Our complete mapping of mutations to #SARSCoV2 RBD that reduce binding by convalescent human plasma is out in @cellhostmicrobe (cell.com/cell-host-micr…). Right now E484K getting lot of attention, but I want to emphasize what our results suggest to keep eyes on in *future* (1/n)
To recap, we measured how all mutations to RBD reduce binding by antibodies in convalescent plasma. Lots of person-to-person variation in effects of mutations, but mutations at E484 have biggest effect. My old summary from early Jan: (2/n)
That summary was written just as E484K-containing 501Y.V2 (B.1.351) & 501Y.V3 (P.1) lineages were being reported & focused on E484 as most important site of mutations. Since then, many labs have characterized these lineages to confirm E484K is major antigenic change. (3/n)
But our approach doesn't involve reactively characterizing mutations after they are observed in new lineages: rather, it prospectively maps effects of all mutations so we can know what to watch for next. So what to watch for? (4/n)
Well, E484 mutations are single worst change, & are already with us. But our maps show that next most important epitope for polyclonal convalescent antibodies is 443-450 loop in RBD (which peripherally includes sites like 452 & 494; see paper & ). (5/n)
Indeed, for minority of people, mutations in 443-450 loop (eg, at G446 as below ) already have bigger effect than E484K. And if E484 epitope is ablated as E484K spreads, I'd expect 443-450 loop to take on growing importance for remaining immunity. (6/n)
More generally, our maps measure effects of all mutations, so hope people refer back to them as new mutations are observed.

Finally, all of above results come from great efforts of @AllieGreaney, Andrea Loes, @khdcrawford, @tylernstarr, Keara Malone, @HelenChuMD. (7/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

25 Jan
Our study mapping #SARSCoV2 mutations that escape key therapeutic monoclonal antibodies is out in @ScienceMagazine. The study also shows that some of these escape mutations arise in a persistently infected patient treated with REGN-CoV-2: science.sciencemag.org/content/early/… (1/n)
I previously summarized the pre-print (), so in this thread I'll just update on new insights since we posted the pre-print in late November. (2/n)
In the study, we mapped all mutations to #SARSCoV2 RBD that escape binding by recombinant forms of antibodies in REGN-CoV2 cocktail (Regeneron) and LY-CoV016 antibody (Eli Lilly). These maps are useful because some of these mutations are appearing in new viral lineages (3/n).
Read 10 tweets
13 Jan
In this short thread, I am going to plot some experimental data in a way that provides perspective on concerns that #SARSCoV2 mutation E484K will completely abolish immunity. (Thanks @profshanecrotty @apoorva_nyc for inspiring this post.) (1/n)
Last week, we posted a study describing how some #SARSCoV2 mutations, especially at site E484, reduce binding & neutralization (). This study (& similar ones by other) have drawn a lot of interest since E484K is in B.1.351 viral lineage. (2/n)
However, E484 mutations *reduced* neutralization, they did not ablate it. The plot below shows how E484 reduces neutralization titers for 16 sera. The dashed orange line shows titers against unmutated virus (measured by Pfizer) after 1 dose of BNTB162 vaccine. (3/n)
Read 11 tweets
5 Jan
Here's plot of how mutating RBD sites affects average serum binding (y-axis) vs frequency of mutations (x-axis). E484K in S African lineage most worrying. But others affect some serum to various degrees & no such thing as "average" human when it comes to serum specificity (13/n) Image
Importantly, we only looked at RBD muts, since majority of neut activity of most sera from RBD antibodies (2nd tweet of thread). But NTD muts also important; see @10queues @mccarthy_kr @GuptaR_lab @e_andreano @McLellan_Lab: biorxiv.org/content/10.110…, medrxiv.org/content/10.110… (14/n)
This relative role of RBD & NTD mutations consistent w historical evolution of common-cold CoV-229E, where mutations concentrated in receptor-binding loops of RBD, but also in parts of NTD. Here is plot of mutational variability in CoV-229E spike: (15/n)
Read 16 tweets
5 Jan
We mapped how all mutations to #SARSCoV2 receptor-binding domain (RBD) affect recognition by convalescent polyclonal human sera (biorxiv.org/content/10.110…).

Among implications: E484K (South African lineage) worrying for immune escape; RBD mutations in UK lineage less so (1/n).
We first determined where in #SARSCoV2 mutations most affect viral neutralization. @veeslerlab had reported RBD-binding antibodies responsible for most neut activity of human sera: sciencedirect.com/science/articl…. We validated w sera from @HelenChuMD's HAARVI cohort (below) (2/n)
Since RBD is main antigenic region (although NTD also important, see below), @AllieGreaney applied method she & @tylernstarr developed for monoclonal antibodies (sciencedirect.com/science/articl…) to map how all mutations to RBD affect binding by *polyclonal* human sera (3/n)
Read 28 tweets
18 Dec 20
In new work, we show a human coronavirus evolves to escape neutralization by antibody immunity (biorxiv.org/content/10.110…). Specifically, we studied the historical evolution of the common-cold CoV-229E to learn how #SARSCoV2 might evolve & if we might need to update vaccines. (1/n)
We first built a phylogenetic tree of CoV-229E evolution from 1984 to the present, and experimentally reconstructed the spike from viruses at 8 year intervals (1984, 1992, etc; see large black strain names in tree below). (2/n) Image
Next we tested how well human sera collected shortly after 1984 neutralized each viral spike. Below is serum from 26 yr old collected in 1985: it neutralizes 1984 virus well, but 10-fold less activity against 1992 virus & no activity against viruses after 2008. (3/n) Image
Read 17 tweets
2 Dec 20
After posting our pre-print mapping #SARS_CoV_2 mutations that escape Regeneron antibodies, been getting questions about implications for therapies/vaccines. I'd like to contextualize results. Summary is don't be alarmed, but pay attention to viral evolution. Long version: (1/n)
Antibody treatments consist of a single antibody (or in some cases a cocktail of a few) that bind viral spike. Since an antibody binds to one small patch of virus, typically a single mutation is sufficient to escape binding by an antibody. (2/n)
We know from other viruses this can happen. One of the best examples is Regeneron's trial of an antibody to treat RSV in infants (academic.oup.com/cid/advance-ar…). They ran an entire large / expensive clinical trial that failed. Retrospectively, the reason was obvious... (3/n)
Read 21 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

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

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!