Never again flu? Influenza virus replication was completely blocked

Flu soon a disease of the past?

Every year, especially in winter, many people get sick with the flu. A way has now been identified to stop a strain of the flu virus from replicating in cells. This finding could lead to highly effective treatments for the flu and other respiratory viruses such as SARS-CoV-2.

A new study involving experts from the University of California at Riverside found that the so-called SUMOylation inhibitor STE025 is able to completely block the replication of the influenza B virus. This offers new options for the development of antiviral therapeutics.

The results were published in the English-language journal Viruses.

Older people particularly at risk from influenza

Getting sick with the flu isn’t exactly pleasant, but it usually doesn’t have life-threatening effects. Nevertheless, many people die every year as a result of the flu, with the highest risk of severe courses and deaths being older people, according to the experts at the Robert Koch Institute (RKI).

Deaths from flu in Germany

The number of deaths can vary greatly in individual influenza outbreaks. In Germany, for example, there were sometimes only a few hundred deaths during the flu season, but also over 25,000 deaths in the 2017/18 season alone, the RKI doctors add.

Effectiveness of influenza vaccines

Flu vaccines, in which the body’s immune system learns to recognize and fight the virus when it enters the body, are not always effective, the researchers involved in the new study report in a press release.

The reasons for this are not fully understood, but it is thought to be probably related to the complexity of the immune system and viral mutations.

How does influenza progress?

In order to cause illness, the influenza virus must first infect cells in the body, where it then multiplies and infects other cells, the team explains.

It has been established in the past that the two most common types of influenza viruses (influenza A and influenza B) require a unique human protein to trigger the above process.

Blocked protein prevents influenza B virus from multiplying

In the new research, the experts have now succeeded in preventing the influenza B virus from multiplying by blocking this necessary protein. It was shown that without the protein, virus replication in the cells is completely prevented.

The influenza B virus uses a human cellular process called SUMOylation to manipulate the M1 gene, which plays various roles in the influenza virus life cycle.

The researchers have now discovered that a SUMOylation inhibitor called STE025 is able to completely block the replication of the influenza B virus.

Treatment may also be possible for influenza A

The influenza B virus treated with the SUMOylation inhibitor showed a lack of SUMOylation on the M1 protein and was unable to replicate in human cells, the team said.

Influenza A also has SUMOylated proteins and could therefore also be susceptible to the SUMOyaltion inhibitor, the experts say.

Eliminating influenza forever

Further research is needed to gain a better understanding of the dependence of influenza B on SUMOylation. Still, the finding that STE025 inhibits SUMOylation and prevents influenza virus replication is a big step forward in eradicating influenza once and for all, the team said. (as)