Biological common sense tells us that when a person is infected with a disease and healed, the antibodies to the disease in the body will still remain, and if the same pathogen invades the body again, the antibodies will react quickly to eliminate the virus. Thus, when plasma or serum containing viral antibodies is injected into the body of a critically ill person, it is theoretically possible to think that these antibodies can help the immune system and viruses in critically ill patients.
Based on this principle, the team at Imperial College of Technology has begun working on the vaccine, which is expected to begin human clinical trials as early as June.
Stimulates the immune response to produce antibodies
Professor Paul McKay, a researcher in the vaccine development team at Imperial College of Technology, told First Business that they were most interested in the immune response mechanism that produces blood antibodies, and by simulating it, the vaccine has been developed and animal trials have begun.
Professor McKay told First Financial: “We used the anti-original vaccine on the surface of the virus. This is because when the virus re-enters the body, the virus antigen can be quickly identified by the human body, activating the immune response, so that the body produces antibodies to neutralize the virus, so as to prevent infection, even if the vaccine can not completely kill the virus, at least can reduce the ability of the virus to spread in the body. “
McKay told First Finance that the vaccine has been injected into mice and will be watched in the coming weeks to see how antibodies in mice are immune to the new coronavirus. Professor McKay expects human clinical trials to begin as early as June if animal trials go well.
As for the method of developing a vaccine to simulate the human immune response mechanism, a researcher in the field of viral immunity told First Financial: “This method is not simple, because the serum composition is very complex, first of all, the analysis of the elements that play a protective role in the human body, that is, effective antibodies, in order to be used in vaccine simulation.” “
He explained that the principle of the vaccine is to identify the virus antigen, inactivated antigen into the human body, induce antibodies, until the next time the same antigen re-entered the human body, antibodies can automatically identify the virus antigen, so as to neutralize the virus, reduce the infection of the virus. “Another technical difficulty now is that even knowing which antigens are not necessarily able to isolate antibodies that can identify them, and top scientific teams around the world are working on it. The researcher told first financial reporters.
The Imperial College of Technology team studied SARS coronavirus 17 years ago, giving them an edge in the development of the new coronavirus vaccine.
Plasma antibody therapy has been validated
There is also a view that the use of plasma or serum in recovered patients to treat infected patients is more straightforward than inactivated vaccines that stimulate the body’s immune system to produce corresponding antibodies.
China’s biology, a super-big factory engaged in the research and production of vaccines and blood products, announced late On February 13th that it had detected high-efficiency valence virus neutralizing antibodies in the plasma of those recovering from the new coronavirus pneumonia, and after inactivated treatment, the new coronavirus-free plasma products were prepared, saving 11 critically ill patients.
Clinical first-line research found that the new coronavirus pneumonia patients, 12 to 24 hours after receiving plasma antibody treatment, laboratory testing of the main inflammatory indicators significantly decreased, lymphocyte ratio increased, blood oxygen saturation, viral load and other key indicators overall good, clinical signs and symptoms significantly improved. This proves that the plasma with antibodies in the body of the recovering person can have a therapeutic effect.
In fact, as early as the National Health and Reform Commission issued a trial of the fourth edition of the “new coronary virus infection pneumonia diagnosis and treatment program” has been formally put forward: “the treatment of heavy, critical patients can be used for recovery plasma treatment.” “
Only a few healers have strong antibody specificity
But the treatment is not as simple in practice as the theory sounds. The biggest challenge is the scarcity of antibodies. Not only because the number of people with cured patients is still relative to the number of seriously ill patients, as of February 14, there were 9,278 cases of severe coronavirus pneumonia, with a cumulative total of 3,862 discharges; Only a small number of healers have highly specific viral antibodies in their plasma, and not all antibodies can be used.
Studies have shown that antigen-specific B cells are very rare in peripheral blood, and even after separation to B cells, the sensitivity and specificity of their sequences is very high. Even if the antibody is expressed, the neutralizing effect of the antibody needs to be further identified.
On the other hand, the treatment process is not simply isolated plasma and then lost to patients, but also need to go through strict blood biosecurity testing, virus inactivation, antiviral activity testing, etc., in order to be used in clinical treatment. But even so, as the researchers say, the complex composition of the serum is uncertain about whether there are other risks to the patient, so there is a risk of infection during the transfusion process.
Another scientific and technological tool is to extract a whole-human monoclonal antibody sequence that effectively neutralises the virus by analyzing the healing blood, which can be used to treat and prevent the occurrence of virus-induced diseases. However, this method needs to be validated in clinical trials, from the discovery of antibodies to the ability of antibodies to express large amounts of them in high-yielding cells for a long time, so this method is not the first choice for responding to outbreaks.
Combined with the above methods, in the current situation of no better drug treatment and alternative means, the direct use of the plasma of rehabilitation patients for the treatment of seriously ill patients is a stopgap measure, so that some life-threatening patients with critical illness, see the hope of life.