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Slack / Private Message Drop, p.336 [SLACK_000550] · slack_pm:msg:03539

Date: 2020-12-21 15:57
Type: chat message · slack
recipient: Kristian G. Andersen, Edward C. Holmes, Andrew Rambaut
speaker: Robert F. Garry

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From Sun: "In our previous study, we generated a mouse-adapted strain of SARS-CoV-2 (MASCp6) by 6 serial passages of a SARS-CoV-2 in the lung of *aged* BALB/c mice, which caused moderate lung damage and no fatality in mice. Herein, we further serially passaged for additional 30 times to generate a more virulent SARS-CoV-2, and the resulting virus at passage 36 ( named as MASCp36) was used for stock preparation and titration." And a little deeper dive into the supplement reveals that N501Y came up early - by 6 passages [and it wasn't pathogenic] the other 2 muts took more passages [and tjhose mutations - probably Q493K actually made the virus pathogenic for mice. . Aged mice are definitely immunosuppressed. So, evidence for the immunocompromised theory.

In context

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2020-12-21 14:42 Robert F. Garry open

guess not - color blind
2020-12-21 14:57 Andrew Rambaut open

My feeling is the Welsh cluster isn't growing at the same rate. It is at least as old but hasn't taken over or spread toother places. Also may have been amplified by some hospital outbreaks.
2020-12-21 14:59 Kristian G. Andersen open

Makes sense.
2020-12-21 15:14 Andrew Rambaut open

Just found a genome from mid July that has N501Y and the ORF8 stop Possibly part of the precursor lineage.
2020-12-21 15:57 Robert F. Garry

From Sun: "In our previous study, we generated a mouse-adapted strain of SARS-CoV-2 (MASCp6) by 6 serial passages of a SARS-CoV-2 in the lung of *aged* BALB/c mice, which caused moderate lung damage and no fatality in mice. Herein, we further serially passaged for additional 30 times to generate a more virulent SARS-CoV-2, and the resulting virus at passage 36 ( named as MASCp36) was used for stock preparation and titration." And a little deeper dive into the supplement reveals that N501Y came up early - by 6 passages [and it wasn't pathogenic] the other 2 muts took more passages [and tjhose mutations - probably Q493K actually made the virus pathogenic for mice. . Aged mice are definitely immunosuppressed. So, evidence for the immunocompromised theory.
2020-12-21 16:07 Edward C. Holmes open

https://www.bbc.com/news/world-asia-china-55364445
2020-12-21 16:13 Andrew Rambaut open

We should offer to go do it.
2020-12-21 16:13 Kristian G. Andersen open

YES - we can collect our fat checks at the same time!
2020-12-21 16:14 Kristian G. Andersen open

One question I'd ask - "Since you faked RaTG13, why haven't you faked a closely related ancestral strain from a random intermediate host?"

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