A new vaccine that teaches the immune system to recognize saliva from tick bites could prevent people from getting tick-borne diseases, according to a recent study.
Some animals that are exposed to tick bites are able to develop resistance to tick feeding, where the ticks detach soon after biting or cause skin redness that alert the host to remove them. Several animals that don't typically serve as hosts to ticks have been observed by scientists.
In laboratory settings, guinea pigs are able to develop robust immunity against ticks. People who have been exposed to ticks a lot can get itchy skin, a symptom that may be associated with tick immunity.
The lab was curious if we could induce tick immunity. We developed a vaccine called 19ISP that teaches cells to recognize the 19 selected proteins in the saliva of Ixodes scapularis, also known as the deer or black-legged tick, which leaves on the skin during a bite.
Our vaccine targets the saliva of the tick rather than the invading pathogen's saliva.
We found that the immune system of the guinea pigs was activated after they were bitten and that they recruited inflammatory cells to fight off the infection.
The ticks were unable to feed on the guinea pigs because of their tick immunity. The vaccine-vaccinated pigs were tested for Borrelia burgdorferi, the bacterium that causes the disease. Almost half of the non-vaccinated guinea pigs tested positive for Borrelia.
Why it matters.
There are almost 40,000 reported cases of tick-borne diseases in the US.
There are dangers to farm workers and anyone outdoors from ticks. Several other pathogens can cause serious and potentially life-threatening conditions if they are transmitted by ticks.
The 19ISP vaccine was able to cause resistance to the pathogen that causes the disease in the first place, unlike traditional vaccines, which cause resistance to the pathogen in the first place.
Our study suggests that this form of tick-based vaccine may be sufficient to prevent infections.
We have found that mice do not have the same immunity as guinea pigs. We plan to use this vaccine model in other animals to better understand how immunity varies in different tick hosts.
We plan to develop vaccines for other tick-borne pathogens and test for immunity to different tick species.
Our hope is that the vaccine can be applied to other diseases.
tick bites and mosquito bites are different in how they are fed. Vaccines may need to be changed for each disease-carrier because they may be different.
What's next?
We want to see if people who have already been exposed to ticks have developed an immunity to 19ISP. Clinical trials testing the vaccines in people may eventually follow after this clarification of how tick immunity works.
Andaleeb Sajid is a staff scientist at the National Institutes of Health.
The Conversation's article is a Creative Commons licensed one. The original article can be found here.
