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Comment by kmlevitt | Hacker News Reader

>”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.

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That go me too, but to be honest the title says it like it really is.

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

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

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

https://www.jsonline.com/story/news/2020/04/03/promising-use...

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.

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.

From the post:

>Labs at Scripps Research and throughout the world are currently seeking antibodies, via blood donations, from people who have recovered from COVID-19 for further studies along these lines.

Labs definitely are. People are working on basically every avenue you can imagine - this is a true global emergency and it's been stunning to see how strong the response has been from the scientific sector. Just about everyone that provides my reagents are all on backorder, but they're still working to make things available for covid work / making it easier etc, even with the immense demand

From the actual paper [0]:

Antibodies to this influenza HA trimeric interface epitope [that we studied before SARS-nCov-2 came along] do not exhibit in vitro neutralization activity but can confer in vivo protection. Similarly, antibodies to another conserved epitope that partially overlaps with the influenza HA trimeric interface also are non-neutralizing in vitro, but protective in vivo (26). Examples of antibodies that do not have in vitro neutralization activity but confer in vivo protection, have also been reported for influenza virus (27), herpesvirus (28), cytomegalovirus (29), alphavirus (30), and dengue virus (31). Therefore, although CR3022 does not neutralize SARS-CoV-2 in vitro, it is possible that this epitope can confer in vivo protection.

So the lack of in vitro neutralisation isn't a showstopper.

Still, that bit reads like reaching to me. We shouldn't expect this antibody to be that useful, although we can hope.

Moreover, i suspect we shouldn't think about manufactured antibodies as a treatment for COVID-19 at all, as i doubt we have the manufacturing capacity for biologicals to use them against a pandemic on this scale.

Rather, i think this points towards this part of the virus being a good target for vaccines. If you can make a nice little edited version of that epitope (the SARS-nCov-2 version), you might be able to use it to make a vaccine which raise neutralising antibodies.

[0] https://science.sciencemag.org/content/early/2020/04/02/scie...

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