The version will allow scientists to test vaccination and treatment methods in the laboratory without fearing exposure to the deadly virus
Because the virus is so contagious and deadly, and a vaccine for it or even a treatment for the disease has not yet been invented, the scientists studying the virus are forced to work in well-isolated laboratories, under strict conditions of protection from the virus. Only a few laboratories in the world can provide such conditions, and as a result the ability of scientists to develop a weapon against the virus is impaired.
At the same time, recently a group of researchers from the University of Wisconsin-Madison managed to find a way to paralyze the virus and limit it to only one type of unique cells. In this way they made the virus safe enough that it could be studied under less stringent conditions than those that exist today.
"We wanted to create an Ebola virus that would be limited by biological means," explains Yoshiro Kawaoka, a professor of pathobiological sciences at the University of Wisconsin-Madison School of Veterinary Medicine. The study, led by Professor Kawaoka, describes the creation of the system that contains and limits the virus and was published on January 21 in the Proceedings of the National Academy of Sciences.
The Ebola virus first emerged in 1976, in outbreaks in Sudan and Zaire. There are several different strains of the virus, which cause severe hemorrhagic fever and death in human victims.
Today, Ebola virus research is limited to the highest level of biological safety, known as Biosafety Level 4. Laboratories that can meet the strict conditions of such a high safety level are rare, and they are usually small and very expensive to maintain. As a result, the basic research needed to develop drugs or vaccines against the virus has been limited to a tiny number of laboratories around the world. The system developed by Kawaoka and his colleagues will make it possible to expand research on the pathogen and speed up the development of weapons against it.
Ebola virus paralysis, according to the study, relies on just one gene known as VP30. Like most viruses, Ebola relies on a tiny number of genes. He only has eight genes, but with the help of these eight genes he takes over human cells and causes them to produce more viruses. The VP30 gene of the virus makes a protein that allows the virus to replicate inside the host cells. Without that protein, the virus cannot reproduce. According to Kawaoka, "the new virus is unable to grow in normal cells."
But the question arises as to how, then, it is possible to test modern means of warfare against the virus. If the upgraded virus can't infect cells anyway, what will the researchers' test be?
To solve the problem, the researchers created genetically engineered cells in which the VP30 protein is continuously produced. When the upgraded virus infects those cells, it is able to multiply because within them is a large pool of the VP30 proteins, which are so necessary for the virus. But if the virus is released and infects the scientist treating it, it will not be able to harm that scientist's cells. Normal human and animal cells do not produce the VP30 protein, so the new virus will not be able to harm them. The key - VP30 - necessary to take over the cell, will be missing.
According to Kawaoka, it took years to find which viral protein is not toxic to cells, so they can be made to produce it themselves. The system created is based on kidney cells from monkey origin in order to trap and multiply the virus.
Kawaoka, as a world-renowned researcher and virologist, is convinced of the safety of the new system. "We did all this work at safety level 4, and the cells we use did not produce viruses that can infect normal cells, even after many replication cycles."
The new virus is identical to the normal Ebola virus in every way, except that it is unable to grow in cells that do not produce the VP30 protein. This fact can lead to a lowering of the level of safety required in the study of the virus, thus leading to the opening of a new era in Ebola research. Dozens of laboratories around the world will start a marathon of studies focused on understanding the structure of the virus, the proteins and genes with which it works and how they can be thwarted. According to Kawaoka, it is almost impossible to conduct studies of this scale in safety level 4 laboratories.
The new system received extensive press coverage from the BBC, The Times and even Nature-News. Doctors and disease researchers hope that soon the system will spread to many laboratories, and that the road from there to the Ebola vaccine will be short.
11 תגובות
Dan,
The gene was completely removed from the genome. The chance that the virus will mutate and reproduce like the original virus is less than zero. Many mutations are needed for this to happen, all in the right direction and at once. Such mutations usually occur in viruses in existing genes. If the gene is completely removed, then the mutations have nothing to work on.
Besides, not all viruses mutate easily or quickly.
Ariel,
According to my understanding, the big problem with viruses is not their presence in the bloodstream, but the fact that they kill human cells in the body. If the engineered viruses can't kill human cells, then I don't see a problem with injecting a controlled amount into the bloodstream so that the immune system recognizes the immune characteristics of the invader.
Michael,
Let's see if I remember the immunology course correctly...
Cells that are infected with a virus externalize the foreign proteins on transmembrane proteins called MHC. The killer white blood cells recognize the foreign factors on the MHC and kill the cells. I don't think there is a process of vaccination for the future.
To the best of my recollection, the vaccination was done through the ingestion of viruses by dendritic white blood cells and macrophages. After the virus is ingested and broken down, they go to the B cells and show them the broken down virus proteins, so that the B cells start producing antibodies against them. This is already a real immune response.
After the infection passes, the antibody-producing B cells undergo refinement, and only those that produce the best antibodies survive. They 'freeze' themselves for periods of decades, until the next time an infection of the same type enters the body. Once this happens, they wake up, multiply rapidly and release a huge amount of specialized and effective antibodies into the bloodstream and tissues. This is the effective immune response that arises following a vaccine.
I am sure at least in the case of the dendritic white blood cells, which are located in the skin area and their job is to capture foreign factors and bring them to the B cells.
Why did the researchers not mention the possibility of vaccination? Do not know. Maybe because it's impossible, maybe because they don't want to be preceded, maybe because it seems obvious to them. Maybe because there is already a very effective vaccine for monkeys... but who is willing to test it on humans?
Greetings friends,
Roy.
If the difference is a change in one gene, how will they prevent the very common situation in viruses that the virus will mutate and reproduce like the original virus?
Roy:
A large part of our immune system is based on the elimination of cells damaged by the virus.
This elimination is based on the fact that the modified cell looks different and this usually happens because it "works for the virus".
When HA does not work for the virus the detection task becomes much more difficult.
It may be possible but doubtful.
What I have almost no doubt about is that the developers of the virus thought of the idea and rejected it (I also thought of the idea but since it was not mentioned in the article I tried to think why and the above is the conclusion I reached. I assume that if among the commenters here at least two thought of the idea then also The virus developers found whoever thought of it)
Roy
Injection of millions of genetically engineered viruses into the body is like an infection and it is hard to believe that the human immune system will be able to deal with a huge amount of viruses which, as you wrote above, are natural for everything and are no different from the normal virus and when you inject a huge amount of viruses you actually eliminate the difference between the genetically engineered virus and the normal virus and creates essentially the same effect
Ariel,
Vaccines have already been invented that have proven their effectiveness (99%) on monkeys. I see no reason why you would prevent the creation of millions of genetically engineered viruses and injecting them into the body as an effective vaccine.
The main problem with the vaccine is that it must be given before the infection, or in the first days of the infection, or it will already cause too much damage to the body.
Apparently what makes this virus so deadly is its ability to reproduce in an enormous amount and it is not possible with the help of one genetically engineered virus or a small amount of genetically engineered viruses to make the body immune to infection with the normal virus which as mentioned reproduces in an enormous amount
Michael,
The engineered virus is identical to the natural virus in every way, except for the lack of that particular gene. It is likely that the body can develop a vaccine against it, if it is injected in appropriate amounts.
But, as usual, 'reasonable' does not necessarily mean that things will work as we expect.
It is not clear to me if this virus can even be used for vaccination because the virus will not infect humans at all.
Avi,
This is an excellent question. I did not find a reference to the subject, although I also had doubts. I guess there is a limited number of studies on such a virus in such a small number of laboratories.
Another problem with the virus is that it erupts unexpectedly and all at once, and in a very short period of time infects everyone present in the environment. It is not possible to vaccinate all the inhabitants of the world against the virus, or even all the inhabitants of the African region. The result is that a vaccine against the virus can probably only help when there is almost certain fear of Ebola being used in biological warfare.
thank you for your response,
Roy.
Why can't the engineered virus be used as a vaccine?