A groundbreaking new study published in the journal Science Translational Medicine is announcing the development of a novel mRNA-based vaccine designed to help resist tick bites. Preclinical testing in guinea pigs indicate the vaccine helps the immune system in recognizing tick bites, resulting in the parasites being dislodged before they can transmit any pathogenic disease.
Over a dozen serious diseases can be transmitted by tick bites. The most well-known is Lyme disease, caused by a bacterium called Borrelia burgdorferi. In the past, vaccines have successfully been developed to specifically target this Lyme disease bacterium. However, this prospective new vaccine takes a different approach, using mRNA technology to target the tick itself.
The vaccine is based on the same mRNA technology that led to the immensely successful rapid development of COVID-19 vaccines in 2020. But instead of directing cells in the body to produce spike proteins to train the body to attack SARS-CoV-2, this particular vaccine directs cells to produce a number of proteins found in the saliva of the black-legged tick Ixodes scapularis.
Dubbed 19ISP, the mRNA vaccine contains directives for 19 different proteins found in the tick saliva. The preclinical research successfully demonstrated the mRNA vaccine on a number of guinea pigs.
“We found that guinea pigs vaccinated with 19ISP developed skin redness after they were bitten, indicating that their immune system was activated and brought inflammatory cells to the site to fight off infection,” explains Andaleeb Sajid, co-first author on the study. “Like other animals that developed tick immunity after repeated bites, the ticks were not able to feed on the guinea pigs and quickly detached.”
As well as demonstrating the vaccine inducing an immune response quickly at the site of a tick bite, the researchers found the vaccinated guinea pigs also resisted infection with the Lyme disease bacterium when confronted with ticks carrying the pathogen. Sajid says this indicates a vaccine aimed at resisting tick bites could be sufficient to prevent most tick-borne diseases.
Human clinical trials testing this novel vaccine may still be a few years off as this introductory research offered some curious caveats. While the vaccine proved effective in guinea pigs the researchers found the vaccine was not effective at inducing tick immunity in mice.
It is not clear exactly why this may be the case but mice are a natural pool for ticks so the researchers theorize that the parasites could have evolved different ways to co-exist with the animals. Future studies in other animals will be needed to better understand how tick immunity can be produced in different hosts.
Senior author on the new study Erol Fikrig says this vaccine is different in the way it targets a carrier of a pathogen rather than the pathogen itself. This means it should offer a broad-based protection from all kinds of tick-induced disease and not just a single pathogen.
Fikrig speculates the way the vaccine could work in humans is by offering signs to a person they have been bitten by a tick soon after the tick has taken hold. This allows a person to quickly remove the tick before it can transmit any disease-causing bacteria or virus.
“The vaccine enhances tick recognition, partially turning a tick bite into a mosquito bite,” says Fikrig. “When you feel a mosquito bite, you swat it. With the vaccine, there is redness and likely an itch so you can recognize that you have been bitten and can pull the tick off immediately, before it has the ability to transmit B. burgdorferi.”
Read more about ticks found in New Jersey HERE.
The new study was published in the journal Science Translational Medicine.