I am getting lots of questions if my pre-print about some #SARSCoV2 sequences that were removed from Sequence Read Archive tell us anything about lab accident versus natural zoonosis.
I posted summary of pre-print below, but did not directly address this point explicitly (1/n)
The answer is NO. The people using it to strongly support either argument are those that have become so emotionally invested in their opinion that they have lost the ability to analyze anything objectively outside of the framework of that argument. (2/n)
What the pre-print does imply is as follows:
First, there may be additional relevant data in obscure locations that aren't the places where we are accustomed to looking (e.g., on the Google Cloud, in table 1 of a paper on diagnostics, etc):
Second, in my opinion, anybody doing phylogenetics on early #SARSCoV2 sequences from China should spend as much time on metadata as algorithms. Sequences in databases may be non-representative. Sequences collected in Guangdong might be from infections from Wuhan. Etc. (4/n)
Third, preprint provides modestly more evidence for progenitor being in clade A (not market clade), & substantially more evidence it might have T at site 29095. However, current inferences are likely based on incomplete data. @sergeilkp says it best:
I’ve updated SARSCoV2 antibody-escape calculator w new deep mutational scanning data of @yunlong_cao @jianfcpku
My interpretation: antigenic evolution currently constrained by pleiotropic effects of mutations on RBD-ACE2 affinity, RBD up-down position & antibody neutralization
@Nucleocapsoid @HNimanFC @mrmickme2 @0bFuSc8 @PeacockFlu @CVRHutchinson @SCOTTeHENSLEY To add to thread linked above, human British Columbia H5 case has a HA sequence (GISAID EPI_ISL_19548836) that is ambiguous at *both* site Q226 and site E190 (H3 numbering)
Both these sites play an important role in sialic acid binding specificity
@Nucleocapsoid @HNimanFC @mrmickme2 @0bFuSc8 @PeacockFlu @CVRHutchinson @SCOTTeHENSLEY If you are searching literature, these sites are E190 and Q226 in H3 numbering, E186 and Q222 in mature H5 numbering, and E202 and Q238 in sequential H5 numbering (see: )dms-vep.org/Flu_H5_America…
Here is analysis of HA mutations in H5 influenza case in Missouri resident without known contact w animals or raw milk.
TLDR: there is one HA mutation that strongly affects antigenicity, and another that merits some further study.
As background, CDC recently released partial sequence of A/Missouri/121/2024, which is virus from person in Missouri who was infected with H5 influenza.
Here I am analyzing HA protein from this release, GISAID accession EPI_ISL_19413343cdc.gov/bird-flu/spotl…
Sequence covers all of HA except signal peptide, and residues 325-351 (sequential numbering) / 312-335 (H3 numbering). The missing residues encompass HA1-HA2 boundary, and any missed mutations there unlikely to affect antigenicity or receptor binding, but could affect stability.
In new study led by @bblarsen1 in collab w @veeslerlab @VUMC_Vaccines we map functional & antigenic landscape of Nipah virus receptor binding protein (RBP)
Results elucidate constraints on RBP function & provide insight re protein’s evolutionary potentialbiorxiv.org/content/10.110…
Nipah is bat virus that sporadically infects humans w high (~70%) fatality rate. Has been limited human transmission
Like other paramyxoviruses, Nipah uses two proteins to enter cells: RBP binds receptor & then triggers fusion (F) protein by process that is not fully understood
RBP forms tetramer in which 4 constituent monomers (which are all identical in sequence) adopt 3 distinct conformations
RBP binds to two receptors, EFNB2 & EFNB3
RBP’s affinity for EFNB2 is very high (~0.1 nM, over an order of magnitude higher than SARSCoV2’s affinity for ACE2)