Compared to the S protein of SARS-CoV-2 B.1, which circulated in the early phase of the pandemic, the S protein of the
A.30 variant contains 10 amino acid substitutions and five deletions (Fig.
1a and Supplementary information, Fig.
S1a). All deletions along with four substitutions are found in the N-terminal domain of the surface unit S1, which harbors an antigenic supersite that is targeted by most neutralizing antibodies not directed against the
receptor-binding domain (RBD) [
5].
In addition, three mutations are located inside the RBD, which binds to the cellular receptor ACE2 and constitutes the main target of neutralizing antibodies (Fig.
1a).
Two of these mutations, T478R and E484K, are
located close to the ACE2 binding site (Supplementary information, Fig.
S1a), and E484K is known to
reduce susceptibility to antibody-mediated neutralization. Finally, two mutations are located close to the S1/S2 cleavage site, and one mutation is found in the transmembrane unit S2, which facilitates fusion of the viral envelope with cellular membranes (Fig.
1a).
So from what I could discern from this, the new variant under the microscope here is a fledgling right now, at least in terms of global spread. This "A.30" variant is unlike the previous because of its huge umber of mutations and what those mutations make it capable of, most notably being its increased infectivity and the ability to no-sell antibodies.
In summary, A.30 exhibits a cell line preference not observed for other viral variants and efficiently evades neutralization by antibodies elicited by ChAdOx1 nCoV-19 or BNT162b2 vaccination.
SARS-CoV-2 entry into cell lines depends on S protein activation by the cellular proteases cathepsin L or TMPRSS2 [8], and activation by the latter is thought to support viral spread in the lung. Therefore, it is noteworthy that enhanced A.30 entry was observed for cell lines with cathepsin L (Vero, 293 T, Huh-7, A549 cells)—but not TMPRSS2 (Calu-3, Caco-2)-dependent entry [8].
That's weird, isn't it? I wonder what that means. Makes me recall what
@Otterly had been concerned about, the very thing
@Fanatical Pragmatist and others ITT had mentioned, too--that this mad push for mass vaccination could incite evolutionary changes in Covid's variants that would make it far more dangerous, if not deadlier, than before. Is this change in the A.30 variant due to the new environment created from the vaccine mandates?
Of course it wasn't just Kiwisthis was also a concern of many noted scientists who had published a peer reviewed study on the issue, as I recall. Might be in one of the PDFs in the OP for those interested.
Thus, one could speculate that A.30 might use cathepsin L with increased efficiency and slight (but not statistically significant) resistance of A.30 against the cathepsin L inhibitor MDL 28170 supports this possibility (
Supplemental information, Fig.
S1c).
Notably, robust entry into cell lines was combined with high resistance against antibodies induced upon ChAdOx1 nCoV-19 or BNT162b2 vaccination. Neutralization resistance exceeded that of the Beta (B.1.351) variant, which is markedly neutralization resistant in cell culture and, in comparison with the Alpha (B.1.1.7) variant, is less well inhibited by the ChAdOx1 nCoV-19 vaccine [
9].
So that's where the header comes from and the big concern here is that it's not just a sudden change in the variant which produced this result. There's signs even in certain previous "variants of concern" (VOC) that each new iteration of Covid was slowly starting to develop this WWE no-sell of antibodies. A.30 is the latest iteration to show how this mechanism has improved as the virus develops into newer strains.
At least, from what I can gather.