Researchers from Novosibirsk State University and their colleagues from Biysk, Novosibirsk and Tomsk, used the newly developed type B influenza virus strain (strain B / Novosibirsk / 40/2017-MA) to study the therapeutic and prophylactic efficacy of antiviral drugs in vitro and in vivo. Their results were published in the Russian journal “Infectiology”.
Influenza B virus belongs to the Orthomyxoviridae family that consists of six genera that differ in a number of environmental, epidemiological, and structural characteristics. The first three genera (Influenzavirus A, Influenzavirus B, Influenzavirus C) are abbreviated A, B and C. According to published data, Type B virus (influenza B virus, FLUBV) has only been isolated in humans and seals. Infections caused by FLUBV can develop into serious respiratory illness, especially among primary school children (5–8 years).
Elena Prokopieva, Candidate of Biological Sciences, Associate Professor of Basic Medicine at the V. Zelman Institute of Medicine and Psychology and Senior Researcher at the NSU/FRC FTM Laboratory of Molecular Pathology, explained the importance of this study,
Recently, special attention has been paid to the influenza B virus. It has important epidemiological significance, especially among children, because there is an annual seasonal increase along with the influenza A virus.
In the 2004–2011 epidemic seasons (with the exception of the 2009 pandemic), 22 to 44% of all deaths associated with childhood influenza in the United States were caused by influenza B. In Europe, in the 2017–2018 epidemic season, the proportion of diseases caused by the influenza B virus accounted for 63% of all influenza cases. It is also known that in the 2017/2018 season, there was a mismatch between the vaccine and circulating strains of influenza B that led to a decrease in the effectiveness of vaccination, especially for children.
Influenza viruses are highly variable in vivo, leading to uncontrolled viral infections that are detrimental to public health and the economies of countries around the world. The continuous circulation of influenza viruses, the constant mutation of the genome and high contagiousness lead to the emergence of viruses with new properties.
Prokopieva described the relevance of their work,
This is why the flu virus with a new set of genes causes zoonoses, epidemics, and pandemics. From an immunological point of view, this tactic allows the virus to persist for a long time, since the susceptible population does not have immunity against it. Therefore, it is extremely important to study relevant antigenic strains of influenza viruses.
The adaptation of the influenza B virus obtained by Siberian scientists has already been used in preclinical studies of innovative drugs that are currently undergoing clinical trials. It was possible to simulate a non-lethal influenza infection in experimental animals with pronounced clinical signs of the disease using a strain of adapted influenza B virus. It provides the closest picture of the pathology, similar to that observed in humans infected with influenza B virus. This helps researchers evaluate the therapeutic and prophylactic efficacy of antiviral drugs in vivo and in vitro, as well as to study the effectiveness of vaccines.
Prokopieva concluded,
Our plans are to expand the range of possible uses of this strain and use influenza mouse models as an additional tool for predicting the effectiveness of a vaccine against circulating strains and evaluate a drug’s efficacy against influenza.
