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:
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 &
) 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.
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)
), 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).
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)
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)
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:
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)
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)
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)
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)