Nanoantibodies: work continues
From where? From a camel!
The Desert ship helped immunologistsAndrey Subbotin, "Search" No. 39-2014
"Obtaining single–domain nanoantibodies with specified properties and their use for research and applied development" - this was the title of another scientific message delivered at a meeting of the Presidium of the Russian Academy of Sciences. He was addressed by the head of the Laboratory of Molecular Biotechnologies of the Institute of Gene Biology of the Russian Academy of Sciences, Doctor of Biological Sciences Sergey Tillib.
Inquisitive Englishmen T. Lewis and D. Kapniham were the first to attempt to explain the immunity of some animals and people to certain infectious diseases back in the 1870s. At the same time, the French doctor M. Reynaud proved that the introduction of the blood of calves vaccinated against smallpox to cows stops the course of the disease in animals. This was the beginning of immunology. Then there were the discoveries of Koch and Pasteur, other researchers.
In 1890-1892 , E. Bering and Sh .Kitazato discovered the possibility of obtaining diphtheria and tetanus antitoxins, which laid the foundations of immunotherapy. In 1890, they discovered the first antibody (tetanus antitoxin) in the blood serum of an animal. But it was only in 1937 that the research of Tiselius and Kabat initiated the study of the molecular nature of antibodies.
Antibodies (immunoglobulins, IGS) are relatively large (~150 kDa) soluble glycoproteins of blood and tissue fluid that play a central role in the system of humoral immunity. They protect us and our smaller brothers from disease-causing attacks. This process is based on the specific interaction of antibodies with antigens.
Antigens are foreign proteins or other high–molecular compounds. In order to neutralize them, B-lymphocytes synthesize antibodies. Due to the high specificity (selectivity) and the degree of binding to a certain antigen, antibodies and their derivatives are among the most important reagents for use in fundamental applied and medical research...
And our story began with... camels. In 1993, a group of Belgian scientists found out that representatives of this family (camels, alpacas) in the body have unique antibodies with a simplified structure that can "recognize" certain antigens. These antibodies were unusual: they did not consist of four chains of immunoglobulin (two heavy and two light), but had one shortened heavy chain. It became obvious that working with such antibodies is much simpler than most existing technologies in this field. These antibodies, capable of specifically recognizing certain antigens, turned out to be the smallest of all known proteins with similar properties.
The Belgians gave rise to the new term nanobodies, in Russian - "nanoteles" or "nanoantibodies", and if scientifically – single-domain antigen–recognizing variable fragments of special antibodies present (along with traditional antibodies) normally in representatives of the camel family and in some species of cartilaginous fish (sharks and chimeras).
Sergey Tillib was working in Germany at that time and was very interested in the discovery of colleagues. Under his leadership, Russian scientists have mastered and improved a new technology: a camel is immunized (in this case, it was a double-humped camel, as the representative of the Camelidae family most adapted to the conditions of the cold winter of the Moscow region) in order to cause the formation of exactly those antibodies that recognize certain antigens.
Then, after the isolation of RNA from the lymphocytes of an immunized animal, genetic engineering works are carried out in the laboratory and new types of small protein molecules are constructed that neutralize (bind) a given antigen. Camels are "reusable": after immunization, the animal can be reused after 9 months.
In the field of immunobiotechnology, along with classical antibodies and their derivatives, so-called recombinant antigen-binding molecules ("recombinant antibodies") are increasingly used, having the properties of antibodies, but having a somewhat simplified immunoglobulin structure or even a structure completely different from immunoglobulin.
The research of a group of Russian scientists was supported by grants. So, in 2008, the results of the project "Creation of nanoantibodies for effective control of pathological neoangiogenesis induced by vascular endothelial growth factor" were not neglected by Rosnauka (Federal Target Program "Research and Development in priority areas of development of the scientific and technological complex of Russia for 2007-2012"), similar steps towards new promising developments were made by the Russian Academy of Sciences.
Over the years of research, Russian and foreign scientists have confirmed the opinion that many nanoantibodies can withstand significant fluctuations in temperature and acidity of the environment. It has been shown that some nanoantibodies are able to withstand the passage of the human gastrointestinal tract, which makes it possible to take them in the form of ordinary tablets.
Important results of the work of the team of the biomolecular Technologies laboratory under the leadership of S. Tillib were the creation of immune libraries of all variable domains (fragments of special antibodies) of immunized camels, as well as the selection from these libraries of a variety of nanoantibodies specifically recognizing various target antigens (tumor-specific membrane proteins, anti-inflammatory cytokines, surface antigens of a number of viruses and other pathogenic microorganisms).
Sergey Deev, a colleague of S. Tillib, a corresponding member of the Russian Academy of Sciences, stressed that in recent years "immunology has become biotechnology." Today, there are already about 40 drugs created using biotechnological antibodies that are used in the fight against the most serious diseases. The volume of this market in the world is more than $ 50 billion, it is expected that the share of biotechnological drugs in it will soon reach a third. "Now we have the opportunity to create the widest range of diagnostic and therapeutic drugs, biofunctional molecules with a minimum of side effects for human organs and tissues," Sergey Mikhailovich said.
Speaking about the advantages and prospects of using nanoantibodies, Sergey Tillib noted that compared to traditional antibodies, nanoantibodies have a number of potential advantages. They have a smaller size (12-15 kDa, approximately 2x4 nanometers), they are able to recognize and bind fundamentally new antigen sites that are not recognizable and not accessible to conventional antibodies, have good solubility and unusually high resistance. In addition, they can be efficiently generated, selected, modified (including humanized) and economically developed (in bacteria or yeast).
A diagram from the article by Chakravarty et al. Nanobody: The “Magic Bullet” for Molecular Imaging? (Theranostics, 2014) – VM.
Nanoantibodies can be widely used in the medical diagnosis and treatment of oncological and infectious diseases in humans. Together with Belgian and German colleagues, Russian scientists have developed a new approach for monitoring the antigen in living cells. Fluorescent nanoantibodies formed in vivo from genetically engineered structures introduced into cells (from transgenes) are used in a new method of antigen visualization and analysis in living cells, which made it possible to trace the dynamic changes of antigens throughout the cell cycle. In the future, such an approach will be used to track the target antigen during successive stages of development of the organism (so far on the model of fruit fly embryos).
Nanoantibodies are used as functional modules in new-generation biosensors, to produce new medicines, to create new materials based on specific single-domain antibodies for the purification of demanded proteins (for example, in food and animal feed), cell fractionation, hemosorption and removal of certain antigens from biological fluids.
Joint work with the Cancer gene therapy department of the IBG RAS led to the preparation of a drug that blocks the growth of a cancerous tumor. And together with the Laboratory of Immunology of the IBH RAS (head – S.Deev), antibodies with selective anticancer effects on the receptors of epidermal growth factors were obtained.
The discussion of the report was summed up by Academician Ivan Dedov, who called the results obtained in the laboratory of Molecular Biotechnologies of the Institute of Gene Biology of the Russian Academy of Sciences together with colleagues from abroad and from other institutes of the Academy of Sciences, "a huge, large-scale and worthy work."
Portal "Eternal youth" http://vechnayamolodost.ru29.09.2014