University of Barcelona Study Identifies Polμ Protein as Vital Safeguard for Immune Cells During Severe Infection

University of Barcelona researchers find Polμ protein protects immune cells from DNA damage. Discovery could lead to new treatments for chronic inflammation.

By: AXL Media

Published: Apr 29, 2026, 6:49 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Biological Sentinel of the Innate Immune System

When the human body encounters a wound or a pathogen, it immediately deploys an inflammatory response as its primary line of defense. Central to this process are macrophages, specialized cells of the innate immune system tasked with neutralizing infectious agents and initiating tissue repair. New evidence from the University of Barcelona reveals that the success of this recovery phase depends on a specific protein known as Polμ. Without this protein, the very cells meant to protect the body are unable to survive the harsh environment of an active infection site, potentially leading to persistent tissue damage and systemic failure.

Mitigating Collateral Damage from Reactive Oxygen Species

The process of destroying pathogens requires macrophages to produce reactive oxygen species, which act as a chemical weapon against external threats. However, these volatile molecules do not discriminate between the invader and the host cell, often causing significant DNA damage to the macrophages themselves. According to researchers Jorge Lloberas and Antonio Celada, the Polμ protein serves as a critical repair mechanism that allows these defense cells to endure their own chemical environment. In the absence of this polymerase, the repair of genetic damage stalls, resulting in the premature death of macrophages and a breakdown in the transition from inflammation to healing.

Proving Protein Essentiality Through Animal Model Analysis

To understand the specific role of Polμ in the immune cycle, the research team utilized animal models with a specific protein deficiency. By observing skin inflammation and muscle injuries in mice lacking Polμ, lead author Carlos Batlle-Recoder and his colleagues demonstrated that both the initial attack phase and the subsequent repair phase of inflammation were fundamentally defective. The study shows that the loss of this protein compromises the physical survival of immune cells in vivo, providing the first clear link between Polμ activity and the functional lifecycle of macrophages during a lived immune response.