This is the height of the epidemic and everyone is closely monitoring his progress.

As diagnostic and treatment techniques continue to be researched in depth, more and more people infected with the virus are being declared cured and released from the hospital as they become more knowledgeable and experienced with the virus.

This is probably the most important news we want to hear these days regarding the outbreak.

Because more and more infected people are being cured, some people have come up with their own "treatment ideas" - there should already be antibodies in the blood of the cured, so could some of the blood of these cured people be taken out and injected directly into the infected for treatment, or Can some of the blood from the cured be injected directly into the infected for treatment, or injected into the uninfected for prevention?

Part.1

Coincidentally, your thoughts and questions coincide with those of Bill Gates

Image source: Bill Gates TED talk

In a TED talk, for the Ebola epidemic, Bill Gates has mentioned that one idea is to get the blood of cured patients, process it, and then inject the plasma into the body for protection. He also raised his confusion about how this method has never been tried.

Indeed, after a pathogen such as a virus or bacteria infects the body, the body's immune system will produce the appropriate substances to resist these pathogens, which are familiar to us as antibodies.

Antibodies can bind to pathogens so that they cannot infect normal cells in the body (Photo credit: photojournal.com)

These antibodies are present in the body's bloodstream and work together to complete the cleanup of viruses by binding to certain proteins of the virus and working with other functions of the body's immune system.

Currently, many diseases caused by viral infections do not have targeted specific drugs to treat and prevent them, and most of these diseases are self-limiting, meaning that the body clears the virus through an immune response such as an antibody response.

But therefore, many people have the same question as Bill Gates: "Why can't we inject the treated plasma directly into the body?"

Part.2

Don't be confused between serum and plasma

Since plasma is mentioned, let's briefly explain the difference between it and serum and blood.

Blood contains many components (image source: Pixabay)

Blood, or whole blood, is the red, sticky fluid that flows between the heart and the blood vessels. When blood flows out of our bodies, it naturally clots, and the clotting process precipitates a clear, yellowish liquid, which is the serum.

When the blood is drawn, anticoagulated, and centrifuged to remove the blood cells, the red, opaque, sticky liquid is the plasma that Bill Gates mentioned.

It is true that plasma contains antibodies, but it also contains hormones, plasma proteins, lipoproteins and enzymes, among other products, making it a complex composition. Currently, the knowledge and function of blood components are not fully studied, so it may be risky to inject processed plasma directly into other people.

The serum also contains antibody components. In preclinical experiments, the transfer of antibody-containing mouse serum to healthy, uninfected mice prevented the healthy mice from being infected with the corresponding virus.

Part.3

Serum therapy has existed for a long time, and its feasibility depends on the actual situation

But, unlike what Mr. Bill Gates says, serotherapy has been used by scientists to fight infectious diseases caused by bacteria for more than 100 years.

In 1890, Emil Von Behring (1854-1917) of Germany and Kitasato Shibasaburo (1853-1931) of Japan together announced an important discovery: they kept injecting animals with small amounts of non-lethal tetanus bacteria, which produced in the animals' blood an antitoxin that would neutralize the bacillus toxicity of the tetanus injected into the body. They also noted that serum could be isolated from animals that had acquired immunity to tetanus and injected into other animals to boost their immunity to tetanus.

This is what we call "passive protection", or "serotherapy".

This is theoretically possible for the current epidemic. But as the global population continues to grow, the increased population density makes the spread of infectious diseases more favorable. As of Feb. 11, there were 44,653 confirmed cases of novel coronavirus infection officially notified nationwide, but only 4,740 patients have been cured.

This may explain that question on everyone's mind, "Why can't the treated plasma be injected directly into the body?"

Although serum therapy can be used more effectively to fight or prevent diseases caused by viruses or bacteria, the serum is complex and there is uncertainty as to whether it will cause other problems. Moreover, its existence is relatively short and the amount of serum needed is relatively large. If we were to really help 44,653 people with 4740 people to cure diseases, or even to help the whole country to fight against viruses, I am afraid that draining their blood would be difficult to achieve.

Part.4

Cured patients, you are very important

Although we cannot directly draw the patient's blood to supply the infected, through modern methods, we can analyze and get the whole human monoclonal antibody sequence that can effectively neutralize the virus through the blood of the cured, which can be used to treat and prevent the occurrence of diseases caused by the virus.

After the patient has recovered, antigen-specific B cells are produced in their body. These cells are present in small amounts in the peripheral blood. Through continuous screening, these B cells are captured, and through sequence amplification and analysis, a potent sequence of fully human monoclonal antibodies can be obtained, which can then be prepared in vitro.

This fully human monoclonal antibody is a good therapeutic and preventive tool compared to murine monoclonal antibodies, human-mouse chimeric monoclonal antibodies, and humanized monoclonal antibodies.

This antibody has high affinity, high specificity, and low toxic side effects, which can overcome various disadvantages of animal-derived antibodies and chimeric antibodies.

However, although this method is easy to explain, there are various technical difficulties in practice.

First, antigen-specific B cells are very scarce in peripheral blood. In one study, investigators isolated only 19/500,000 antigen-specific B cells in peripheral blood.

Once isolated, the sensitivity and specificity required for sequence amplification and assay are also very high. Even if the sequence is amplified and the antibody is expressed, the neutralization effect of the antibody needs further identification.

Therefore, the workload and degree of difficulty in actual operation of a seemingly simple and effective method are enormous.

However, with the continuous research and technological development, this method will be more and more frequently and quickly applied in the prevention and treatment of human diseases. Currently, the development of corresponding vaccines and drugs for this coronavirus is also accelerating and intensifying.

Finally, I hope that we can protect ourselves, stay calm and trust science, so that we can overcome the difficulties together.