International war "epidemic" operation
Science and Technology Daily, Beijing, June 15 (intern reporter Zhang Jiaxin) Building immunity to the new crown virus is essential for controlling the new crown pneumonia pandemic, protecting individuals from serious diseases, and controlling the spread of the virus.
A key question is how long can immunity against the new coronavirus last?
According to the latest article published on the website of "Nature" on the 14th, scientists studied 63 survivors who had been infected with the new crown virus and found that their immunity to the new crown virus still exists 12 months after being infected.
Among them, the immunity of those who have been vaccinated will be further improved, which is about 50 times higher than before.
At present, scientists generally believe that the two main pillars of the antiviral immune response are immune cells called "cytotoxic T cells" and neutralizing antibodies.
The third pillar is the production of helper T cells, which are virus-specific cells that coordinate the immune response.
Crucially, helper T cells are necessary for the production of immune memory, especially to coordinate the emergence of plasma cells.
Plasma cells, also known as effector B cells, are cells in the immune system that secrete large amounts of antibodies.
About 25 years ago, scientists discovered that plasma cells themselves can become memory cells. Even if the virus disappears, it will continue to secrete antiviral antibodies to protect individuals for a long time.
Memory plasma cells can be maintained in the bone marrow for decades, or even a lifetime.
This time, scientists studied whether long-lived memory plasma cells will be produced in the immune response to the new coronavirus.
Researchers are trying to identify memory plasma cells that secrete antibodies in the bone marrow of patients who have recovered from the new coronary pneumonia.
Memory plasma cells for specific pathogenic factors are extremely scarce.
However, the researchers detected memory plasma cells secreting antibodies specific to the spike protein encoded by the new coronavirus in 15 people about 7 months after infection.
Reanalysis after 4 months revealed that there were still 14 subjects whose plasma cell count remained stable.
Further research found that the concentration of neutralizing antibodies remained unchanged for these recovered patients 6 to 12 months after being infected.
The analysis of memory plasma cells in the blood of recovered patients shows that the acute immune response can even last for more than 6 months.
Studies have also shown that by vaccinating 41% of survivors one year later with mRNA vaccines, the immunity of these people can be further improved.
They produced more plasma cells in their bodies, their antibody levels increased, and their immunity was 50 times higher than before vaccination.