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In addition to providing us with delicious honey, the hardworking honey bees also pollinate about a third of food crops and almost 90 percent of wild grasses, like alfalfa, used to feed livestock. Hence, it is not surprising that their declining population, caused by climate change, habitat loss, and deadly microbial diseases, has researchers scrambling to find ways to protect the vulnerable insects, which are so crucial to our existence. Now, scientists from the University of Helsinki in Finland have found a way to help honey bees fight off infectious diseases with a sweet, edible vaccine!
Vaccinating non-humans is not a novel idea. Domesticated dogs and cats have been inoculated against rabies, Lyme disease, and even the flu for many years. However, using them to protect insects has never been considered possible. That’s because vaccinations entail injecting a dead, or weakened, version of the virus into the body and allowing the immune system to create antibodies to fend off the disease. Since insects do not possess antibodies, they lack a "memory" for fighting infections and therefore do not benefit from traditional vaccinations.
Dalial Freitak, a biologist at the University of Helsinki, came up with the idea of an edible insect vaccine in 2014, after observing that when a moth was fed certain bacteria, it was able to pass on immunity to its offspring. Meanwhile, her colleague, Heli Salmela, had noticed that vitellogenin, a bee protein, appeared to have a similar effect to invasive bacteria in bees.
"So they could actually convey something by eating. I just didn't know what the mechanism was. At the time, as I started my post-doc work in Helsinki, I met with Heli Salmela, who was working on honeybees and a protein called vitellogenin. I heard her talk, and I was like: OK, I could make a bet that it is your protein that takes my signal from one generation to another. We started to collaborate, got funding from the Academy of Finland, and that was actually the beginning of PrimeBEE," Freitak explains.
The first PrimeBEE vaccine, which is still undergoing safety tests, aims to protect honeybees against American foulbrood, or AFB, an infectious disease which affects bee colonies worldwide. The harmful bacteria, introduced to the hive by nurse bees, feed on larvae and generate spores which spread and infect the entire hive. “It's a death sentence for a hive or colony to be diagnosed with the disease,” says Toni Burnham, president of the D.C. Beekeepers Alliance in Washington.
The researchers, who unveiled their findings on October 18, 2018, say the vaccine teaches honeybees to identify harmful diseases, similar to how antibodies function in humans and animals. They explain, "When the queen bee eats something with pathogens in it, the pathogen signature molecules are bound by vitellogenin. Vitellogenin then carries these signature molecules into the queen's eggs, where they work as inducers for future immune responses." The researchers believe that once the first PrimeBEE vaccine is perfected, defense against other pathogens will be easy to create.
“We need to help honey bees, absolutely. Even improving their life a little would have a big effect on the global scale. Of course, the honey bees have many other problems as well: pesticides, habitat loss and so on, but diseases come hand in hand with these life-quality problems,” Freitak says. “If we can help honey bees to be healthier and if we can save even a small part of the bee population with this invention, I think we have done our good deed and saved the world a little bit.”
Resources: Smithsonianmag.com, NPR.org, mnn.com.