Scientists have long struggled with finding effective ways to fight back against viral infections. An international investigation led by a team from RMIT in Melbourne has uncovered a previously undiscovered biological process that suppresses the body's natural antiviral response. This research could lead to entirely new treatment strategies for some of the world's most widespread viruses, including the common cold and the flu.

While we currently use antibiotics to treat bacterial infections, those drugs are not helpful when the body is attacked by a virus. Generally when one is struck down by a virus the treatment is to rely on the immune system to kick in and fight back. We currently have two standard ways to fight viruses: antiviral medications, taken within the first day or two of infection, or vaccines, that stimulate immune production of antibodies.

In searching for a new front to fight viral infections, the researchers discovered a 1.5 billion-year-old biological process whereby a virus triggers a protein that subsequently suppresses the body's natural antiviral response.

This protein is called Nox2 oxidase, and it has previously been found to play a role in stimulating the immune system to attack and kill pathogens such as bacteria and fungi. In this new research, scientists discovered that the Nox2 oxidase protein actually enhances the effects of viral attacks instead of inhibiting them.

The researchers then developed a targeted drug that could restrain the activity of Nox2 oxidase. In a study with mice they found the drug was effective in suppressing the effects of an influenza infection.

"We have identified a protein of the immune system that contributes to the disease caused by flu viruses irrespective of their strain," says Dr Stavros Selemidis, one of the senior authors on the project. "We also developed a novel drug delivery system to target this protein, which drastically alleviated the burden of viral disease."

The research raises the question of why this process could have evolved in the first place when it clearly causes the mammalian body harm. The researcher's hypothesize that this mechanism, stimulated by the Nox2 oxidase protein, evolved to aid the body's natural autoimmune response. The idea is that this natural mechanism exacerbates the viral pathogenicity to allow the body to ultimately generate a comprehensive autoimmune response.

The study also suggests that suppression of the Nox2 oxidase protein in the context of a short-term treatment would not cause long-term problems with the body's autoimmune response.

The discovery could lead to new antiviral treatments, with applications across a variety of viral diseases, from the flu to dengue and HIV. It also directs researchers to a new understanding of how a virus gains its foothold within the human body, meaning new treatment strategies could maintain a high efficacy in the face of new or mutating viral outbreaks.

The study was published in the journal Nature Communications.

Source: RMIT

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