Recently, the UK announced the results of the "Coronavirus Implantation Human Challenge Trial". Agencies such as the UK government's vaccine task force recruited 36 young people, none of whom had been vaccinated against the new crown and were in good health. Injecting the new coronavirus into the noses of these young people, it was found that only half of the 36 healthy young people who also inhaled the new coronavirus were infected, and the other half were not.
The purpose of this study is to understand – why do people have natural resistance to viruses?
In order to ensure the safety of the subjects, the subjects were selected for a group of healthy, immunocompetent young people, aged 18 to 29 years.
The trial was conducted at Royal Free Hospital in London and the process was rigorously designed: each participant had a screening period of two to three months, which ensured that the young people were in a health condition and had no underlying medical conditions. After the virus was injected, the researchers took daily samples from the throat and nose of the subjects to detect the concentration of the virus; And blood is drawn to test for antibodies in the serum.
Test results announced!
Category I: 17 without infection at all
The virus was not detected in the throats of these people; There are also no antibodies in the serum.
It's like surrendering without a fight. The immunity of such people is superior, the body is like a lotus leaf, and it will not stain if you sprinkle water on it; The virus is delivered to the nose and cannot be infected.
The second category: asymptomatic infection, 1
One participant had no virus detected in their throat; However, antibodies were detected in serum; He has no symptoms of his own.
It's like a battle without gunsmoke - victory is achieved in the end, and the immunity of such people is also great.
Category III: Infected with the virus, 18 people
These people have mild or moderate symptoms; There are antibodies in the serum; Elevated inflammatory response protein (CRP) – helps release inflammatory factors in the body.
The situation is like there is a fight, there is gunsmoke. The end result was that the virus was cleared and victorious, but at the cost (inflammatory response) and immunity was acceptable.
Analysis of the third group of people - the infected
On the 2nd day after the virus was injected, the researchers detected the virus for the first time in the throats of 18 infected young people; On day 5, the viral load in the throat peaks.
The virus was detected in the nose a day later than in the throat, on about day 3; Peaks after 5-6 days – also a day later than the throat.
Interestingly, the virus injected into the nose first reaches its peak in the throat, lags by one day to the nose, and detects the peak is also a lag of one day.
This has to do with the characteristics of viruses. Because the virus is always looking for a suitable environment for its survival, it is easier to reproduce. Our throat is rich in blood system and has a better metabolism, which may be the easiest part for the virus to survive.
But everything has two sides, the throat is infected more, the virus multiplies quickly, but the human body is also equipped with stronger defenses in this part.
The throat is located at the back of the nasal cavity and is a vital passage into the trachea and lungs. The throat has a very powerful guard - the two tonsils on both sides, and there are many lymphocytes in it to guard our portal and block the invasion of foreign germs, bacteria and viruses. The mucosal immune system of the throat is also relatively strong, and there are a large number of lymphocytes densely packed between the villi epithelial cells covering the surface of the upper throat. Therefore, people often think of the upper throat as an immune organ: once some bacteria and viruses are found, the throat is the first guard to fight them.
Even in healthy people, the lymphocytes in the throat are always in a state of readiness. So the initial symptoms of a cold are sore throat, phlegm and so on. This is exactly how the immunity of the throat area is functioning normally. If human immunity is strong enough here, it can quickly solve the viruses and bacteria in the upper respiratory tract. Therefore, some people do not feel several times a year, even if they catch a cold, they pass quickly within 1-2 days, indicating that his immunity is in a very good state; If a person has a cold for a week or two, and often catches colds throughout the year, then this is a signal from our body to us - to pay more attention to immunity.
So why are 17 of the 36 equally healthy young people never infected by the virus?
The human immune system is like a well-sophisticated, fully divided navy, land and air force, each performing its own duties, cooperating in combat, divided into natural immune system and acquired immune system:
First, the natural immune system
1. Membrane epithelial cells
The human body has a very strong mucosal cell that is very closely connected.
When the virus invades a cell, there is a large class of receptors on it, which, like the FBI's face recognition system, scans for invading substances at any time. Once the RNA of the virus is scanned, it immediately initiates toll-like receptor, and then downstream of it initiates a very important mechanism - the secretion of interferons.
Interferon is a very important substance for antiviral purposes. Our body rapidly synthesizes and secretes a large amount of interferon into the cell. Because interferon not only has to enter a state of readiness, but also notifies nearby cells. These cells have interferon receptors on them, and as soon as they receive the signal, they enter an antiviral state, from all aspects of the viral life cycle - inhibiting transcription, breaking down mRNA, inhibiting translation, packaging, to stop. All in all, the virus cannot survive inside the cell. This process is associated with more than 1,000 proteins and dozens of intracellular channels that bring cells into an antiviral state.
Second, natural immune cells
In addition to the important interferon, the innate immune system can also activate natural killer cells:
Natural killer cells: Natural killer cells are not particularly well understood. But we have at least found that natural killer cells can destroy and disintegrate virus-infected cells after they are activated.
Macrophages (dendritic cells): We collectively refer to them as antigen-presenting cells. It specifically recognizes cells infected by the virus, and then in this way releases some granzyme, perforin, which is like a cannonball-like thing that disintegrates the outer membrane of the virus. Antigen-presenting cells can also activate the adaptive immune system, sending particles of the virus to the surface of the cell, the T cell.
Third, the acquired immune system
1. T cells
Killer T cells: Killer T cells function much like natural killer cells, but they have specific recognition initiation mechanisms. This antigen-presenting cell, by somehow presenting the virus particles to it, activates it, and it can specifically recognize the cells that have been infected by the virus. It also releases granzymes (perforin), something like a cannonball, that disintegrates the outer membrane of the virus. Naturally, this virus has no room to survive.
b. Helper T cells: Helper T cells will differentiate after entering the start-up state from the quiescent state.
· The first type of cell is called TH1, and when TH1 cells are activated, they can play an antiviral role. It mainly secretes some interferon gamma. The secretion of these interferons can make up for some deficiencies of innate immunity and better resist the infection of the virus. This is an important rear addition.
· There are also TH2 cells. What are these cells for? It is mainly the B cells used to activate our body.
2. B cells
B cells are mainly used to produce antibodies — Y-shaped antibodies. These antibodies surround the virus particles in the blood. Viral particles wrapped in antibodies will be more easily recognized by phagocytes and then cleared from the blood and tissues. B cells are also the last to help the body clear the virus.
So these two cells play an important role in helping to clear the virus.
Human antiviral basically has two ideas: natural immunity and specific immunity. In the epidemic, most people's attention is on the acquired immune system: for example, studying vaccines, studying monoclonal antibodies, etc. In fact, the body's natural immune system is also very important in removing viruses. For example, as soon as interferon is started, a large number of secretion copies can adjust the human body to a state that is not easily infected by the virus.
Physical level
From the physical level, the first thing to pay attention to is diet. Eat a healthy diet and pay attention to vitamin C, D, as well as zinc, iron, selenium and other trace elements.
In addition, you should also pay attention to drinking less alcohol and eating less salt. Get a good night's sleep and get plenty of sun.
Psychological level
We live in a society where there will be stress in all aspects of the working family. When the pressure accumulates, the human body will release stress hormones, which directly leads to the human immune cells in a state of inhibited function. This will cause our body's immune cells to not function normally and fight the virus normally.
So we need to decompress ourselves and be exposed to more positive things, whether it's books, films, other art forms, or even some more upscale performances.
In addition, depression, negativity, and anxiety emotions are harmful to our body, and long-term accumulation will inhibit our immune system, so we must take the initiative to eliminate our negative emotions after discovery.
Spiritual level
Psychiatric neuroimmunology scientists have done a lot of research surfaces: people who value the meaning of life have a stronger ability to resist viruses in natural killer cells in the body.
In addition, people with different views of happiness — such as self-actualized, more altruistic people — naturally have an antiviral state in which the secretion of interferons is high and the secretion of inflammatory factors is low.
In addition, there are kindness, honesty and other personalities, which can also comprehensively affect our body's ability to resist viruses.
The deep mystery of boosting immunity
When it comes to boosting immunity, when we talk about the physical aspects - such as vitamin supplementation, everyone can understand it. Vitamins can be observed under the microscope, and the presence of these molecules is real.
When it comes to emotions, relaxation of stress, you may feel that it feels far away, because emotions cannot be observed under the microscope.
When it comes to people's consciousness, spirit, and different concepts of people, at this time, everyone feels more distant, as if it seems a little abstract.
However, people's different spiritual concepts can indeed affect the functional state of human immune cells. Although the spirit cannot be seen under a microscope, it does exist and has an effect on our physical body. People with different views of happiness – hedonistic and altruistic people have different gene expression in their immune cells.
The microscope is just a tool for people. Today with a microscope we can see molecules, maybe in a while, there will be a better microscope, can see atoms or more microscopic things.
The real study of life, health, and human science may not only stop at the material level of molecular cells. In the future, we will continue to expand and expand to the micro - including the spirit, and study its better characteristics.
In the human challenge test, the deeper reason why people are not infected with the new crown may be related to these more microscopic substances.