King's College London

Most antiviral medicines and vaccines are designed to target specific viruses, meaning they are often developed only after a new virus has emerged. This reactive approach can leave populations vulnerable during the early stages of outbreaks.

In a new study published in Angewandte Chemie, the researchers took a different approach by looking to the body's innate immune system which is our first line of defence against infection.

The team focused on a naturally occurring antiviral enzyme called RSAD2, also known as Viperin, which helps cells produce molecules that stop many viruses from replicating. Although scientists have studied the enzyme for many years, it was not known how it obtains the electrons it needs to function inside cells.

Using a combination of scientific techniques, the researchers identified the partner protein that supplies these electrons, solving the question around how this natural antiviral defence works. This finding unlocks new host-directed antiviral strategies that target cellular pathways rather viruses. They have the potential to minimize viral resistance, provide broad-spectrum efficacy, and help manage severe inflammation.

They then combined the enzyme with its partner protein to create a self-sufficient version that can work on its own. This is a step forward because these new enzymes do not need any cellular partner and will not interfere with other natural biological processes requiring electrons, whose movement are the primary source of energy. In the future, mRNA technology could be used to deliver the coding sequence of the enzyme, enabling cells to produce it. The enzyme will then enable individual cells to produce its own antiviral molecules to block viral reproduction machinery and help fight viral infections.

This approach could offer several advantages over conventional antiviral drugs. Rather than taking tablets over several days, patients could one day receive a single treatment that enables their own cells to generate antiviral molecules. Because it is based on the body's natural immune defences, it may also help protect against new or emerging viruses.

As the technology relies on the body to produce the therapeutic itself, manufacturing costs and environmental impact could be reduced. This contrasts with conventional antiviral therapies, which can release hundreds of kilograms of carbon dioxide per dose into the atmosphere.

Dr Kourosh Ebrahimi, Senior Lecturer in Immunology and Drug Discovery and senior author of the study, said: "Viral infections remain a major global challenge, yet most antiviral drugs and vaccines are designed to target specific viruses, meaning we are often responding only after a new virus has emerged."

The next stage of the research will involve testing the engineered enzyme against multiple viruses in cell and animal models. If successful, the approach could eventually progress to clinical trials as a potential new strategy for preventing and treating viral infections.