Specific immunoglobulin: Virus "nemesis" from the plasma of rehabilitation patients-
Interpretation of the technical route of new coronary pneumonia biological drug development
Photo courtesy of Visual China
In the early stage of the new coronary pneumonia outbreak, the lack of specific drugs became an important reason for many people to "talk about crown discoloration."
At a press conference held recently by the Joint Defense and Joint Control Mechanism of the State Council, the progress of scientific research on new coronary pneumonia drug research and vaccine development has attracted attention from all walks of life. Among them, plasma therapy and specific human immunoglobulin have once again been "focused."
"In February, we issued a call to" thousands of people to provide plasma to save thousands of people ". Up to now, more than 2000 plasmas have been collected in the recovery period in the country, and more than 700 cases have been clinically used, showing very good results. "Therapeutic effect." Said Sun Yanrong, deputy director of the Biological Center of the Ministry of Science and Technology.
The upgraded version of "serum (plasma) therapy"-immunoglobulin has also been mentioned: currently has been developed intravenous (intravenous) of new coronary pneumonia human immunoglobulin, can be used for clinical treatment of patients and high-risk groups Passive immune protection.
So, what is the relationship between plasma and immunoglobulin in rehabilitation patients? Why did the ancient "serum therapy" become a powerful weapon during the anti-epidemic period? Why do we need to carry out emergency research on immunoglobulin later? A reporter from Science and Technology Daily interviewed Professor Zhang Juan of China Pharmaceutical University for this purpose.
Serum therapy can be antiviral but the treatment is more extensive
In 1901, the world-famous Nobel Prize in Physiology or Medicine was awarded for the first time, and Emile Adolf von Belling from Germany won this award.
Professors of the Nobel Committee of the Caroline Medical School in Sweden gave such a comment on the contribution of Bellin-"The research on serum therapy, especially the contribution to the treatment of diphtheria, has opened up new ways of research in the medical field. As a result, doctors have powerful weapons against disease and death. "
Diphtheria is an acute respiratory infection caused by diphtheria bacilli. In the 1920s, 13,000-15,000 people died of diphtheria every year in the United States alone.
Bellin and colleagues discovered in the experiment that after injecting the serum of a diabetic but recovering mouse into a new diphtheria mouse, the newly infected diphtheria mouse can still maintain a healthy state.
This means that there is a substance against diphtheria toxin in the recovered mice. They were very excited about this and named the substance "antitoxin".
In 1890, Belling proposed a new concept of "anti-toxin immunity" based on experimental results, which is called "passive immunity against toxins" in medicine.
Before antibiotics were available, the therapy was once used in the treatment of anthrax, smallpox, meningitis, and some diseases that make humans helpless. However, with the advent of vaccines and antibiotics, except for special treatments for a few viruses (such as snake venom and rabies), anti-serums have mostly withdrawn from the clinical frontline.
However, with the emergence of deadly viruses that have neither vaccines nor specific drugs, the traditional sera treatment ideas have been reapplied to the clinic.
During the outbreak of New Coronary Pneumonia, some patients received "serum therapy" and achieved good clinical results. Therefore, some netizens shouted that in the absence of vaccines and special treatment drugs, serum therapy is a blind "magic medicine" and called for active promotion.
However, the Shanghai Institute of Pasteur of the Chinese Academy of Sciences "spilled cold water"-aside from many hidden dangers, let's say that he wanted to use the plasma of the rehabilitated patients to treat the disease, and even help the people of the country to resist the virus. Difficult to achieve ".
"Serum therapy actually uses antibodies in the plasma of rehabilitation patients to neutralize the virus, but some have more plasma antibodies and some have fewer antibodies. Each person's antibody is different in type and ability to neutralize the virus. The treatment is aimed at Sex is more extensive. "Zhang Juan told reporters.
The two therapies have the same ability and immunoglobulin to neutralize viruses
After in-depth research, scientists have gradually clarified the human immune mechanism and formed two treatment paths: active immunity and passive immunity.
"Active immunization is a common vaccine, while passive immunization includes natural passive immunization and artificial passive immunization." Zhang Juan said that the mother's antibodies are passed to the fetus through the placenta or milk, which is natural passive immunization; injection of immunoglobulin, serum to obtain immunity Force belongs to artificial passive immunity.
As an upgraded version of "serum therapy", immunoglobulins are in the same category as serum therapy. They are all derived from the plasma of recovered patients, and they also belong to artificial passive immunotherapy. The difference is that immunoglobulin extracts antibodies produced by B cells in the body through bioengineering methods.
It should be noted that the commonly used intravenous human immunoglobulin belongs to "broad spectrum defense". However, the immunoglobulin extracted from the blood of Xinguan rehabilitation patients has a higher ability to neutralize the new crown virus and higher specificity than the serum of Xinguan patients. After such an immunoglobulin is made into an injection, it must also meet the strict requirements of the drug, with high purity and the ability to neutralize the virus.
The other type of immunoglobulin is specific, such as hepatitis B immunoglobulin, tetanus immunoglobulin, rabies immunoglobulin, etc., only for the pathogen of a single disease.
But no matter what kind of immunoglobulin, it is a short-term passive immunity, and the effect will not last long.
Many people may remember that the news of an HIV-positive antibody was exposed to a domestic company's intravenous injection of human immunoglobulin early last year.
In January 2019, the State Food and Drug Administration also issued the "Announcement on Revising the Instructions for Intravenous Infusion of Human Immunoglobulin and Lyophilized Intravenous Injection of Human Immunoglobulin (No. 1 of 2019)". The announcement contains one of the most important safety Reminder is to add a warning to the instruction manual: because the raw material comes from human blood, although the raw material plasma has been screened for related pathogens, and measures to remove and inactivate viruses have been added to the production process, in theory there is still a certain The potential risks of these known and unknown pathogens should be weighed against clinical use.
After many experimental tests, it was finally confirmed that the batch of drugs had no quality problems, but the discussion about the right and wrong of immunoglobulin did not stop. This may be closely related to the source and use of immunoglobulin.
Immunity is a double-edged sword that cannot be used as a panacea against infection
Many people do not know that the immune response is not absolutely safe. Once the immune system is activated, it will not only kill foreign harmful substances such as viruses and bacteria, but also hurt itself.
"During this new coronary pneumonia epidemic, the storm of inflammatory factors in many patients is related to the overreaction of the immune system." Zhang Juan said that when the body is infected with the virus, the body has not had time to produce antibodies. At this time, many inflammatory factors are produced. The body's immune system will be activated and violently attack the body tissue where the inflammatory factors are located, causing clinical failures such as respiratory failure.
Zhang Juan believes that everyone's immune response is different. Immunoglobulin is a large protein and a foreign substance to the body. The immune system is likely to produce a stress response to foreign substances, so Patients with normal immune system functions do not need to use immunoglobulins.
At present, in clinical practice, there is a phenomenon of abuse like antibacterial drugs. Many people regard intravenous immunoglobulin as a panacea for anti-infection and improving immunity, and give intravenous immunoglobulin treatment to some infected patients.
Zhang Juan pointed out that although intravenous immunoglobulin commonly used in clinic can make people passively improve immunity in a short time, it does not have the relevance of treatment. It is unrealistic to hope that intravenous immunoglobulin is used for pathogen treatment. The effect is not ideal.
Experts analyzed that in order to avoid the abuse or inappropriate reaction of immunoglobulins, the Ministry of Science and Technology emphasized the "specificity" in the emergency research.
Sun Yanrong pointed out at a news conference that this product is derived from the plasma of recovered people and contains high-purity, high-efficiency neutralizing antibodies. After successful development, it can be used for clinical treatment of patients and passive immune protection of high-risk groups.