Immune ‘Traffic Controller’ CD44 Hijacked by Virus, Study Reveals

Researchers at Monash University and the Lions Eye Institute have identified a crucial protein, CD44, that functions as a central “traffic controller” for immune cells. Their discovery, published in Nature in 2026, reveals how this protein coordinates immune responses and, critically, how the cytomegalovirus (CMV) can exploit this system to suppress the body’s defenses.

A Central Regulator of Immunity

The research highlights CD44’s role in controlling a network of support cells – specifically, stromal cells – that are essential for efficient immune cell movement and communication. These stromal cells facilitate the exchange of information needed to combat infections, respond effectively to vaccines, and maintain overall health. The study demonstrates that CD44 is a “master regulator” of these processes.

How CMV Hijacks the System

The team found that CMV can produce a protein that blocks the function of CD44 on stromal cells. This disruption effectively derails the “traffic” of immune cells, weakening the body’s antiviral response. According to Professor Mariapia Degli-Esposti, Head of Experimental and Viral Immunology at Monash Biomedicine Discovery Institute and Head of Experimental Immunology at the Lions Eye Institute, this represents “a completely new way for a virus to target an immune response.”

Did You Know? Cytomegalovirus (CMV) is a common virus that can cause a range of symptoms, from mild illness to more severe complications, particularly in individuals with weakened immune systems.

Implications for Future Therapies

Dr. Chris Andoniou, a Senior Research Fellow at both institutes, suggests that understanding this viral mechanism could lead to the development of new therapies. Drugs inspired by the viral protein could potentially dampen harmful inflammation by precisely targeting CD44 activity. This approach could offer a way to manage and treat autoimmune conditions by safely reducing excessive immune activation.

Expert Insight: This discovery shifts the focus beyond directly targeting immune cells themselves. By understanding how viruses manipulate the supporting infrastructure of the immune system, researchers open up new avenues for therapeutic intervention, potentially offering more nuanced and effective treatments.

Professor Degli-Esposti uses an analogy to explain the system: “Think of the immune system like a busy city with millions of cells patrolling to keep us safe. CD44 acts as the central traffic controller; it keeps immune cells moving and coordinates their interactions at the right place and time.”

Frequently Asked Questions

What is CD44?

CD44 is a molecule that centrally controls the network of support cells, specifically stromal cells, that guide immune system function. It helps immune cells move efficiently and exchange information.

How does CMV affect CD44?

CMV produces a protein that blocks CD44 function on stromal cells, disrupting immune cell traffic and weakening the body’s antiviral response.

What are the potential therapeutic applications of this research?

Drugs inspired by the viral protein could be developed to dampen harmful inflammation, and potentially help manage and treat autoimmune conditions by reducing excessive immune activation.

Could a deeper understanding of CD44’s role in immune regulation lead to more targeted and effective treatments for a wider range of immune-related diseases?