CiDRE+ M2c macrophages hijacked by SARS-CoV-2 cause COVID-19 severity

Infection of the lungs with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via the angiotensin I converting enzyme 2 (ACE2) receptor induces a type of systemic inflammation known as a cytokine storm. However, the precise mechanisms involved in severe coronavirus disease 2019 (COVID-19) pneumonia are unknown. Here, we show that interleukin-10 (IL-10) changed normal alveolar macrophages into ACE2-expressing M2c-type macrophages that functioned as spreading vectors for SARS-CoV-2 infection. The depletion of alveolar macrophages and blockade of IL-10 attenuated SARS-CoV-2 pathogenicity. Furthermore, genome-wide association and quantitative trait locus analyses identified novel mRNA transcripts in human patients, COVID-19 infectivity enhancing dual receptor (CiDRE), which has unique synergistic effects within the IL-10-ACE2 system in M2c-type macrophages. Our results demonstrate that alveolar macrophages stimulated by IL-10 are key players in severe COVID-19. Collectively, CiDRE expression levels are potential risk factors that predict COVID-19 severity, and CiDRE inhibitors might be useful as COVID-19 therapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=195 HEIGHT=200 SRC="FIGDIR/small/510331v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1e96c82org.highwire.dtl.DTLVardef@1d2dc32org.highwire.dtl.DTLVardef@7689d1org.highwire.dtl.DTLVardef@520d17_HPS_FORMAT_FIGEXP M_FIG C_FIG

InterClone: Store, Search and Cluster Adaptive Immune Receptor Repertoires

B and T cell receptor repertoire data has the potential to fundamentally change the way we diagnose and treat a wide range of diseases. However, there are few resources for storing or analyzing repertoire data. InterClone provides tools for storing, searching, and clustering repertoire datasets. Efficiency is achieved by encoding the complementarity-determining regions of sequences as mmseqs2 databases. Single chain search or cluster results can be merged into paired (alpha-beta or heavy-light) results for analysis of single-cell sequencing data. We illustrate the use of InterClone with two recently reported examples: 1) searching for SARS-CoV-2 infection-enhancing antibodies in bulk COVID-19 and healthy donor repertoires; 2) identification of SARS-CoV-2 specific TCRs by clustering paired and bulk sequences from COVID-19, BNT162b2 vaccinated and healthy unvaccinated donors. The core functions of InterClone have been implemented as a web server and integrated database (https://sysimm.org/interclone). All source code is available upon request.

Landscape of infection enhancing antibodies in COVID-19 and healthy donors

To assess the frequency of SARS-CoV-2 infection enhancing antibodies in the general population, we searched over 64 million heavy chain antibody sequences from healthy and COVID-19 patient repertoires for sequences similar to 11 previously reported enhancing antibodies. Although the distribution of sequence identities was similar in COVID-19 and healthy repertoires, the COVID-19 hits were significantly more clonally expanded than healthy hits. Furthermore, among the tested hits, 17 out of 94 from COVID-19, compared with 2 out of 96 from healthy, bound to the enhancing epitope. A total of 6 of the 19 epitope-binding antibodies enhanced ACE2 receptor binding to the spike protein. Together, this study revealed that enhancing antibodies are far more frequent in COVID-19 patients than in healthy donors, but a reservoir of potential enhancing antibodies exists in healthy donors that could potentially mature to actual enhancing antibodies upon infection.

Engineered ACE2 counteracts vaccine-evading SARS-CoV-2 Omicron variant

The novel SARS-CoV-2 variant, Omicron (B.1.1.529) contains an unusually high number of mutations (>30) in the spike protein, raising concerns of escape from vaccines, convalescent sera and therapeutic drugs. Here we analyze the alteration of neutralizing titer with Omicron pseudovirus. Sera obtained 3 months after double BNT162b2 vaccination exhibit approximately 18-fold lower neutralization titers against Omicron than parental virus. Convalescent sera from Alpha and Delta patients allow similar levels of breakthrough by Omicron. Domain-wise analysis using chimeric spike revealed that this efficient evasion was primarily achieved by mutations clustered in the receptor-binding domain, but that multiple mutations in the N-terminal domain contributed as well. Omicron escapes a therapeutic cocktail of imdevimab and casirivimab, whereas sotrovimab, which targets a conserved region to avoid viral mutation, remains effective. The ACE2 decoy is another virus-neutralizing drug modality that is free, at least in theory, from complete escape. Deep mutational analysis demonstrated that, indeed, engineered ACE2 prevented escape for each single-residue mutation in the receptor-binding domain, similar to immunized sera. Engineered ACE2 neutralized Omicron comparable to Wuhan and also showed a therapeutic effect against Omicron infection in hamsters and human ACE2 transgenic mice. Like previous SARS-CoV-2 variants, some sarbecoviruses showed high sensitivity against engineered ACE2, confirming the therapeutic value against diverse variants, including those that are yet to emerge. One Sentence SummaryOmicron, carrying [~]30 mutations in the spike, exhibits effective immune evasion but remains highly susceptible to blockade by engineered ACE2.

The SARS-CoV-2 Delta variant is poised to acquire complete resistance to wild-type spike vaccines

mRNA-based vaccines provide effective protection against most common SARS-CoV-2 variants. However, identifying likely breakthrough variants is critical for future vaccine development. Here, we found that the Delta variant completely escaped from anti-N-terminal domain (NTD) neutralizing antibodies, while increasing responsiveness to anti-NTD infectivity-enhancing antibodies. Although Pfizer-BioNTech BNT162b2-immune sera neutralized the Delta variant, when four common mutations were introduced into the receptor binding domain (RBD) of the Delta variant (Delta 4+), some BNT162b2-immune sera lost neutralizing activity and enhanced the infectivity. Unique mutations in the Delta NTD were involved in the enhanced infectivity by the BNT162b2-immune sera. Sera of mice immunized by Delta spike, but not wild-type spike, consistently neutralized the Delta 4+ variant without enhancing infectivity. Given the fact that a Delta variant with three similar RBD mutations has already emerged according to the GISAID database, it is necessary to develop vaccines that protect against such complete breakthrough variants.

An infectivity-enhancing site on the SARS-CoV-2 spike protein is targeted by COVID-19 patient antibodies

SARS-CoV-2 infection causes severe symptoms in a subset of patients, suggesting the presence of certain unknown risk factors. Although antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 spike have been shown prevent SARS-CoV-2 infection, the effects of antibodies against other spike protein domains are largely unknown. Here, we screened a series of anti-spike monoclonal antibodies from COVID-19 patients, and found that some of antibodies against the N-terminal domain (NTD) dramatically enhanced the binding capacity of the spike protein to ACE2, and thus increased SARS-CoV2 infectivity. Surprisingly, mutational analysis revealed that all the infectivity-enhancing antibodies recognized a specific site on the surface of the NTD. The antibodies against this infectivity-enhancing site were detected in all samples of hospitalized COVID-19 patients in the study. However, the ratio of infectivity-enhancing antibodies to neutralizing antibodies differed among patients. Furthermore, the antibodies against the infectivity-enhancing site were detected in 3 out of 48 uninfected donors, albeit at low levels. These findings suggest that the production of antibodies against SARS-CoV-2 infectivity-enhancing site could be considered as a possible exacerbating factors for COVID-19 and that a spike protein lacking such antibody epitopes may be required for safe vaccine development, especially for individuals with pre-existing enhancing antibodies.