Disclaimer: I know essentially nothing about US legislation, scientific ethical frameworks, etc. as I am not American. I just read the paper and have some background in genetics.
tl;dr: No, this is classic gain-of-function research as far as I can tell
From the paper, I can see two vaguely plausible arguments for why this isn’t gain-of-function research:
SARS-CoV is already (obviously) already capable of infecting human cells. Using SARS-CoV as a vector to test other spike proteins’ ability to infect humans doesn’t increase the number of hosts
Prior to the chimeric testing referred to, it seem like the authors did not expect the altered spike protein used (SHC014) was likely to successfully infect human cells; host-range regions were different from SARS-CoV, and it was unable to enter human cells when in a pseudovirus (which, as I understand it, are not fully replication-competent, making an outbreak unlikely)
However, neither of these arguments really holds water in my opinion. The first seems the strongest—my main concern is that introducing a different spike protein could plausibly increase transmissibility or pathogenicity, but I don’t know enough about that topic specifically to confidently evaluate that claim. If anybody does know I’d be interested to hear (for instance, do any SARS-CoV-2 variants have spike mutations?).
As to the second point; if you didn’t think it was plausible that SHC014-MA15 (the chimeric virus) would be capable of infecting human cells… why did you do the test in the first place?
Disclaimer: I know essentially nothing about US legislation, scientific ethical frameworks, etc. as I am not American. I just read the paper and have some background in genetics.
tl;dr: No, this is classic gain-of-function research as far as I can tell
From the paper, I can see two vaguely plausible arguments for why this isn’t gain-of-function research:
SARS-CoV is already (obviously) already capable of infecting human cells. Using SARS-CoV as a vector to test other spike proteins’ ability to infect humans doesn’t increase the number of hosts
Prior to the chimeric testing referred to, it seem like the authors did not expect the altered spike protein used (SHC014) was likely to successfully infect human cells; host-range regions were different from SARS-CoV, and it was unable to enter human cells when in a pseudovirus (which, as I understand it, are not fully replication-competent, making an outbreak unlikely)
However, neither of these arguments really holds water in my opinion. The first seems the strongest—my main concern is that introducing a different spike protein could plausibly increase transmissibility or pathogenicity, but I don’t know enough about that topic specifically to confidently evaluate that claim. If anybody does know I’d be interested to hear (for instance, do any SARS-CoV-2 variants have spike mutations?).
As to the second point; if you didn’t think it was plausible that SHC014-MA15 (the chimeric virus) would be capable of infecting human cells… why did you do the test in the first place?