How do Corona virus mutations arise?
In the case of COVID-19, antibodies from people who have already recovered can be used for treatment. This is especially helpful for people with weakened immune systems. However, there are concerns among experts that such a treatment will encourage the development of mutations.
Antibody therapy could actually lead to mutations in people with COVID-19 who have a weak immune system, according to a study by experts from University College London. The research was published in the journal published in the English language.Temperate naturePublished.
COVID-19 antibody treatment?
Antibodies from recovered people can be used to treat COVID-19, and it is especially helpful for people with weakened immune systems. However, the researchers explained that such a treatment has the drawbacks that it can boost virus mutations, especially in people with weakened immune systems.
For example, when people are immunocompromised as a result of chemotherapy, the immune system has great difficulty fighting dangerous viruses effectively. In such a situation, the antibodies used in the treatment receive very little support from so-called cytotoxic T cells. This will reduce the possibility of the virus getting rid of quickly in the body.
This often makes infections chronic, which increases the risk of a virus mutation. This could lead to different types of the virus with completely new properties, according to the team’s report. If antibodies from recovered subjects are used in serum therapy, it is the viral variants that these antibodies are less effective against. Experts also speculate that this effect could be similar if the vaccination was not sufficiently effective.
Is there a relationship between chronic infection, mutagenesis and serum therapy?
The research group studied the relationship between chronic infection, mutagenesis and serum therapy in an immunocompromised 70-year-old man with COVID-19 for a period of 101 days. The patient had a tumor in the lymphatic system and was treated with chemotherapy, which weakened the immune system.
Effects of serum therapy
When a man fell ill with the COVID-19 virus, serum therapy was also performed among other treatments. At first, this stabilized the condition, but then gradually deteriorated, culminating in the patient’s eventual death. Over the course of 101 days, the researchers took a total of 23 virus samples, whose genomes were sequenced. This allowed the team to closely monitor how the virus mutated.
The virus variant survived the antibody treatment
The researchers noted that after two treatments with the antibody serum treatment, the most significant change in virus count occurred between day 66 and 82. The type of virus that survived the antibody treatment became predominant. This has a double deletion, resulting in a loss of two amino acids in the protein.
The alteration, known as H69 / V70, occurs near the prickly protein receptor binding site. The researchers explained that the virus uses this as a kind of key to reach cells.
The mutations altered the spike’s protein structure
In addition, another mutation occurred (D796H) and both mutations together led to an alteration of the protein spiky structure. The team added that this means that the taken antibodies are no longer able to adapt to the virus and neutralize it as well.
There is no risk for people with a healthy immune system?
The researchers explain that if people have healthy immune systems, the virus is less likely to mutate through serum therapy, as it is in people who are immunocompromised. Because in healthy people, the antibodies present are better supported by so-called cytotoxic T cells. These cells are able to identify and destroy affected cells. Those skilled in this area add that the antibodies and cytotoxic T cells together have a greater potential to eradicate viruses.
The mutation doubled the infection of the virus
The team also created viruses that contained the H69 / V70 deletion, the D796 mutation, or both at the same time. Using these viruses, researchers were able to analyze the causes of the mutations occurring. And it was found in laboratory experiments that deletion doubled the infection of the virus compared to the old form of the virus. The deletion of H69 / V70 is also included in the UK COVID-19 variant B.1.1.7.
In the D796H, the receptor binding site was altered in such a way that it was no longer easy for antibodies from recovered people with COVID-19 to detect the virus, which contributed to reducing the efficacy of the serum treatment, the researchers explain. The virus appeared to outperform the active ingredients used by the mutations.
According to experts, such types of virus are unlikely to develop in people with healthy immune systems. This is due to better immune control, with which fewer viruses can appear.
The researchers explained that the vaccine treatment encouraged the selection of virus variants that are less sensitive or insensitive to antibodies in the person subject to examination who has a weak immune system. Basically, there is competition between different virus variants, which is fueled by serum treatment.
Use caution when treating immunocompromised people
The results indicate that special care should be taken when treating immunocompromised people, as the virus has more time to reproduce, as SARS-CoV-2 has more chances to mutate in such a condition, the researchers emphasized. Serum therapy for people with weakened immune systems should only be carried out within the framework of studies and ideally in single rooms with increased infection control precautions due to the increased risk of virus mutations. Experts also advise that the virus be sequenced at all times.
Serum therapies are only used on a limited scale
Meanwhile, according to experts, it is also clear that serum treatments are only effective under certain conditions, even in people with a healthy immune system. In the United States, the U.S. Food and Drug Administration (FDA) has restricted the use of serum treatments. In the future, this remedy should be used only in the early stage of treatment (in the first 72 hours). In addition, it can also be used in people whose immune cells do not produce enough antibodies for effective defense, according to the researchers. (Like)
Author and source information
This text complies with the requirements of the specialized medical literature, medical guidelines and current studies and has been examined by medical professionals.
- Steven A. Kemp, Dami A. Collier, Rawlings P. Datir, Isabella ATM Ferreira, Salma Gayed et al: The evolution of SARS-CoV-2 during the treatment of chronic infection, in nature (veröffentlicht 05.02.2021), Temperate nature
- University College London: Important new variants of SARS-CoV-2 may appear during chronic infection (veröffentlicht 05.02.2021), ucl.ac.uk/
This article is for general guidance only and should not be used for self-diagnosis or self-medication. He cannot replace a visit to the doctor.
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