We are used to the fact that the doctor’s words are a virus, they mean more or less that we are sick and need a few days of treatment at home. However, more and more viruses help to heal. And this means that when we hear the words, we should now announce the viruses, so we should be happy.
The word virus comes from Latin and means poison, venom. It is an infectious, potentially pathogenic nucleoprotein that exists only as a single nucleic acid that reproduces genetic material. It is incapable of dividing outside the cell and usually lacks enzymes, and therefore has no metabolism, says the definition of André Lwoff, a French microbiologist who discovered the structure of viruses. These complex organic molecules contain genetic material in the form of RNA (RNA viruses) or DNA, and display both cellular characteristics of living organisms and inanimate matter. Scientists decided to use these properties.
Antibiotics versus phages
Diseases caused by antibiotic-resistant bacteria are an increasingly common problem for doctors. The solution may be bacteriophages – viruses that kill pathogenic microbes. Phages are used to treat i.a. bacterial diseases of the skin, bones, bone marrow and joints. They help in urinary and reproductive tract infections as well as digestive system ailments. They are also used to treat chronic ENT diseases. They are effective in purulent infections of wounds and complications after burns or operations. The advantage of these viruses is the fact that they attack only selected pathogenic microorganisms, so unlike antibiotics, they do not destroy the intestinal bacterial flora. They are also not dangerous to the cells of our body. In Poland, bacteriophages are dealt with by scientists from the Wrocław Center for Phage Therapy at the Institute of Immunology and Experimental Therapy of the Polish Academy of Sciences. The center has its own unique virus collection. People who were not helped by standard therapy and various antibiotics failed to cope with bacterial infections come there.
Cure blindness
Recently, the results of research by scientists from the Oxford Eye Hospital have been presented, which show that specially modified viruses, which are injected with a thin needle into the bottom of the eyeball, significantly improve eyesight. The treatment is intended for people suffering from an inherited form of blindness called choroideremia. It affects one person in 50, mostly men. As a result of a gene error, people suffering from choroideremia begin to lose their eyesight as early as childhood. Ultimately, this leads to full blindness, but most often it doesn’t happen until decades later. The genetically modified virus was injected into volunteers near the dying retina. It infects cells in this part of the eye and begins to produce a copy of the damaged gene in them. This led to the resumption of protein production, the lack of which was the cause of blindness. During the studies, the volunteers were treated with only one eye so that the difference in the quality of vision could be reliably measured. It turned out that the effects were quick and surprisingly good. Scientists do not know yet whether they will be permanent, but one thing is already known – it has been going on for two years, that is, since starting therapy.
Beneficial HIV
In turn, Italian scientists from the Istituto San Raffaele Telethon per la Terapia Genica (TIGET) in Milan decided to apply a therapy using modified HIV viruses. The method they developed is based on equipping the HIV virus with the correct version of the appropriate gene. Later, marrow cells are collected from the patient’s body and combined with the virus in the laboratory. HIV does what viruses do best – it breaks into cells and pastes its genetic material. Only in this case it does not cause disease, but replaces the defective original fragment with the one designed by scientists. The modified cells are then injected into the patient’s body where they resume their normal work. The virus administered in this way turned out to be beneficial for children suffering from rare genetic diseases: metachromatic leukodystrophy (MLD) and Wiskott-Aldrich syndrome. In both cases, medicine did not have any method of treatment so far, which meant that children with these diseases faced disability and then death (after approx. 10 years of life).
This therapy may also prove beneficial for patients whose disease results from defective genes. The virus enters the genome and “exchanges” them for properly functioning ones. Treatment of this type, once considered the most promising branch of modern medicine, has so far been rather disappointing. Thanks to gene therapy, a few diseases have been overcome, and it also carries a serious risk of negative side effects. However, new research shows that this approach is promising.
A method for cancer?
Modified HIV virus also proved to be helpful in the treatment of leukemia, melanoma and kidney cancer. The method was developed by the researcher Wiktor Grochowski. He also used the properties of HIV to reprogram the immune system so that immune cells directly destroy cancer cells.
The method is used in two main variants. In one, T-lymphocytes are modified, i.e. immune cells produced in the bone marrow that mature in the thymus. A gene is inserted into them that stimulates them to fight type B lymphocytes, which undergo malignant transformation in leukemia patients. Inactivated HIV viruses were used to smuggle the new gene. Modified lymphocytes are reintroduced into the patient’s body – doctors inject them, just like cancer patients are given chemotherapeutic drugs. This time, however, instead of drugs, altered immune cells are introduced, which are a kind of “living medicine”. They search for circulating B lymphocytes containing the CD-19 protein and destroy them. The observations to date show that in 45 out of 75 sick children and adults the disease was remitted.
The second method of reprogramming the immune system is by using a therapeutic vaccine. It stimulates the immune system by unblocking certain lymphocytes that start destroying cancer cells. Thanks to such preparations, it was possible to extend the life of patients with advanced melanoma and kidney cancer.
Vegetable capsule
As you can see, a genetically modified virus can serve as a kind of capsule that efficiently and selectively delivers drugs to specific types of cells in the human body. However, scientists developed another new method – they used a plant virus to transfer the load. The authors of this technique are researchers from North Carolina State University. For their research, they used a common plant pathogen, the red clover necrotic mosaic virus. Its particles (virions) were filled with doxorubicin – one of the preparations used in the treatment of cancer (including acute leukemias, multiple myeloma, lymphomas, breast, ovarian, bladder and thyroid cancer). The virus was easy to use because of its unique response to calcium ions. When they are missing from the environment, the proteins that make up the viral shell change their shape – pores open in them, through which the cargo can enter the empty space inside the viral particle. When calcium is added back to the solution, the pores close and the drug becomes trapped inside the capsule. When doxorubicin-filled virions were added to a vessel filled with HeLa cells (HeLa is a type of Helacyton gartlen cancer cells), they rapidly attached to the surface of the cancer cells and began to penetrate inside them. And because the fluid inside the cells, called the cytoplasm, contains tiny amounts of calcium, the virions began to open up again. This resulted in the release of a lethal dose of the chemotherapeutic agent, effectively eliminating HeLa. In addition, the drug-loaded virus did not damage healthy cells. In subsequent studies it turned out that – at least theoretically – with the same efficiency, drugs could be delivered to different types of cells, while maintaining the selective nature of this process. Does this mean that we will soon find cures for all serious diseases? Time will tell.
Ganges – a river that is deadly for bacteriai
The Ganges is a sacred river of Hinduism. The followers of this religion throw the remains of their dead into it. In the 20th century, British scientist Ernest Hankin noticed that although the river was full of decaying bodies, the Ganges water inhibited the growth of the bacteria that causes cholera. However, only after XNUMX years it was proved that bacteriophages – viruses that destroy bacteria – are responsible for this property. Doctors around the world began to research and implement therapies that used these microbes. And bacteriophages are very common in nature, we find them in soil, water and even in the human digestive tract.
However, the discovery of antibiotics has led to phage research being abandoned. Scientists thought that drugs would control any bacterial infections. And so it was until the microbes began to become immunized. Today, there are many bacterial strains that are resistant to penicillin and other popular antibiotics.