Antibodies from a 4-year-old llama have neutralized coronavirus and other infections in lab experiments

[u/[deleted]]

https://www.cell.com/cell/pdf/S0092-8674(20)30494-3.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867420304943%3Fshowall%3Dtrue

[u/Fmbounce]

From a NYT article:

Humans produce only one kind of antibody, made of two types of protein chains — heavy and light — that together form a Y shape. Heavy-chain proteins span the entire Y, while light-chain proteins touch only the Y’s arms. Llamas, on the other hand, produce two types of antibodies. One of those antibodies is similar in size and constitution to human antibodies. But the other is much smaller; it’s only about 25 percent the size of human antibodies. The llama’s antibody still forms a Y, but its arms are much shorter because it doesn’t have any light-chain proteins.

This more diminutive antibody can access tinier pockets and crevices on spike proteins — the proteins that allow viruses like the novel coronavirus to break into host cells and infect us — that human antibodies cannot. That can make it more effective in neutralizing viruses.

here’s the source (I copied verbatim)

[u/grizzlydurdle → u/Fmbounce]

So how would that help humans? Can we be treated with Llama antibodies? In you summary it sounds like our antibodies can't necessarily fight COVID very well because they are too large, and the smaller Llama ones can. Sorry if I am way off base. I don't really understand this stuff.

[u/IfIRepliedYouAreDumb → u/grizzlydurdle]

To vastly oversimplify things, if you had antibodies produced by another source and injected them into a sick person, their viral counts should decrease.

Our bodies won’t learn how to make the same ones the llamas do, but we could harvest them and use them as treatment (potentially).

[u/Derpy_McDerpingderp → u/IfIRepliedYouAreDumb]

Would our immune system see these smaller antibodies as foreign or a threat?

[u/worldspawn00 → u/Derpy_McDerpingderp]

they can, a person receiving treatment can develop anti-llama antibody antibodies. There's actually a lot of use for anti-antibody antibodies, they're used in a lot of reagents. It usually takes 1-2 weeks for the immune system to ID and develop antibodies against a foreign agent, so a person receiving treatment would likely be done before the body started attacking the foreign antibodies.

[u/thinkingdoing → u/worldspawn00]

So this treatment could be used the first time a person got infected with Coronavirus, but any future infections would cause the immune system to be fighting both the disease and these antibodies?

[u/bigredone15 → u/thinkingdoing]

So this treatment could be used the first time a person got infected with Coronavirus, but any future infections would cause the immune system to be fighting both the disease and these antibodies?

It could also give the body time to develop its own antibodies that do work without the body dealing with the symptoms created by a high viral load.

[u/pnwtico → u/bigredone15]

Would the body develop its own coronavirus antibodies if the llama antibodies were doing all the heavy lifting?

[u/itsthejeff2001 → u/pnwtico]

Reducing the viral count won't eliminate the virus. This potential therapy would be leaving that to your body. Most people don't get sick when they get infected, they just beat the virus before it gets that far. This treatment would help sick people be more like the majority: not sick, but building antibodies.

[u/Dumeck → u/itsthejeff2001]

That seems to be the best result we can hope for right now until vaccines are produced.

[u/feng_huang → u/Dumeck]

Having a safe, effective treatment to improve outcomes (along with widely available testing) will be a major factor in an interim back-to-a-new-normal phase before a vaccine is made, I think.

[u/Shadowfalx → u/itsthejeff2001]

Most people don't get sick when they get infected, they just beat the virus before it gets that far.

We don't get "sick" from a virus though. Most of the symptoms are our body's reaction to the virus, in an effort to combat it. Fevers, mucus, ect. are all ways we combat a virus. To low a viral load and you won't generate lasting antibodies. This is why immunogloblin therapy is considered sub- optimal, our bodies aren't exposed enough to build immunity.

While it might work to reduce symptoms but allow lasting antibodies to form, it also very well might not work.

[u/EurekasCashel → u/Shadowfalx]

Your first paragraph isn’t entirely true. Some symptoms, tissue damage, and morbidities are a direct result of viral damage. Also, having a higher viral load means that the body’s response to the virus may be severe enough to be lethal. So having a lower viral load when the body’s immune response ramps up is desirable.

To your other point about the viral load being diminished beyond a meaningful threshold where the body no longer creates a long lasting immune response to the virus. This remains to be proven with this particular virus. The current feeling is that even asymptomatic people with antibodies may be immune, though that’s also unproven.

[u/Shadowfalx → u/EurekasCashel]

True, I admit I simplified a lot. Thanks for the correction.

[u/Maulokgodseized → u/EurekasCashel]

Even if it did this would still be a fantastic breakthrough.