Bloom Lab Profile picture
Jun 24, 2021 5 tweets 2 min read Read on X
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): (3/n)
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: (5/n)

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Bloom Lab

Bloom Lab Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @jbloom_lab

Nov 21
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
First, the updated escape calculator is at

As shown below, it is remarkable how much antigenicity of RBD has changed over last 4 yrs. jbloomlab.github.io/SARS2-RBD-esca…Image
Updated data for calculator from this paper by @yunlong_cao’s group (nature.com/articles/s4158…), described in this thread by first author @jianfcpku:
x.com/jianfcpku/stat…

Calculator show how much mutations at each RBD site escape binding by set of neutralizing antibodies
Read 13 tweets
Nov 16
@Nucleocapsoid @HNimanFC @mrmickme2 @0bFuSc8 @PeacockFlu @CVRHutchinson Good observations. See also this thread posted by @SCOTTeHENSLEY:

I have added a few notes to the bottom of that thread.

To recap here:bsky.app/profile/scotte…
@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…
Read 6 tweets
Oct 8
Below is brief analysis of HA mutations in two recent cases of H5N1 influenza in humans w contact w dairy cattle in California.

Summary is that while virus continues to evolve, nothing about HA mutations in these human cases is obviously alarming. Image
As background, CDC reported several recent cases of H5 influenza in California.

CDC and California DOH recently shared sequences of two of these cases via GISAID.
cdc.gov/media/releases…
California human cases share two HA mutations relative to "consensus" dairy cattle virus HA:

D95G & S336N in H3 numbering (D88G & S320N in H5 numbering; D014G & S336N in sequential numbering).

Both these mutations also in some dairy cattle HAs, so not unique to human cases. Image
Read 10 tweets
Sep 15
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.
Read 16 tweets
May 25
In new study led by @bdadonaite, we measure how all mutations to H5 influenza HA affect four molecular phenotypes relevant to pandemic risk:


Results can inform surveillance of ongoing evolution of H5N1. biorxiv.org/content/10.110…
Image
To measure how all HA mutations affect those phenotypes, we created pseudovirus libraries of HA from WHO clade 2.3.4.4b vaccine strain.

Pseudoviruses encode no genes other than HA, so can only do a single cycle of infection making them safe for biosafety-level-2. Image
First, we measured how all mutations affected HA-mediated cell entry, which is essential for viral fitness

See heatmap below, which is easily visualized interactively at

Some sites constrained (orange); others w many well tolerated mutations (white/blue) dms-vep.org/Flu_H5_America…
Image
Read 15 tweets
Apr 20
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) Image
Read 12 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(