Tick Protein That Blocks Two Chemokine Classes Could Lead to New Autoimmune Therapies

Ticks are remarkably effective parasites. They can feed on a host for days without triggering the immune response that would dislodge them - an ability that depends on a collection of proteins they secrete to suppress host immunity. Among the most important of these proteins are evasins, which work by binding to and neutralizing chemokines: the small signaling molecules that direct immune cells toward sites of infection or injury.

When chemokines malfunction - overstimulating the immune system rather than calibrating it - the result can be conditions like rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, and certain cancers. The pharmaceutical logic of studying tick evasins is therefore straightforward: if these proteins evolved to shut down chemokine signaling in a living host, they might be adapted into therapeutics that do the same in patients with inflammatory and autoimmune conditions.

Until now, researchers had found only evasins that work within a single chemokine class, either blocking CC chemokines or CXC chemokines but not both. These two major classes use different receptor families and drive different aspects of inflammatory signaling. A team at the Monash University Biomedicine Discovery Institute, led by Professor Martin Stone and Dr. Ram Bhusal, has now identified a naturally occurring evasin that bridges this divide.

What the discovery changes

The finding, published in Cell Press, overturns an assumption about how ticks suppress immunity. The previous model held that ticks deploy a cocktail of evasins, each targeting a specific chemokine class, with the combined effect shutting down the broader signaling network. "However, in this study, we have identified a naturally occurring evasin that can inhibit both major classes of chemokines," said co-first author Mr. Kunwar. "This is a novel finding and represents a significant advance in the field."

A single molecule capable of broad-spectrum chemokine inhibition simplifies the therapeutic picture considerably. Rather than developing and delivering combinations of narrow-spectrum blockers, a drug based on this dual-class evasin could potentially address the full range of chemokine-driven inflammation with one agent.

Dr. Devkota, the other co-first author, pointed to the practical therapeutic implications: "The discovery opens up new opportunities to develop therapies that target chemokines driving inflammatory diseases such as RA and MS. While treatments are available, there remains a significant need for therapies that more effectively prevent disease progression."

The challenges ahead

The path from a discovered protein to an approved therapeutic is long and uncertain. The current work establishes the binding activity and dual-class specificity of the evasin, which is a meaningful early step. Several things remain to be demonstrated: whether the protein can be produced reliably at pharmaceutical scale, how it behaves in animal models of the target diseases, what its safety profile looks like when administered chronically, and whether its activity is specific enough to suppress harmful inflammation without impairing beneficial immune responses that the body needs for infection defense.

Tick-derived proteins also face the biological challenge of potential immunogenicity - the host immune system recognizing the foreign protein and mounting a response that neutralizes it or causes adverse reactions. This is a known obstacle in protein therapeutics and would need to be addressed through protein engineering if the evasin is to serve as the basis for a drug.

What the discovery provides is a clear new target and a natural scaffold to work from. The dual-class specificity defines a mechanism that chemists and structural biologists can study, modify, and potentially optimize into something stable and manufacturable. Given the ongoing unmet need in conditions like progressive MS and treatment-resistant rheumatoid arthritis, the research direction is clinically well-motivated.