Can people infected with the flu virus fight COVID-19?

Can someone infected with the flu virus fight COVID-19?

At present, the new crown pneumonia epidemic is raging around the world, and all sectors of society are actively responding to it

Recently, scientists in Berlin have made a new discovery: People who have previously been infected with other coronaviruses and have suffered from the common cold will have a certain degree of resistance to the new coronavirus

In medicine, the reaction of antibodies or sensitized lymphocytes with different antigens with the same or similar epitopes is called cross-reaction

Because of the existence of common antigens, the two kinds of cells that stimulate the body to stimulate the body can not only bind to the surface of the corresponding epitope, but the bacteria that stimulates the antibody produced in the body can also bind to the bacteria on the surface of the same epitope B.

• Common antigen, some biological macromolecules of different organisms have the same antigen structure;

• Common epitope, some fragments (polypeptides) of different biological macromolecules have the same epitope;

• Similar epitopes, different biological macromolecules, the spatial conformation of some epitopes are very similar, which can match the complementarity determining region of the same antibody

  
  

The new discoveries of Berlin scientists described in this article are inseparable from the principle of cross-reaction

Researchers from Charité-Universit?tsmedizin Berlin[1], the Berlin Institute for Health Research and the Max Planck Institute for Molecular Genetics have found through their latest research that patients with the common cold have specific Immune cells can help them enhance their immune response to the new coronavirus

In research and experiments, they also found that this "immune cross-reactivity" will slowly decline with age

Last year, researchers at Charetti’s Berlin Medical University and the Max Planck Institute for Molecular Genetics were shocked to discover that some people who were not infected with the new coronavirus actually have immune memory cells that can help them recognize the new coronavirus.

Then they came to this conclusion:

These helper T cells can be produced in people who are not infected with COVID-19 because these people must have been infected with other coronaviruses before; however, those who have been infected with them before

Most viruses are harmless, which means that they will not have a major impact on life; because the structure of these coronaviruses is similar to the current new coronaviruses (especially the spike protein located on the outer surface of the coronavirus and the new coronavirus).

This "cross-reaction" hypothesis has been fully confirmed by scientists through various experiments

However, it is not clear whether these immune cells will affect the follow-up process of the new coronavirus infection, and it is also one of the topics of intense debate in the scientific community

Therefore, people who have been infected with a pandemic coronavirus (that is, a long-existing and widely spreading coronavirus) will experience symptoms when they are infected with a new type of coronavirus

In the current study, the Berlin research team provided evidence to support their previous assumptions about the existence of protection

The quality of the new coronavirus immune response, that is, the strength of the immune response, is related to the number of cross-reactive cells in the body before the new coronavirus infection
.
These T helper cells are particularly effective in recognizing specific regions of the spike protein
.
Because the genetic sequences of the epidemic coronavirus and the new coronavirus are very similar and well preserved, the specific region of this spike protein can be easily identified
.
 

In the current study, the researchers recruited some people who had not been infected with the COVID-19 virus before and performed nucleic acid tests on them regularly to check whether they were infected with the COVID-19 virus
.
Starting in mid-2020, 17 of the nearly 800 participants they recruited have tested positive
.
The researchers immediately conducted a detailed observation and analysis of the immune system of these patients
.

Through analysis, they found that one of the factors that determine whether a person has a certain immune response to the new coronavirus is: the role of T helper cells-if the new coronavirus patient has been infected by other common cold viruses before, then the T helper cells have been Produced, these cells can now play a major immune role in the fight against the new coronavirus
.

The quality of the new coronavirus immune response, that is, the strength of the immune response, is related to the number of cross-reactive cells in the body before the new coronavirus infection
.
These T helper cells are particularly effective in recognizing specific regions of the spike protein
.
Because the genetic sequences of the epidemic coronavirus and the new coronavirus are very similar and well preserved, the specific region of this spike protein can be easily identified
.
 

Dr.
Claudia Giesecke-Thiel, the corresponding author of this paper and the head of the flow cytometry technical service team of the Max Planck Institute of Molecular Genetics, explained: "During infection with other harmless coronaviruses, the immune system will establish a ' Coronavirus' protective universal memory
.

Once infected with this new type of coronavirus, these memory cells will be reactivated and begin to respond to newly invading pathogens
.
This will help accelerate the initial immune response to the new coronavirus, and can inhibit the spread of the virus in the early stages of infection, thereby playing an important and active role in the treatment of the disease
.

This does not mean that people who have been infected with the common cold virus must prevent the new coronavirus infection, but it will not change the current situation of the new coronavirus pandemic
.
There is no doubt that many people have been infected with other coronaviruses before, but they have also been infected with the new type of coronavirus
.
From this perspective, this will not reduce the importance of vaccination
.

Our research results provide an explanation for our observation of patients since the outbreak, and explain to a certain extent why COVID-19 patients are also COVID-19 patients, but the symptoms of infection are very different between individuals
.
 

This further confirms that after vaccination with the new coronavirus vaccine, the resistance and immunity of T cells produced by the cross-reaction of the virus will also be enhanced
.
Just like a natural infection, the vaccine promotes the production of spike proteins in the body of the new coronavirus (including its well-preserved parts) and provides these spike proteins to the immune system
.

We analyzed the immune response of 31 healthy people
.
After vaccination, their immune system response is different from before vaccination
.
The difference before and after vaccination indicates that normal T helper cells need to be vaccinated after vaccination
.

It will gradually activate within two weeks; however, the activation of cross-reactive T helper cells is very rapid and can be activated within a week
.
Of course, this also has a particularly positive effect on the production of antibodies
.
This speeds up the production of antibodies, so after the first vaccination, people can produce antibodies to the remaining spikes
.
This antibody is usually produced after a booster shot
.
" 

Even after vaccination, if a person has previously been infected with other influenza coronaviruses, at least part of the immune memory can be used
.
This explains well why after young people were vaccinated with the new crown vaccine for the first time, the immunity and protection brought by the vaccine were quickly produced
.

Not only that, but its protective effect is also very strong
.
In the second part of the scientists' study, the researchers analyzed the T helper cells of about 570 healthy individuals, and they observed a gradual decline in the immune cross-reactivity of the elderly
.

In fact, in these elderly people, the number of cross-reactive T cells and their ability to bind to pathogens are much weaker than those in young people
.
This decrease in immune cross-reactivity is normal and is caused by age-related changes
.
 

Professor Thiel said: “Infection with the flu-coronavirus is good for young people because it will help them attenuate the damage caused by the new coronavirus
.
Unfortunately, this benefit does not play a big role in the elderly
.
The third dose (Booster) will be able to compensate for this weak immune response and ensure that this high-risk group has sufficient immunity to the new coronavirus
.
" 

Charetti Medical University Berlin has a long tradition and is also the largest university-affiliated teaching hospital in Europe
.
It was established on the outskirts of Berlin in 1710 as a quarantine hospital
.
A century later, the clinic was completely rebuilt and became the medical department of the newly established University of Berlin
.