
Clues to Covid-19 coronavirus’s vulnerability emerge from antibody against SARS - kungfudoi
https://www.scripps.edu/news-and-events/press-room/2020/20200403-wilson-covid19.html
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kmlevitt
>”Despite the slightness of difference between the two coronaviruses, the
antibody binds much less tightly to SARS-CoV-2 than it does to the SARS virus,
and cannot neutralize SARS-CoV-2 in lab dish tests as it does SARS-CoV.”

Oh.

~~~
AstralStorm
There are different antibodies being tested though. So there's a good chance a
properly working mAb (not inducing Antibody Dependent Enhancement) will
happen.

~~~
AnotherGoodName
Can anyone chime in why we're not simply looking at antibodies from those who
have now recovered?

~~~
throwaway1777
We are. Many avenues are being explored by different teams.

[https://www.jsonline.com/story/news/2020/04/03/promising-
use...](https://www.jsonline.com/story/news/2020/04/03/promising-use-plasma-
coronavirus-survivors-reaches-trial-stage/2945671001/)

~~~
AnotherGoodName
Yeah the real confusion for me is why even bother looking at anything other
than these actual existing SAR-2 antibodies.

"Hey these SARS-1 antibodies 'almost' work"

Meanwhile there's literally a ton of antibodies out there that work well.

~~~
biophetik
One of the main reasons (most likely) is that these antibodies are already
purified and in stock in the laboratories. So I'd be relatively easy to start
researching the binding sites to SARS-COV-2. And since there is a relationship
between the 2 viruses you can get useful information even if it's not perfect.

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godzulu
Very interesting and hopeful. There is a documentary on Netflix and one of the
features docs may have another solution.

[https://sfist.com/2020/04/03/san-francisco-doctor-
featured-i...](https://sfist.com/2020/04/03/san-francisco-doctor-featured-in-
netflix-series-says-covid-19-treatment-could-be-ready-by-september/)

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pazimzadeh
Having an antibody bind the virus is good, but not enough. The antibody needs
to end up activating the immune system. Sometimes antibodies binding to the
virus can sometimes enhance the infection:

Potential Mechanims of Age Related Severity Of COVID-19 Infection:
Implications for Development of Vaccines, Convalescent Serum, and Antibody
Therapies
[https://www.researchgate.net/publication/340005309_Potential...](https://www.researchgate.net/publication/340005309_Potential_Mechanisms_of_Age_Related_Severity_of_COVID-19_Infection_Implications_for_Vaccine_Development_and_Convalescent_Serum_Therapy)

The back fo the antibody (Fc region) to COVID needs to be conjugated with an
activating factor.

~~~
christkv
From my understanding when an antibody attaches to a virus it causes a signal
for T-cells to eat the and destroy the virus. So the antibody would be
effective in getting the body to destroy any virus found. However I don't
think it would create any sort of immune memory which is what a vaccine or
recovering from the illness by yourself would do.

That said it would be fantastic in that it could provide some immunity
protection for a while why the antibodies are active in your body allowing
health care workers to be safer. Might also be very helpful in creating
firewalls in institutions like old folks homes or hospitals.

~~~
dmix
Are there some examples of antibodies like this being employed successfully
like that?

I find it fascinating how the body is able to adapt to new entrants and the
immune system figures out how to uniquely bind to the virus - but seemingly
based on the article only when it changes into an active infection mode and
exposes a certain part. Potentially ignoring it unless it’s an active threat
to the body.

~~~
AstralStorm
Yes, there have been some trials in avian flu at least, and a few attempts in
original SARS and MERS, with success.

The problem here is the mediocre quality of evidence. Mostly limited sizes,
but also lacking randomization.

Also rabies, tetanus and hepatitis B and C sera are available. Those have high
quality evidence for working.

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mrfusion
I never understood how animals without an adaptive immune system fight off
stuff like this. Like spiders for example.

~~~
im3w1l
It may simply be the normal predator-prey dynamic. Even if the predator is
infinitely more powerful than the prey it's not in their interest to wipe the
prey out. They want to leave enough prey for tomorrow. And if there are
defector predators that try to gain an edge by eating more than is
sustainable, other predators will try to stop them from doing so.

Now, before you object: it's not always perfectly balanced like this.
Sometimes the prey does go extinct.

~~~
sfj
> And if there are defector predators that try to gain an edge by eating more
> than is sustainable, other predators will try to stop them from doing so.

You're talking about a virus, you know... an inert molecule.

~~~
sweetdreamerit
An inert molecule that kills all its prey will not survive. The natural
selection will favor those molecules that are able to spread without
extinguishing all their guests.

~~~
blondin
oh wow, natural selection applies to non-living things?

~~~
asveikau
My background is nothing to do with biology, but it has struck me for years
that natural selection is just a broad statement about probabilities that can
be applied almost everywhere.

It is something like: if something has high odds to exist, given enough time
to possibly exist, it will exist.

So an inert protein coming into existence? Sure. Better odds to be replicated?
Then it'll happen. We ascribe agency or will to survive. Those probably help
the odds in a lot of cases. But the concept is broader than that.

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nojvek
We’ve had many viral outbreaks. SARS, MERS, Zika, Swine flu, HIV etc. some of
them have been with us for decades. Why don’t we have vaccines for all of them
yet?

Also how likely is that COVID-19 will mutate like influenza and become a
seasonal deadly killer ?

~~~
biophetik
Short answer. Money. You might like this podcast episode from planet money
[https://www.npr.org/2020/03/06/812943907/episode-977-wheres-...](https://www.npr.org/2020/03/06/812943907/episode-977-wheres-
the-vaccine).

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gniv
I wonder if this is why the vaccine announced from Pittsburgh [1] is
effective. Sounds like they adapted a SARS vaccine candidate.

[1] [https://www.upmc.com/media/news/040220-falo-gambotto-sars-
co...](https://www.upmc.com/media/news/040220-falo-gambotto-sars-cov2-vaccine)

------
heurifk
How does one isolate a specific antibody from the blood? Presumably there are
thousands (millions?) of different ones in there for all kinds of pathogens.

~~~
hcknwscommenter
Typically, you first test the blood to see if there are any antibodies in that
blood of interest. E.g., collect blood sample, harvest serum from blood by
coagulation and centrifugation, apply serum to surface coated with COVID
protein(s), wash away unbound material, detect whether antibodies to serum
have bound to surface coated with COVID proteins. If yes, then this is a blood
sample of interest. You could also test for neutralizing antibodies in
parallel/before/after/instead in a viral replication assay. Once you have
identified the blood as containing what you want, you then harvest more and
collect mature B cells. Mature B cells each produce one antibody. You isolate
the B cells by limiting dilution and/or immortalize them by fusion with a
special type of cell to make a hybridoma to isolate clonal populations of
single cells that are maintainable. Then you test each clonal population for
whether it produces the antibody of interest, isolate the nucleic acid that
encodes that antibody and put it into a cell type suitable for manufacturing.
There are other ways to do it, but the above is fairly standard. It is
laborious and easy to mess up and takes time (1 to 2 months) to do correctly.
Any step can go wrong and require starting over.

~~~
nojvek
Here’s a noob question. The coronavirus is made out of a whole bunch of
proteins. Have we fully mapped out all the protein structures and
corresponding DNA code?

The antigen is also a protein, I assume the DNA sequence for it is well known.
Right?

How far are we in terms of tech to print custom proteins from arbitrary DNA
sequences?

Is understanding protein folding and protein to protein interaction the holy
grail of making massive improvements in molecular biology? What are the big
unsolved problems?

Like if we know the virus’s DNA and it’s 3D protein architecture, we can solve
for antigen proteins in a computer that outputs possible DNA sequences and we
can manufacture them the next day in a protein printer. How far away are we to
that future?

~~~
biophetik
Protein folding is part of it. The other is finding which parts are antigenic
to the immune cells. Epitope mapping is a common method to screen small bits
of the proteins to see if any are hits for immune cells to recognize and kill.
There are algorithms that can take the RNA/DNA, predict proteins, and then
guess a percentage of those that may be important. But you still need to
synthesize those in mass quantities and start testing each. Once you have
candidates you then test them in mouse models (typically) to see if they
actually provide an immune response. If interested check out the iedb.
[https://www.iedb.org/](https://www.iedb.org/)

