How the New Vaccine — For Bees — Works

Sam Westreich, PhD

Yes, we’re vaccinating bees, but it won’t solve all our pollination problems

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The real challenge is getting the tiny little Band-Aid to stick to those hairy little legs.Photo byPhoto by Michael Milverton on UnsplashonUnsplash

For a tiny insect, bees are vitally important to many aspects of our daily life, even if you don’t enjoy a bit of honey in your tea.

About a third of all the food we eat is produced from plants that are pollinated by bees. This includes apples, melons, cranberries, pumpkins, squash, broccoli, almonds, and more. Bee keepers have turned their hives into a resource, often taking them on the road to bring them from orchard to farm to field, ensuring that crops across the country get pollinated and produce fruit.

But recently, commercial honeybees have been under attack by a dangerous bacterium. This bacterium is named Paenibacillus larvae, and it causes a disease in bees known as American Foulbrood. The bacterium infects the bee larvae, growing in their guts until the sheer mass of bacteria bursts out of the larvae, killing it in the process. It spreads rapidly through a hive, and the only solution for beekeepers has been to burn the entire hive…

…until now. Now, we might have a vaccine.

Here’s how the vaccine works, how it’s provided to the bees — and why it’s not going to solve all our problems.

How to vaccinate a bee

As mentioned above, American Foulbrood is a nasty disease; it’s highly infectious and it rips through a hive, transforming all of the bee larvae into little more than brown, bacteria-filled goo. It doesn’t hurt adult bees, but the hive has no chance of survival without any offspring.

Researchers have looked at some treatments to kill off P. larvae, such as by deploying bacteria-targeting viruses into the hive. But these methods aren’t guaranteed to kill all of the bacteria, and even just a few bacteria slipping by can still destroy the hive.

This latest approach is different; it makes use of a bee’s own immune system to teach the bee larvae how to fend off the bacterium. If the bee larvae can kill the bacterium, they won’t be taken over and will survive to adulthood.

Dalan Animal Health, the company behind this vaccine, states that it uses a dead version of the bacterium. And, unlike COVID and most vaccines that we humans receive, this vaccine is given orally.

That’s right, no need for tiny bee-sized needles! The dead bacterium is incorporated into royal jelly, the food source that feeds the queen bee. The queen bee is able to create an immune response to the bacterium, even though it’s no longer alive — and furthermore, passes down that immunity to all of her offspring. Thus, once a queen bee is immunized, all of her descendants should also be safe.

No antibodies for these bees

One reason why it’s been so difficult to make a vaccine for bees is because, in comparison to humans, bees have a much simpler and less versatile immune system.

When we talk about our immune system, we usually talk about two different sides of it; we have our innate immune system, and our adaptive immune system.

Our innate immune system is shared with most other creatures, including honeybees. This is the system that responds immediately to threats. We’re all born with innate immune responses, and it acts fast. It includes a bunch of responses, such as:

  • barriers and clotting to help minimize wound damage
  • immune cells that destroy anything identified as foreign
  • defenses inside cells that detect foreign DNA or proteins

This innate system is a good first line of defense, but it’s not really customizable. It’s got a limited repertoire of tools, and lots of viruses and bacteria have found clever ways to circumnavigate it.

For us humans, that’s no problem, since we can fall back on our adaptive immune system. This is the slower-acting but much more complex system; it includes the ability to learn to recognize bits of pathogens, say “yep this is foreign”, and create custom-targeted molecules called antibodies that seek out and attach to those foreign bits. Antibodies are like a homing beacon, locking onto invaders and calling out “I’m a bad guy, eat me!” to the rest of our immune system.

But bees don’t have an adaptive immune system. Bees can’t make antibodies.

So how do you teach a bee to fight a bacterium that isn’t killed by its innate immune response?

A 2015 scientific paper provides the answer. Bees and other insects do have some ability to recognize and target specific pathogens; they do so with a special protein, called vitellogenin. This protein recognizes certain patterns associated with P. larvae, the invasive bacterium, and lights the signal fire to start an immune response.

And even better, vitellogenin is passed down from a mother insect to her offspring in the eggs she lays.

It’s important to note that this vaccine approach does not make any changes to the DNA of the bees themselves. There’s no genetic modification going on here! This is merely making use of a memory-holding protein already in bees, that can identify P. larvae, and giving it to a whole hive to be passed on and carried for defense.

This vaccine won’t solve many bee-related challenges

This intervention is a great first step. There’s a reason why the FDA has granted it a conditional license; this is provided by the government agency for emergency situations. We need to protect our honeybees, since they play such a pivotal role in pollinating our crops.

But honeybees aren’t the only bees out there in the world. Honeybees hit up a lot of commercial crops, but there are a ton of other plants that are also dependent on bees for pollination.

There are over 20,000 species of bee in the world, and 4,000 of those are native to the United States/North America. Many of these bees are solitary, living on their own instead of in a communal hive, and a decent number of them haven’t even been fully identified yet!

These native bees don’t just fertilize native flowers and other plants; they even fertilize a number of crops, often with greater efficiency than honeybees. For example, plants like tomatoes and squash, which are native to North America, are better fertilized by native bees than by honeybees.

Wild bees also have to deal with P. larvae, although there’s some evidence that wild solitary bees may be better at fighting off this disease than honeybee colonies. Still, this vaccine isn’t going to be able to help solitary bees with their own battles.

The bigger threats to native bees include loss of habitat and the continued use of pesticides, specifically a class of pesticides called neonicotinoids. These pesticides are incorporated into the entire plant, including in its pollen — meaning that, even if a plant wasn’t sprayed recently, it incorporates the pesticide and still provides toxic pollen to any bee stopping by.

Neonicotinoids are still the most widely used pesticide in the United States, used on an estimated 30% of all soybean crops and 79% of all corn crops. Their use is banned in Europe, some areas of Canada, Maine, and New Jersey, but most states still allow them.

In summary: special proteins help us protect honeybees from disease, but it won’t help native bees

If this new method of protecting commercial honeybees works — and it’s promising so far, but there’s still more evaluation to be done — it could be a big step in helping us better fight insect pathogens.

Since insects don’t have adaptive immunity and don’t make antibodies against diseases the way that we do, it’s harder for them to fight diseases. But as we learn more about how their cells remember and identify attacking bacteria, we can better build and spread targeted cures.

However, we do need to keep in mind that this, on its own, won’t help all the bees. We need to pair these scientific advances with similar advances in preserving habitat, native species, and limiting our pesticide use, in order to also help save many of the thousands of local, solitary bee species that do a lot of the hidden lifting to keep up our diverse plant world around us.

If you want to do more to help bees? Consider stopping the use of pesticides, if you use any, and lobby your Congressional representative to push for legislation that bans or further limits the use of neonicotinoid pesticides.

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A microbiome scientist working at a tech startup in Silicon Valley, Sam Westreich provides insights into science and technology, exploring the strangest areas of biology, science, and biotechnology.

Mountain View, CA
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