Newly Identified Tick Protein Could Help Block Disease Transmission

Ticks transmit a wide range of viruses and bacteria that affect people, livestock, wildlife, and pets around the world, and tick-borne diseases continue to increase globally. Current prevention strategies largely rely on avoiding tick bites or reducing tick populations. A new study published in The EMBO Journal points toward a different kind of approach—one that targets the biological machinery ticks use to feed and transmit pathogens in the first place.

The research, led by Hameeda Sultana and Waqas Ahmed at the University of Tennessee College of Veterinary Medicine, centers on a tick protein found within exosomes—tiny membrane-bound particles that transport proteins and other biological signals between cells and tissues. "Exosomes are tiny bubble-like vesicles with messages in them," Sultana explained. When a tick bites a host, its saliva contains exosomes carrying a range of molecules that help the tick feed undetected while avoiding triggering the host's immune defenses.

Sultana's laboratory was the first to identify exosomes derived from tick saliva and salivary glands, work conducted between 2018 and 2020. The team found that ticks produce an exosomal glycine-rich protein that plays a role in feeding and virus transmission. "They contain several arthropod proteins that could facilitate tick feeding, pathogen acquisition from infected hosts to naïve ticks, and transmission of pathogens from infected ticks to naïve hosts," Sultana said.

When the researchers used genetic tools to silence the gene responsible for this protein, the effects were notable. Ticks lacking the protein struggled to feed effectively, showed reduced body weight after feeding, and had significantly lower virus levels—suggesting the protein plays a meaningful role in both feeding success and pathogen transmission.

The findings point toward what is known as a transmission-blocking vaccine—an approach that targets a molecule in the tick rather than the pathogen itself, with the aim of preventing the tick from successfully feeding or transmitting disease. "Targeting this type of protein might be an ideal approach to affect transmission of several pathogens from ticks," said co-senior author Girish Neelakanta.

"Since the identification of exosomes from ticks from my laboratory, several studies—including our own—have emphasized the importance of these vesicles in tick feeding and interactions with pathogens," Sultana said. "This is an exciting area of research that could open several avenues for the development of arthropod exosome-based strategies to target vector-borne diseases."