Swedish researchers are looking for peptides to destroy viruses

A new study from Sweden shows how a peptide from lactic acid bacteria destroys viruses, including the coronavirus. The findings have resulted in a Swedish patent, with international patents pending.

“We expect a quick turnaround to allow this discovery to be used in antiviral medicine and as a complement to vaccines,” said Hazem Khalaf, lecturer and researcher in microbiology at Örebro University.

Khalaf and fellow researcher Torbjörn Bengtsson, post-retired professor of biomedical medicine at Örebro, were in charge of the research, which has been published by the National Library of Medicine. This research builds on previous studies of peptides as an alternative way to treat bacteria that have developed resistance to antibiotic drugs.

New variants of viruses that cause epidemics and pandemics pose a threat to global health. Typically, developing a new vaccine is a lengthy process – the COVID-19 vaccine being the exception – which increases the demand for antiviral drugs.

Which peptides have been used in research to destroy viruses?

The peptide used in this study was plantaricin (PLNC8 αβ). The researchers used the same basic concept as in previous bacterial studies published in Nature Scientific Reports. The starting point is that the peptide binds to the lipids in the viral membrane through electrostatic interactions.

“This lipid membrane is stable and does not mutate. But if the membrane is destroyed, the virus cannot attach to human cells to reproduce and cause disease,” said Bengtsson.

Plantaricin PLNC8 αβ has an effect on a broad spectrum of membrane-bound viruses, especially coronaviruses, influenza viruses, and flaviviruses.

Viral mutations

The virus mutates very quickly, which has become especially evident during the COVID-19 pandemic. Antiviral drugs given to those infected today target specific proteins contained in the virus. The problem is that these proteins can mutate, and if they do, antiviral treatment will have no effect.

In collaboration with the Innovation Office at Örebro University, the two researchers have had a Swedish patent granted for this invention and an application for an international patent is currently underway.

Next, the researchers will work closely with the pharmaceutical industry with the aim of developing a treatment.

“We might, for example, look at nasal sprays to be used in the early stages of infection, to prevent the virus from spreading to the lungs and prevent infected people from passing on the virus,” said Hazem Khalaf.

In order to enable rapid treatment, the infected person must know that the virus that has infected them is actually one with the membrane. Bengtsson says there are at-home tests available that can quickly determine whether the virus is “the right one” and not, for example, the common cold virus.

“In the future, we may all have these peptides in our bathroom cabinets – for immediate use against viral infections,” says Bengtsson.

He also pointed out that treatment of viral infections may have a dual action effect by also preventing and treating subsequent bacterial infections.

Virus type

There are two types of viruses. Naked viruses have a protein shell that encloses the genome. In other types, the protein shell is covered by a lipid membrane. It is this lipid membrane that is dissolved and destroyed by the peptides in this study.

Influenza viruses, RSV (respiratory syncytial virus) and coronaviruses, like the variants prevalent during the COVID-19 pandemic, are viruses covered with a lipid membrane. Flaviviruses, carried by ticks and mosquitoes and causing diseases such as tick-borne encephalitis (TBE), are another example.