This episode was filmed on May 19th, 2020. If we have more recent videos about the pandemic you can find them in our COVID19 playlist which we will link in the description.

In our last episode, of Sci Show News, we talked about how scientists are looking into whether the serum pulled from the blood of people who have recovered from Covid-19 can be used to help those who are currently infected. That's because it contains helpful immune proteins called antibodies. But if the stuff they got from Tom Hanks and company doesn't work, they may have another, albeit weirder, option.

You see, in May, scientists announced they'd found antibodies from a llama named winter that bind to this coronavirus. And there's some reason to think these antibodies might be better than any of the ones from people.

Antibodies are proteins made by the immune system. The ones swirling around in your blood right now are made of four strings or "chains" of amino acids. Two so-called heavy chains and two light chains. These are arranged in a Y shape and the amino acids at the tips of that Y are super variable. This allows your body to make different antibodies that are essentially customized to stick to the various things that it would like to get rid of, like toxins or viruses. 

When antibodies stick, they can act as a flag or sorts, telling other immune cells to kill the thing they're stuck to. Or, ever better, they can neutralize the invader, like by blocking the parts a virus needs to infect cells. All of this is why scientists have been looking for ways to use human antibodies to fight off the virus that causes Covid-19. 

But, they don't always work. Like, if an antibody binds to the wrong spot on a virus, it might not actually prevent the virus from doing its thing. And unfortunately, sometimes our antibodies can't reach or stick to the most effective spots. 

In 1989, scientists realized that the antibodies we have aren't the only kind out there. A student-run project was looking for a way to test camels and water buffaloes for sleeping sickness. And when they tested some camel serum their professor had in the freezer, they found a second kind of antibody. 

They're called single-domain antibodies, or heavy-chain-only antibodies because they have no light chains and are instead just one long heavy chain looped around itself. Because of that, they're about half the size of regular antibodies. And this leads to a number of interesting properties, like that they are more stable when exposed to heat. But it also means that they can fit into nooks and crannies that other antibodies can't. 

We know that all the animals in the camel family make these miniature antibodies, including llamas, and to be totally frank, we're not sure why. Maybe having them conferred an advantage against some ancient pathogen, or maybe they help the animals thrive in extreme heat or cold. But whatever the reason, from a medical standpoint, the stability, precision, and small size gives these antibodies a lot of potential. 

They've been investigated as therapeutics for a wide range of diseases, including cancer, HIV, and the flu. And one recently got approved by the FDA for treating a rare blood disorder. Which brings us back to Winter the llama, and how we might be able to use her single-domain antibodies to fight Covind-19. 

It just so happens that, long before the pandemic, an international team of researchers was looking to see if llama antibodies could attack the corona viruses behind SARS and MERS. So, they immunized on of their llamas, named Winter, with spike proteins from those two viruses. Spike proteins are the spiky-looking proteins that stick out from coronavirus particles and they're what actually grab onto our cells to start the infection process, so they're a good target for a neutralizing antibody. 

And indeed, previous work had shown that single-domain antibodies could gum up the spike proteins of the MERS coronavirus, preventing it from entering cells. But, no one had tried to develop them against the original SARS virus. So the team was pretty excited to find that after injecting Winter with those spike proteins, she produced mini-antibodies that could neutralize both viruses. And they were in the process of writing up their findings when January 2020 hit. 

With a new cousin of the corona viruses behind SARS and MERS spreading around the world, they decided to investigate whether these antibodies from Winter could attack it. And they seem to. The mini-antibody that blocks the virus responsible for SARS appears to work well against the virus that causes Covid-19. Which is really exciting, but there's still a lot of work to be done. 

Pulling serum from one llama isn't exactly going to be a sustainable way to obtain a medicine. Also it sounds unpleasant for Winter. So you might be thinking, just attach a llama farm to every hospital. That sounds great, but might be a little impractical. 

So they'll need to be sure they can make a lot of these antibodies on demand. Luckily, single domain antibodies are essentially one long protein instead of a couple stuck together, so it's pretty straightforward to get genetically-modified bacteria or yeast to manufacture them for you. The bigger obstacle might be getting everything ready for tests and then running those tests in people. The researchers think that'll take several months at least, probably more like a year. 

But if they prove safe and effective, these antibodies could help patients clear the infection more quickly, or even become a preventative treatment for people like healthcare workers. 

But see, these small antibodies don't stick around in the body super long. The kidneys can filter them out. But they're fairly shelf-stable and can be administered with an inhaler, so we could give them as a shield to those likely to be exposed to the virus like doctors and nurses. And even if the therapeutic angle doesn't pan out, the antibodies themselves might end up improving diagnostic tests. 

Some tests already use antibodies to detect the presence of a pathogen or a person's antibodies that target that pathogen. So it's possible llama antibodies could make more accurate or cheaper versions of those tests. And we could definitely use more accurate tests right now, since we're coming to realize that some of the ones we've got have high false positive or false negative rates. 

So, in sum, llamas are just the best. And by the way, Winter is just fine. One of the study co-authors has reassured everyone that she's living a happy life on a farm in Belgum. And if her antibodies pan out to be helpful to the human race, I really hope she gets a bunch of special treats or something, I don't know, what do llamas like?

Thanks for watching this episode of Sci Show News, which is produced by Complexly. Complexly also produces How to Vote in Every State, a guide to voting for US citizens. It's a pretty big election year, and if you want to have a voice in your government, and I don't know why you wouldn't, you'll want to vote. We've made a whole series of videos explaining how to vote in each state, as well as advice for special cases like territories and over-seas voters, and also how to know what's going to be on your ballot before you vote. You can check out our 2020 guide at youtube dot com slash how to vote in every state.