A research team led by the Fisabio Foundation has demonstrated that dermcidin, an antimicrobial peptide naturally produced by the human body, also possesses anti-influenza virus activity.
The study also shows that people who do not show flu-like symptoms have higher baseline levels of this molecule (an antimicrobial protein that is naturally and continuously secreted from the sweat glands in human skin. It acts as a "natural antibiotic" that forms the first line of defense to protect the skin from infection), which may be associated with a reduced susceptibility to infection.
Dr. Maria Ferrer, a researcher with the Miguel Servette Program and head of the Antimicrobial Peptides and Diabetes Biology Group at the Fisabio Foundation, who led this study, explains: "Dermcidin, found in sweat and known for its antibacterial and antifungal activity, also shows anti-influenza virus activity and can interfere with infection, as we have observed in laboratory and animal models."
Dr. Alex Mira, a researcher at VesaBio and head of the Oral Microbiome Group, who co-led the study, notes that "these results show that our bodies have natural mechanisms capable of suppressing viral infections, which opens the door to the development of new, more effective antiviral drugs."
Researchers from the CIBERESP Center, the Biomedicine Institute of Valencia (IBV-CSIC), the CIBERER Center, the Institute for Research, Development and Innovation of Health Biotechnology in Elche (IDiBE) of Miguel Hernandez University, the University of Valencia, and the Margarita Salas Center for Biological Research (CIB-CSIC), as well as other international centers, also contributed to the study.
The study demonstrated that dermcidin works by binding to hemagglutinin — a protein essential for the influenza virus to enter the cell — at a key, highly conserved region involved in the fusion process.
This interaction triggers a conformational change in the viral protein that weakens the virus's ability to fuse with the cell membrane, thus preventing infection. In this way, dermcidin disrupts the virus before it can infect the cell, through a previously unknown mechanism of action.
This method of action contrasts with most available antivirals, which target another viral protein called "neuraminidase," to which resistance is beginning to appear.
Dr. Ferrer explains: "By working on regions of the virus that are virtually unchanging between subtypes — known as highly conserved regions — dermcidin can contribute to defense against different strains of the influenza virus."
In this context, Dr. Mira adds: "This same principle could apply to other respiratory viruses, such as measles virus and common cold-related coronaviruses, suggesting the possibility of a widespread effect."
The team found that dermcidin is present not only in sweat, but also at key entry points for respiratory viruses into the body, such as the nasopharynx, saliva, and tears.
Dr. Paula Correll, the study's lead researcher and a member of the team, explains: "The results show that baseline dermcidin levels are up to six times higher in people without flu-like symptoms, compared to susceptible individuals." Furthermore, its concentration increases significantly during respiratory infections.
Dr. Correll adds: "Overall, these results reinforce the idea that dermcidin is part of the first line of defense of the innate immune system against this type of infection."
Researchers indicate that dermcidin represents a promising candidate for developing new strategies to combat respiratory viral infections.
In addition to its direct antiviral activity, the team is investigating whether dermcidin may also play an immunomodulatory role, helping to regulate the immune system's response to infection.
These findings open up new research avenues for developing antiviral agents based on the body’s natural molecules that act on highly conserved viral regions, potentially reducing the likelihood of resistance development and enhancing their effectiveness against many respiratory viruses.
