus on the so-called ‘spike protein’ found on the outside of the virus. This protein is critical for SARS-CoV-2 as it helps the virus invade human cells. Many vaccines currently under development are aimed at enabling the immune system to recognize and attack this protein. The new study provides more evidence that the spike protein is indeed a promising target. “It’s good news for those working on a vaccine that targets these spikes,” said researcher Daniela Weiskopf.
A vaccine that targets these spikes is the promising British corona vaccine ChAdOx1 nCoV-19. The vaccine is made from a weakened version of a cold virus that affects chimpanzees. This virus is genetically modified, preventing it from growing in humans. The vaccine aims to ensure that the most potent weapon of the virus – the ‘spikes’ – targets the virus. This is done by stimulating the immune system to produce antibodies that bind to these spikes, so that the immune system gets a grip on the virus and can destroy it.
According to De Vries, it is important that ongoing studies into a corona vaccine also examine whether vaccination leads to the activation of T cells. This is not always happening now. “Most vaccines target only one viral protein and the production of antibodies,” says De Vries. “But our studies show that multiple proteins lead to an activation of the T cells. Multi-protein vaccines that activate the T cells may be more effective. These T cells may be crucial in long-term immunity. ”
The research also shows that both Dutch and American patients show similar reactions to the virus. “This is essential to understanding how the immune system fights the virus,” explains researcher Alessandro Sette. “You want vaccine development to be based on observations from quite diverse environments to ensure that the results are generally applicable. So to truly understand a global pandemic, our approach must also be global. It is important to study immune responses in people with different genetic backgrounds who live in different environments. ”
Although we do have to be patient before the ultimate corona vaccine appears on the market, major steps are being taken. And that is also urgently needed. In the meantime, more than half a million people worldwide have died due to COVID-19. The number of confirmed infections has also broken through the 10 million mark. This makes it painfully clear that the virus is still spreading around – and faster.
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