Production and characterisation of a SARS-CoV-2 S-protein RBD homodimer with increased avidity for specific antibodies

Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies.The aim of the study was to obtain and characterise a SARS-CoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies.Materials and methods: the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved mono clonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones.Results: the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD’s ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30–50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies.Conclusions: the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein

Comparison of different technologies for producing recombinant adeno-associated virus on a laboratory scale

Adeno-associated virus vectors are among the most promising ones for the delivery of transgenes to various organs and tissues. Recombinant adeno-associated virus (rAAV) is able to transduce both dividing and non-dividing cells, has low immunogenicity, and is able to provide long-term expression of transgenes. Modern technologies make it possible to obtain rAAV for in vivo use, but they are not without drawbacks associated with laboriousness, scalability difficulties, and high cost, therefore, improvement of technological schemes for obtaining rAAV is an urgent issue. The aim of the study was to compare different technological approaches to rAAV production based on different conditions of the transfected HEK293 cell line cultivation on a laboratory scale. Materials and methods: HEK293 cell culture, AAV-DJ Packaging System, PlasmidSelect Xtra Starter Kit were used in the study. The technologies were compared using a model rAAV vector with a single-domain antibody transgene fused to the Fc-fragment of IgG1 specific to botulinum toxin. HEK293 cells were transfected with supercoiled plasmid DNA isolated by three-step chromatographic purification. The identity of the rAAV preparation was determined by electrophoresis, immunoblotting, and real-time polymerase chain reaction. Results: the study demonstrated the efficiency of the chromatographic method for obtaining a supercoiled form of plasmid DNA that can be used for efficient transfection of cell culture in order to produce rAAV. The study compared the following processes of rAAV production: using transient transfection and cultivation of the transfected HEK293 cell suspension in Erlenmeyer flasks, adherent culture in T-flasks, and adherent culture in a BioBLU 5p bioreactor on a matrix of Fibra-Cel disks. Conclusions: the data obtained showed the possibility of using the described approaches to purification of plasmid DNA, cell transfection, and cultivation of the transfected cells under various conditions to obtain rAAV samples that expresses the antibody gene. The BioBLU 5p reactor with Fibra-Cel discs was used for the first time to produce preparative quantities of rAAV on a laboratory scale, which increased the adherent surface area during cell culture and transfection, and, as a result, increased the yield of the target product

Protecting Mice from H7 Avian Influenza Virus by Immunisation with a Recombinant Adenovirus Encoding Influenza A Virus Conserved Antigens

Influenza is a highly contagious disease that causes annual epidemics and occasional pandemics. Birds are believed to be the source of newly emerging pandemic strains, including highly pathogenic avian influenza viruses of the subtype H7. The aim of the study: to evaluate the ability of the recombinant human adenovirus, serotype 5, which expresses genes of influenza A highly conserved antigens (ion channel M2 and nucleoprotein NP), to provide protection to laboratory mice against infection with a lethal dose of avian influenza virus, subtype H7. To achieve this goal, it was necessary to adapt influenza A virus, subtype H7 for reproduction in the lungs of mice, to characterise it, and to use it for evaluation of the protective properties of the recombinant adenovirus. Materials and methods: avian influenza virus A/Chicken/NJ/294508-12/2004 (H7N2) was adapted for reproduction in the lungs of mice by repeated passages. The adapted strain was sequenced and assessed using hemagglutination test, EID50 and LD50 for laboratory mice. BALB/c mice were immunised once with Ad5-tet-M2NP adenovirus intranasally, and 21 days after the immunisation they were infected with a lethal dose (5 LD50) of influenza virus A/Chicken/NJ/294508-12/2004 (H7N2) in order to assess the protective properties of the recombinant adenovirus. The level of viral shedding from the lungs of the infected mice was evaluated by titration of the lung homogenates in MDCK cell culture on days 3 and 6 after infection. The level of specific antibodies to H7 avian influenza virus was determined by indirect enzyme immunoassay. Results: the use of Ad5-tet-M2NP adenovirus for immunisation of the mice ensured 100% survival of the animals that had disease symptoms (weight loss) after their infection with the lethal dose (5 LD50) of H7 avian influenza virus. The study demonstrated a high post-vaccination level of humoral immune response to H7 avian influenza virus. The virus titer decreased significantly by day 6 in the lungs of mice that had been immunised with Ad5-tet-M2NP compared to the control group. Conclusion: the Ad5-tetM2NP recombinant adenovirus can be used to create a candidate pandemic influenza vaccine that would protect against avian influenza viruses, subtype H7, in particular

Получение и характеристика гомодимерной формы RBD S-белка SARS-CoV-2, обладающей повышенной авидностью к специфическим антителам

Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies. The aim of the study w as t o obtain and characterise a SARSCoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies. Materials and methods: the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved monoclonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones. Results: the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD’s ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30–50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies. Conclusions: the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein.Важным параметром, оцениваемым при мониторинге иммунной прослойки у населения и эффективности вакцинации населения, является уровень вируснейтрализующих антител. Разработка подхода к выявлению вируснейтрализующих антител к вирусу SARS-CoV-2 с помощью безопасного, простого и быстрого метода, не требующего использования живых вирусов, имеет большое значение для борьбы с пандемией COVID-19. Для разработки тест-систем для проведения иммуноферментного анализа (ИФА), детектирующих потенциально вируснейтрализующие антитела, необходимо получение высокоочищенного рекомбинантного рецептор-связывающего домена (RBD) S-белка, обладающего высокой авидностью к специфическим антителам. Цель работы: получение и характеристика гомодимерной формы RBD S-белка вируса SARS-CoV-2, а также клеточной линии, продуцирующей рекомбинантный RBD, для создания ИФА тест-системы для выявления потенциально вируснейтрализующих антител. Материалы и методы: дизайн генетической конструкции проводили in silico. Стабильную клеточную линию получали при помощи трансфекции клеток CHO-S, селекции на антибиотике и отбора оптимального клона. Рекомбинантный RBD очищали с использованием хроматографических методов, получали мономерную и гомодимерную формы RBD. Активность полученных форм анализировали с использованием методов Вестерн-блот, биослойной интерферометрии и непрямго ИФА. Для анализа использовали моноклональные антитела GamXRH19, GamP2C5 и h6g3, а также образцы сывороток крови добровольцев, вакцинированных препаратом Гам-КОВИД-Вак, и невакцинированных добровольцев. Результаты: получена клеточная линия CHO-S, стабильно продуцирующая рекомбинантный RBD S-белка вируса SARS-CoV-2. Показано, что при культивировании данной клеточной линии в режиме fed-batch более 7 суток рекомбинантный RBD способен образовывать гомодимеры за счет наличия неспаренных цистеинов. Количественный выход очищенного рекомбинантного RBD из культуральной жидкости составил 30–50 мг/л. Мономерная и гомодимерная формы RBD были разделены при помощи гель-фильтрации и охарактеризованы по способности взаимодействовать со специфическими моноклональными антителами, а также сыворотками крови от вакцинированных добровольцев. Продемонстрировано, что именно гомодимерная форма рекомбинантного RBD обладает повышенной авидностью к моноклональным антителам и антителам в сыворотке крови вакцинированных. Выводы: гомодимерная форма рекомбинантного RBD может являться более предпочтительной для анализа уровня антител к рецептор-связывающему домену S-белка вируса SARS-CoV-2

Способ получения рекомбинантных антител, продуцируемых клеточной линией, трансдуцированной рекомбинантными аденовирусами

Objectives. To develop a technology for obtaining recombinant antibodies in a suspension culture of human HEK293 cells using transduction with recombinant adenovirus serotype 5 (rAd5) carrying genes expressing heavy and light chains of antibodies on the example of two broadspectrum anti-influenza antibodies 27F3 and CR9114.Methods. Ad5-27F3-H, Ad5-CR9114-H, and Ad5-27F3-L recombinant adenoviruses carrying the 27F3 antibody heavy chain gene, CR9114 antibody heavy chain gene, and 27F3 light chain gene, respectively, were generated using the AdEasy™ Adenoviral vector system. To accumulate preparative amounts of recombinant r27F3 and rCR9114 antibodies, the HEK293 suspension cell line was transduced with recombinant adenoviruses carrying genes for heavy and light chains of antibodies. The cells were cultured in a wave-type bioreactor. Chromatography was used to purify recombinant antibodies from the culture medium. After analyzing the molecular weights of purified antibodies using protein electrophoresis, their ability to interact with influenza A and B viruses was analyzed using the Western blot technique, while their ability to neutralize influenza A and B viruses was evaluated using the virus neutralization assay.Results. A method for the accumulation and purification of recombinant r27F3 and CR9114 antibodies from the culture medium of a suspension culture of human cells following transduction with its recombinant adenoviruses carrying the genes for heavy and light chains of these antibodies was developed. The ability of the r27F3 antibody to interact with and neutralize influenza A viruses of group 1 (except influenza A virus subtype H2) and group 2 was shown. The ability of the rCR9114 antibody to interact with influenza A viruses of group 1 and influenza B viruses, as well as to neutralize influenza A viruses of group 1, was demonstrated.Conclusions. A technology for obtaining recombinant antibodies in a suspension culture of HEK293 cells using transduction with recombinant adenoviruses carrying genes expressing heavy and light chains of antibodies was developed along with a confirmation of their specificity.Цели. Разработать технологию получения рекомбинантных антител в суспензионной культуре клеток человека HEK293 с помощью трансдукции рекомбинантными аденовирусами человека пятого серотипа, несущими гены, экспрессирующие тяжелые и легкие цепи антител, на примере двух противогриппозных антител широкого спектра действия 27F3 и CR9114.Методы. Рекомбинантные аденовирусы Ad5-27F3-H, Ad5-CR9114-H и Ad5-27F3-L, несущие ген тяжелой цепи антитела 27F3, ген тяжелой цепи антитела CR9114 и ген легкой цепи 27F3, были получены с помощью набора AdEasy™ Adenoviral vector system. Для накопления препаративных количеств рекомбинантных антител r27F3 и rCR9114 суспензионную клеточную линию HEK293 трансдуцировали рекомбинантными аденовирусами, несущими гены тяжелых и легких цепей антител, и культивировали клетки в биореакторе волнового типа. Рекомбинантные антитела очищали из культуральной жидкости хроматографическим методом. Молекулярную массу полученных антител анализировали с помощью белкового электрофореза, их способность взаимодействовать с вирусами гриппа А и В методом вестерн-блот анализа, а способность нейтрализовать вирусы гриппа А и В с помощью реакции вирус-нейтрализации.Результаты. Отработана методика накопления и очистки рекомбинантных антител r27F3 и CR9114 из культуральной жидкости суспензионной культуры клеток человека после трансдукции ее рекомбинантными аденовирусами, несущими гены тяжелых и легких цепей этих антител. Показана способность антитела r27F3 взаимодействовать с вирусами гриппа А подгруппы 1 (кроме вируса грипп А субтипа H2) и подгруппы 2 и нейтрализовать их. Показана способность антитела rCR9114 взаимодействовать с вирусами гриппа А подгруппы 1 и вирусами гриппа В, а также нейтрализовать вирусы гриппа А подгруппы 1.Выводы. Отработана технология получения рекомбинантных антител в суспензионной культуре клеток HEK293 с помощью трансдукции рекомбинантными аденовирусами, несущими гены, экспрессирующие тяжелые и легкие цепи антител, и показана их специфичность

Сравнение различных технологий получения рекомбинантного аденоассоциированного вируса в лабораторном масштабе

Adeno-associated virus vectors are among the most promising ones for the delivery of transgenes to various organs and tissues. Recombinant adeno-associated virus (rAAV) is able to transduce both dividing and non-dividing cells, has low immunogenicity, and is able to provide long-term expression of transgenes. Modern technologies make it possible to obtain rAAV for in vivo use, but they are not without drawbacks associated with laboriousness, scalability difficulties, and high cost, therefore, improvement of technological schemes for obtaining rAAV is an urgent issue. The aim of the study was to compare different technological approaches to rAAV production based on different conditions of the transfected HEK293 cell line cultivation on a laboratory scale. Materials and methods: HEK293 cell culture, AAV-DJ Packaging System, PlasmidSelect Xtra Starter Kit were used in the study. The technologies were compared using a model rAAV vector with a single-domain antibody transgene fused to the Fc-fragment of IgG1 specific to botulinum toxin. HEK293 cells were transfected with supercoiled plasmid DNA isolated by three-step chromatographic purification. The identity of the rAAV preparation was determined by electrophoresis, immunoblotting, and real-time polymerase chain reaction. Results: the study demonstrated the efficiency of the chromatographic method for obtaining a supercoiled form of plasmid DNA that can be used for efficient transfection of cell culture in order to produce rAAV. The study compared the following processes of rAAV production: using transient transfection and cultivation of the transfected HEK293 cell suspension in Erlenmeyer flasks, adherent culture in T-flasks, and adherent culture in a BioBLU 5p bioreactor on a matrix of Fibra-Cel disks. Conclusions: the data obtained showed the possibility of using the described approaches to purification of plasmid DNA, cell transfection, and cultivation of the transfected cells under various conditions to obtain rAAV samples that expresses the antibody gene. The BioBLU 5p reactor with Fibra-Cel discs was used for the first time to produce preparative quantities of rAAV on a laboratory scale, which increased the adherent surface area during cell culture and transfection, and, as a result, increased the yield of the target product.Векторы на основе аденоассоциированного вируса являются одними из наиболее перспективных для доставки трансгенов в различные органы и ткани. Рекомбинантный аденоассоциированный вирус (rAAV) способен трансдуцировать как делящиеся, так и неделящиеся клетки, обладает низкой иммуногенностью и способен обеспечивать долгосрочную экспрессию трансгенов. На сегодняшний день существуют технологии, позволяющие получать rAAV для применения in vivo, однако они не лишены недостатков, связанных с трудоемкостью, сложностями масштабирования и высокой стоимостью, поэтому вопрос об усовершенствовании технологических схем получения rAAV является актуальным. Цель работы: сравнение технологических подходов к получению rAAV, основанных на различных условиях культивирования трансфицированной клеточной линии HEK293 в лабораторном масштабе. Материалы и методы: в исследовании использовали культуру клеток HEK293, плазмидную систему AAV-DJ Packaging System, систему PlasmidSelect Xtra Starter Kit. В качестве модели для сравнения технологий использовали вектор rAAV с трансгеном однодоменного антитела, слитого с Fc-фрагментом IgG1, специфичного к ботулотоксину. Применяли метод трансфекции клеток HEK293 суперскрученной плазмидной ДНК, выделенной при помощи трехступенчатой хроматографической очистки. Определение подлинности препарата rAAV проводили методами электрофореза, иммуноблоттинга и полимеразной цепной реакции в режиме реального времени. Результаты: продемонстрирована эффективность получения суперскрученной формы плазмидной ДНК, применимой для эффективной трансфекции с целью получения rAAV. Проведено сравнение процесса транзиентной трансфекции и культивирования трансфицированных клеток HEK293 в условиях суспензии в колбах, адгезии в культуральных флаконах и адгезии в биореакторе BioBLU 5p на матрице из дисков Fibra-Cel с целью продукции rAAV. Выводы: показана возможность применения описанных подходов к очистке плазмидной ДНК, трансфекции и культивированию трансфицированных клеток в различных условиях для получения препарата rAAV, эспрессирующего ген антитела. Реактор BioBLU 5p с дисками Fibra-Cel был впервые использован для получения препаративных количеств rAAV в лабораторном масштабе, что позволило увеличить площадь поверхности адгезии при культивировании и трансфекции клеток и, как следствие, увеличить выход целевого продукта

rAAV expressing recombinant antibody for emergency prevention and long-term prophylaxis of COVID-19

IntroductionNumerous agents for prophylaxis of SARS-CoV-2-induced diseases are currently registered for the clinical use. Formation of the immunity happens within several weeks following vaccine administration which is their key disadvantage. In contrast, drugs based on monoclonal antibodies, enable rapid passive immunization and therefore can be used for emergency pre- and post-exposure prophylaxis of COVID-19. However rapid elimination of antibody-based drugs from the circulation limits their usage for prolonged pre-exposure prophylaxis.MethodsIn current work we developed a recombinant adeno-associated viral vector (rAAV), expressing a SARS-CoV-2 spike receptor-binding domain (RBD)-specific antibody P2C5 fused with a human IgG1 Fc fragment (P2C5-Fc) using methods of molecular biotechnology and bioprocessing.Results and discussionsA P2C5-Fc antibody expressed by a proposed rAAV (rAAV-P2C5-Fc) was shown to circulate within more than 300 days in blood of transduced mice and protect animals from lethal SARS-CoV-2 virus (B.1.1.1 and Omicron BA.5 variants) lethal dose of 105 TCID50. In addition, rAAV-P2C5-Fc demonstrated 100% protective activity as emergency prevention and long-term prophylaxis, respectively. It was also demonstrated that high titers of neutralizing antibodies to the SARS-CoV-2 virus were detected in the blood serum of animals that received rAAV-P2C5-Fc for more than 10 months from the moment of administration.Our data therefore indicate applicability of an rAAV for passive immunization and induction of a rapid long-term protection against various SARS-CoV-2 variants

Защита мышей от заражения вирусом гриппа птиц субтипа H7 с помощью иммунизации рекомбинантным аденовирусом, кодирующим консервативные антигены вируса гриппа А

Influenza is a highly contagious disease that causes annual epidemics and occasional pandemics. Birds are believed to be the source of newly emerging pandemic strains, including highly pathogenic avian influenza viruses of the subtype H7. The aim of the study: to evaluate the ability of the recombinant human adenovirus, serotype 5, which expresses genes of influenza A highly conserved antigens (ion channel M2 and nucleoprotein NP), to provide protection to laboratory mice against infection with a lethal dose of avian influenza virus, subtype H7. To achieve this goal, it was necessary to adapt influenza A virus, subtype H7 for reproduction in the lungs of mice, to characterise it, and to use it for evaluation of the protective properties of the recombinant adenovirus. Materials and methods: avian influenza virus A/Chicken/NJ/294508-12/2004 (H7N2) was adapted for reproduction in the lungs of mice by repeated passages. The adapted strain was sequenced and assessed using hemagglutination test, EID50 and LD50 for laboratory mice. BALB/c mice were immunised once with Ad5-tet-M2NP adenovirus intranasally, and 21 days after the immunisation they were infected with a lethal dose (5 LD50) of influenza virus A/Chicken/NJ/294508-12/2004 (H7N2) in order to assess the protective properties of the recombinant adenovirus. The level of viral shedding from the lungs of the infected mice was evaluated by titration of the lung homogenates in MDCK cell culture on days 3 and 6 after infection. The level of specific antibodies to H7 avian influenza virus was determined by indirect enzyme immunoassay. Results: the use of Ad5-tet-M2NP adenovirus for immunisation of the mice ensured 100% survival of the animals that had disease symptoms (weight loss) after their infection with the lethal dose (5 LD50) of H7 avian influenza virus. The study demonstrated a high post-vaccination level of humoral immune response to H7 avian influenza virus. The virus titer decreased significantly by day 6 in the lungs of mice that had been immunised with Ad5-tet-M2NP compared to the control group. Conclusion: the Ad5-tetM2NP recombinant adenovirus can be used to create a candidate pandemic influenza vaccine that would protect against avian influenza viruses, subtype H7, in particular.Грипп – высококонтагиозное заболевание, вызывающее ежегодные эпидемии и через неравные интервалы времени – пандемии. Источником вновь возникающих пандемичных штаммов, как правило, являются птицы, а наибольшее беспокойство в настоящее время вызывают высокопатогенные вирусы гриппа птиц субтипа H7. Цель работы: оценить способность рекомбинантного аденовируса человека пятого серотипа, экспрессирующего гены высококонсервативных антигенов вируса гриппа А (ионного канала М2 и нуклеопротеина NP), обеспечивать защиту от заражения лабораторных мышей летальной дозой вируса гриппа птиц субтипа H7. Для достижения цели необходимо было адаптировать для размножения в легких мышей вирус гриппа А субтипа Н7, охарактеризовать и с его помощью оценить защитные свойства рекомбинантного аденовируса. Материалы и методы: вирус гриппа птиц A/Chicken/NJ/294508-12/2004 (H7N2) был адаптирован для размножения в легких мышей путем многократного пассирования. Этот штамм был секвенирован и охарактеризован в реакции гемагглютинации, установлены его ЭИД50 и ЛД50 для лабораторных мышей. Для изучения защитных свойств рекомбинантного аденовируса мыши линии BALB/c были иммунизированы аденовирусом Ad5-tet-M2NP однократно интраназально и через 21 сутки после иммунизации заражены летальной дозой (5 ЛД50) вируса гриппа птиц A/Chicken/NJ/294508-12/2004 (H7N2). Уровень вирусовыделения из легких мышей был оценен на 3 и 6 сутки после заражения с помощью титрования гомогенатов легких на культуре клеток MDCK. Уровень специфических антител к вирусу гриппа птиц субтипа Н7 определяли методом непрямого иммуноферментного анализа. Результаты: иммунизация мышей аденовирусом Ad5-tet-M2NP при наличии симптомов заболевания (снижение массы тела) обеспечила 100% выживаемость животных после заражения летальной дозой (5 ЛД50) вируса гриппа птиц субтипа H7. Продемонстрирован высокий поствакцинальный уровень гуморального иммунного ответа к вирусу гриппа птиц субтипа H7. Показано, что в легких мышей из группы, иммунизированной Ad5-tet-M2NP, уже к 6 суткам наблюдалось существенное снижение титра вируса гриппа птиц субтипа H7 по сравнению с контрольной группой. Заключение: рекомбинантный аденовирус Ad5-tet-M2NP может быть использован для создания потенциальной пандемичной противогриппозной вакцины, в том числе и от вирусов гриппа птиц субтипа H7

Safety and immunogenicity of rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine against SARS-CoV-2 in healthy adolescents: an open-label, non-randomized, multicenter, phase 1/2, dose-escalation study

To protect young individuals against SARS-CoV-2 infection, we conducted an open-label, prospective, non-randomised dose-escalation Phase 1/2 clinical trial to evaluate the immunogenicity and safety of the prime-boost “Sputnik V” vaccine administered at 1/10 and 1/5 doses to adolescents aged 12–17 years. The study began with the vaccination of the older cohort (15-to-17-year-old participants) with the lower (1/10) dose of vaccine and then expanded to the whole group (12-to-17-year-old participants). Next, 1/5 dose was used according to the same scheme. Both doses were well tolerated by all age groups. No serious or severe adverse events were detected. Most of the solicited adverse reactions were mild. No significant differences in total frequencies of adverse events were registered between low and high doses in age-pooled groups (69.6% versus 66.7%). In contrast, the 1/5 dose induced significantly higher humoral and T cell-mediated immune responses than the 1/10 dose. The 1/5 vaccine dose elicited higher antigen-binding (both S and RBD-specific) as well as virus-neutralising antibody titres at the maximum of response (day 42), also resulting in a statistically significant difference at a distanced timepoint (day 180) compared to the 1/10 vaccine dose. Higher dose resulted in increased cross-neutralization of Delta and Omicron variants.;Clinical Trial RegistrationClinicalTrials.gov, NCT04954092, LP-007632

NANOBODIES: STRUCTURE, MANUFACTURING, APPLICATION (REVIEW)

Introduction. Single-domain antibodies (nanobodies) are composed of the heavy-chain variable domain only. Compared to conventional immunoglobulins G (IgG) nanobodies have such qualities as: high bioavailability, ability to bind epitopes that are difficult to reach, high solubility and thermal stability, etc. Nanobodies can be easily manufactured in microorganisms (E. coli) to significantly save on cost.Text. Goal of the paper consists of the description of structural and functional properties of nanobodies and its effective application.Conclusion. Nanobodies can be used in many fields of medicine and biotechnology such as research, diagnostics and therapy of oncology, infectious, hematological, inflammatory, autoimmune and neurological diseases. They can also be easily modified using another nanobody, molecules or radioactive mark as necessary. Nanobodies have huge potential for applications in diagnostics, therapy and medicine