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Most neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) target the receptor binding domain (RBD) of the spike (S) protein. Here, we characterize a panel of mAbs targeting the N-terminal domain (NTD) or other non-RBD epitopes of S. A subset of NTD mAbs inhibits SARS-CoV-2 entry at a post-attachment step and avidly binds the surface of infected cells. One neutralizing NTD mAb, SARS2-57, protects K18-hACE2 mice against SARS-CoV-2 infection in an Fc-dependent manner. Structural analysis demonstrates that SARS2-57 engages an antigenic supersite that is remodeled by deletions common to emerging variants. In neutralization escape studies with SARS2-57, this NTD site accumulates mutations, including a similar deletion, but the addition of an anti-RBD mAb prevents such escape. Thus, our study highlights a common strategy of immune evasion by SARS-CoV-2 variants and how targeting spatially distinct epitopes, including those in the NTD, may limit such escape., Competing Interests: Declaration of interests M.S.D. is a consultant for Inbios, Vir Biotechnology, Ocugen, Topspin Therapeutics, GlaxoSmithKline, Moderna, and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Vir Biotechnology, Emergent BioSolutions, and Moderna. Some of the mAbs described in this study have been licensed by Washington University to Bio X Cell. D.H.F. is a founder of Courier Therapeutics and has received funding support in a sponsored research agreement from Emergent BioSolutions. J.E.C. has served as a consultant for Eli Lilly and Luna Biologics, is a member of the Scientific Advisory Boards of CompuVax and Meissa Vaccines, and is the founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received sponsored research agreements from AstraZeneca and IDBiologics., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

MXRA8 is a receptor for chikungunya (CHIKV) and other arthritogenic alphaviruses with mammalian hosts. However, mammalian MXRA8 does not bind to alphaviruses that infect humans and have avian reservoirs. Here, we show that avian, but not mammalian, MXRA8 can act as a receptor for Sindbis, western equine encephalitis (WEEV), and related alphaviruses with avian reservoirs. Structural analysis of duck MXRA8 complexed with WEEV reveals an inverted binding mode compared with mammalian MXRA8 bound to CHIKV. Whereas both domains of mammalian MXRA8 bind CHIKV E1 and E2, only domain 1 of avian MXRA8 engages WEEV E1, and no appreciable contacts are made with WEEV E2. Using these results, we generated a chimeric avian-mammalian MXRA8 decoy-receptor that neutralizes infection of multiple alphaviruses from distinct antigenic groups in vitro and in vivo. Thus, different alphaviruses can bind MXRA8 encoded by different vertebrate classes with distinct engagement modes, which enables development of broad-spectrum inhibitors., Competing Interests: Declaration of interests M.S.D. is a consultant to or member of a Scientific Advisory Board for Inbios, Ocugen, Vir Biotechnology, Topspin Therapeutics, and Moderna. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Emergent BioSolutions, Moderna, Generate Biomedicines, Vir Biotechnology, and Immunome. D.H.F. is a founder of Courier Therapeutics and his laboratory has received unrelated funding support from Emergent BioSolutions and Mallinckrodt Pharmaceuticals. J.M.E. is an employee of Vir Biotechnology., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 has led to the development of a large number of vaccines, several of which are now approved for use in humans. Understanding vaccine-elicited antibody responses against emerging SARS-CoV-2 variants of concern (VOCs) in real time is key to inform public health policies. Serum neutralizing antibody titers are the current best correlate of protection from SARS-CoV-2 challenge in non-human primates and a key metric to understand immune evasion of VOCs. We report that vaccinated BALB/c mice do not recapitulate faithfully the breadth and potency of neutralizing antibody responses elicited by various vaccine platforms against VOCs, compared with non-human primates or humans, suggesting caution should be exercised when interpreting data obtained with this animal model., Competing Interests: Declaration of interests A.C.W., N.P.K., and D.V. are named as inventors on patent applications filed by the University of Washington based on the RBD-NP presented in this paper. N.P.K. is a co-founder, shareholder, paid consultant, and chair of the scientific advisory board of Icosavax, Inc., and the King lab has received an unrelated sponsored research agreement from Pfizer. M.S.D. is a consultant for Inbios, Vir Biotechnology, and Carnival Corporation, and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Vir Biotechnology, Kaleido, and Emergent BioSolutions and past support from Moderna not related to these studies. K.W., A.C., and D.K.E are employees of Moderna and hold stock/stock options in the company. D.H.F. has equity interest in HDT Bio., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Individuals with primary antibody deficiency (PAD) syndromes have poor humoral immune responses requiring immunoglobulin replacement therapy. We followed individuals with PAD after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination by evaluating their immunoglobulin replacement products and serum for anti-spike binding, Fcγ receptor (FcγR) binding, and neutralizing activities. The immunoglobulin replacement products tested have low anti-spike and receptor-binding domain (RBD) titers and neutralizing activity. In coronavirus disease 2019 (COVID-19)-naive individuals with PAD, anti-spike and RBD titers increase after mRNA vaccination but wane by 90 days. Those vaccinated after SARS-CoV-2 infection develop higher and more sustained responses comparable with healthy donors. Most vaccinated individuals with PAD have serum-neutralizing antibody titers above an estimated correlate of protection against ancestral SARS-CoV-2 and Delta virus but not against Omicron virus, although this is improved by boosting. Thus, some immunoglobulin replacement products likely have limited protective activity, and immunization and boosting of individuals with PAD with mRNA vaccines should confer at least short-term immunity against SARS-CoV-2 variants, including Omicron., Competing Interests: Declaration of interests M.S.D. is a consultant for Inbios, Vir Biotechnology, Senda Biosciences, and Carnival Corporation and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Moderna, Vir Biotechnology, Immunome, and Emergent BioSolutions. O.Z. and family own Moderna stock. G.A. is a founder and equity holder for Seromyx Systems Inc. and an equity holder for Leyden Labs. The Ellebedy laboratory received unrelated funding support from Emergent BioSolutions and AbbVie. A.H.E. is a consultant for Mubadala Investment Company and the founder of ImmuneBio Consulting. J.S.T. is a consultant for Gerson Lehrman Group. J.S.T. and A.H.E. are recipients of a licensing agreement with Abbvie that is unrelated to this manuscript., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019, viral variants with greater transmissibility or immune-evasion properties have arisen, which could jeopardize recently deployed vaccine- and antibody-based countermeasures., Methods: Here, we evaluated in mice and hamsters the efficacy of a pre-clinical version of the Moderna mRNA vaccine (mRNA-1273) and the Johnson & Johnson recombinant adenoviral-vectored vaccine (Ad26.COV2.S) against the B.1.621 (Mu) variant of SARS-CoV-2, which contains spike mutations T95I, Y144S, Y145N, R346K, E484K, N501Y, D614G, P681H, and D950N., Findings: Immunization of 129S2 and K18-human ACE2 transgenic mice with the mRNA-1273 vaccine protected against weight loss, lung infection, and lung pathology after challenge with the B.1.621 or WA1/2020 N501Y/D614G SARS-CoV-2 strain. Similarly, immunization of 129S2 mice and Syrian hamsters with a high dose of Ad26.COV2.S reduced lung infection after B.1.621 virus challenge., Conclusions: Thus, immunity induced by the mRNA-1273 or Ad26.COV2.S vaccine can protect against the B.1.621 variant of SARS-CoV-2 in multiple animal models., Funding: This study was supported by the NIH (R01 AI157155 and U01 AI151810), NIAID Centers of Excellence for Influenza Research and Response [CEIRR] contracts 75N93021C00014 and 75N93021C00016, and the Collaborative Influenza Vaccine Innovation Centers [CIVIC] contract 75N93019C00051. It was also supported, in part, by the National Institutes of Allergy and Infectious Diseases Center for Research on Influenza Pathogenesis (HHSN272201400008C) and the Japan Program for Infectious Diseases Research and Infrastructure (JP21wm0125002) from the Japan Agency for Medical Research and Development (AMED)., Competing Interests: Declaration of interests The A.C.M.B. laboratory has received unrelated funding support in sponsored research agreements from AI Therapeutics, GreenLight Biosciences, Inc., and Nano Targeting & Therapy Biopharma, Inc. The A.C.M.B. laboratory has received funding support from AbbVie, Inc., for the commercial development of SARS-CoV-2 mAbs. M.S.D. is a consultant for Inbios, Vir Biotechnology, Senda Biosciences, and Carnival Corporation and is on the Scientific Advisory Boards of Moderna and Immunome. The M.S.D. laboratory has received unrelated funding support in sponsored research agreements from Vir Biotechnology, Kaleido, and Emergent BioSolutions and past support from Moderna not related to these studies. S.M.E. and D.K.E. are employees of and shareholders in Moderna, Inc., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Human monoclonal antibody (mAb) treatments are promising for COVID-19 prevention or therapy. The pre-exposure prophylactic efficacy of neutralizing antibodies that are engineered with mutations to extend their persistence in human serum and the neutralizing antibody titer in serum required for protection against SARS-CoV-2 infection remain poorly characterized., Methods: The Fc region of two neutralizing mAbs (COV2-2130 and COV2-2381) targeting non-overlapping epitopes on the receptor binding domain of SARS-CoV-2 spike protein was engineered to extend their persistence in humans and reduce interactions with Fc gamma receptors. We assessed protection by individual antibodies or a combination of the two antibodies (designated ADM03820) given prophylactically by an intravenous or intramuscular route in a non-human primate (NHP) model of SARS-CoV-2 infection., Findings: Passive transfer of individual mAbs or ADM03820 conferred virological protection in the NHP respiratory tract in a dose-dependent manner, and ADM03820 potently neutralized SARS-CoV-2 variants of concern in vitro . We defined a protective serum-neutralizing antibody titer and concentration in NHPs for passively transferred human antibodies that acted by direct viral neutralization., Conclusions: In summary, we demonstrate that neutralizing antibodies with extended half-life and lacking Fc-mediated effector functions are efficient for pre-exposure prophylaxis of SARS-CoV-2 infection in NHPs. These results support clinical development of ADM03820 for COVID-19 prevention., Funding: This research was supported by a contract from the JPEO-CBRND (W911QY-20-9-003, 20-05); the Joint Sciences and Technology Office and Joint Program Executive Office (MCDC-16-01-002 JSTO, JPEO); a DARPA grant (HR0011-18-2-0001); an NIH grant (R01 AI157155); and the 2019 Future Insight Prize from Merck KGaA., Competing Interests: R.R.C., R.V.H., D.M.S., M.H., B.H., L.C., G.H.N., M.T.T., and K.H. are employees of Ology Bioservices. C.G.E. and N.M.D. are employees of the Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense for the US Department of Defense (JPEO-CBRND). S.A.H. is an employee of Logistics Management Institute (LMI), performing technical contract support for JPEO-CBRND. J.E.C. has served as a consultant for Luna Innovations, is a member of the scientific advisory board of Meissa Vaccines, and is founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received sponsored research agreements from Takeda, IDBiologics, and AstraZeneca. Vanderbilt University has applied for patents related to antibodies studied in this paper. M.S.D. is a consultant for InBios, Vir Biotechnology, Senda Biosciences, and Carnival Corporation and is on the scientific advisory boards of Moderna and Immunome. The laboratory of M.S.D. has received funding support in sponsored research agreements from Moderna, Vir Biotechnology, Kaleido, and Emergent BioSolutions., (© 2022 Elsevier Inc.)

The COVID-19 pandemic revealed an urgent need for rapid profiling of neutralizing antibody responses and development of antibody therapeutics. The current Food and Drug Administration-approved serological tests do not measure antibody-mediated viral neutralization, and there is a need for standardized quantitative neutralization assays. We report a high-throughput two-step profiling approach for identifying neutralizing convalescent plasma. Screening and downselection for serum antibody binding to the receptor-binding domain are followed by quantitative neutralization testing using a chimeric vesicular stomatitis virus expressing spike protein of SARS-CoV-2 in a real-time cell analysis assay. This approach enables a predictive screening process for identifying plasma units that neutralize SARS-CoV-2. To calibrate antibody neutralizing activity in serum from convalescent plasma donors, we introduce a neutralizing antibody standard reagent composed of two human antibodies that neutralize SARS-CoV strains, including SARS-CoV-2 variants of concern. Our results provide a framework for establishing a standardized assessment of antibody-based interventions against COVID-19., Competing Interests: I.T. reports grants from NIH/NIAID, during the conduct of the study, and has served as a consultant for Nashville Biosciences and Horizon Therapeutics. J. D. C., L.J.S., and M.R.D. report grants from NIH/NCATS, during the conduct of the study. T.W.R. reports grants from NIH/NCATS, during the conduct of the study; personal fees from Cumberland Pharmaceuticals, Inc, personal fees from Sanofi Pharma, and personal fees from Cytovale, outside the submitted work. T.G.S. reports grants from NIH, during the conduct of the study. W.H.S. reports grants from NCATS of the NIH, during the conduct of the study. M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, and Carnival Corporation and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received funding support in sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions. J.E.C. has served as a consultant for Luna Biologics, is a member of the Scientific Advisory Board of Meissa Vaccines and is Founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received sponsored research agreements from Takeda Vaccines, IDBiologics, and AstraZeneca and grants from NIH, and DARPA during the conduct of the study. Vanderbilt University has applied for patents related to antibodies described in this paper. All other authors declare no competing interests., (© 2021 The Authors.)

Background: Although vaccines effectively prevent coronavirus disease 2019 (COVID-19) in healthy individuals, they appear to be less immunogenic in individuals with chronic inflammatory disease (CID) or receiving chronic immunosuppression therapy., Methods: Here we assessed a cohort of 77 individuals with CID treated as monotherapy with chronic immunosuppressive drugs for antibody responses in serum against historical and variant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses after immunization with the BNT162b2 mRNA vaccine., Findings: Longitudinal analysis showed the greatest reductions in neutralizing antibodies and Fc effector function capacity in individuals treated with tumor necrosis factor alpha (TNF-α) inhibitors (TNFi), and this pattern appeared to be worse against the B.1.617.2 delta virus. Within 5 months of vaccination, serum neutralizing titers of all TNFi-treated individuals tested fell below the presumed threshold correlate for antibody-mediated protection. However, TNFi-treated individuals receiving a third mRNA vaccine dose boosted their serum neutralizing antibody titers by more than 16-fold., Conclusions: Vaccine boosting or administration of long-acting prophylaxis ( e.g ., monoclonal antibodies) will likely be required to prevent SARS-CoV-2 infection in this susceptible population., Funding: This study was supported by grants and contracts from the NIH (R01 AI157155, R01AI151178, and HHSN75N93019C00074; NIAID Centers of Excellence for Influenza Research and Response (CEIRR) contracts HHSN272201400008C and 75N93021C00014; and Collaborative Influenza Vaccine Innovation Centers [CIVIC] contract 75N93019C00051)., Competing Interests: M.S.D. is a consultant for Inbios, Vir Biotechnology, Senda Biosciences, and Carnival Corporation and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Vir Biotechnology, Moderna, and Emergent BioSolutions. F.K. is a coinventor on a patent application for serological assays and SARS-CoV-2 vaccines (international application numbers PCT/US2021/31110 and 62/994,252). A.H.J.K. participated in consulting, advisory board, or speaker’s bureau for Alexion Pharmaceuticals; Aurinia Pharmaceuticals; Exagen Diagnostics, Inc.; and GlaxoSmithKline and received unrelated funding support under a sponsored research agreement from GlaxoSmithKline. The Ellebedy laboratory received funding under sponsored research agreements that are unrelated to current study from Emergent BioSolutions and AbbVie. A.H.E. is a consultant for Mubadala Investment Company and the founder of ImmuneBio Consulting LLC. A.H.E., M.S.D., and J.S.T. are recipients of a licensing agreement with Abbvie Inc. for commercial development of a SARS-CoV-2 mAb not described in this study. J.S.T. is a consultant for Gerson Lehrman Group. S.C. received research funding from Biogen and received speaking and/or consulting fees from Biogen, Novartis, Sanofi Genzyme, Genentech, and Bristol Myers Squibb. P.D. has participated in consulting, advisory board, or speaker’s bureau for Janssen, Pfizer, Prometheus Biosciences, Boehringer Ingelheim, AbbVie, and Arena Pharmaceuticals and received funding under an unrelated sponsored research agreement from Takeda Pharmaceutical, Arena Pharmaceuticals, Bristol Myers Squibb-Celgene, and Boehringer Ingelheim. G.F.W. has received honoraria for consulting from Novartis and Genentech, Inc. and research funding from Biogen, EMD Serono, and Roche. F.K. has consulted for Merck, Curevac, and Pfizer in the past and is currently consulting for Pfizer, Seqirus, and Avimex. The Krammer laboratory is collaborating with Pfizer on animal models of SARS-CoV-2. G.A. is the founder of SeromYx Systems Inc. and an equity holder of Leyden Labs., (© 2021 Elsevier Inc.)

Although divergent dengue viruses (DENVs) have been isolated in insects, nonhuman primates, and humans, their relationships to the four canonical serotypes (DENV 1-4) are poorly understood. One virus isolated from a dengue patient, DKE-121, falls between genotype and serotype levels of sequence divergence to DENV-4. To examine its antigenic relationship to DENV-4, we assessed serum neutralizing and protective activity. Whereas DENV-4-immune mouse sera neutralize DKE-121 infection, DKE-121-immune sera inhibit DENV-4 less efficiently. Passive transfer of DENV-4 or DKE-121-immune sera protects mice against homologous, but not heterologous, DENV-4 or DKE-121 challenge. Antigenic cartography suggests that DENV-4 and DKE-121 are related but antigenically distinct. However, DENV-4 vaccination confers protection against DKE-121 in nonhuman primates, and serum from humans immunized with a tetravalent vaccine neutralize DENV-4 and DKE-121 infection equivalently. As divergent DENV strains, such as DKE-121, may meet criteria for serotype distinction, monitoring their capacity to impact dengue disease and vaccine efficacy appears warranted., Competing Interests: Declaration of interests M.S.D. is a consultant for Inbios, Vir Biotechnology, and Carnival Corporation and is on the scientific advisory boards of Moderna and Immunome. The Diamond Laboratory has received unrelated funding support in sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions. The Vasilakis laboratory has received unrelated funding support in sponsored research agreements from Public Health Vaccines., (Copyright © 2021 Elsevier Inc. All rights reserved.)

With the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility and potential resistance, antibodies and vaccines with broadly inhibitory activity are needed. Here, we developed a panel of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) that bound the receptor binding domain of the spike protein at distinct epitopes and blocked virus attachment to its host receptor, human angiotensin converting enzyme-2 (hACE2). Although several potently neutralizing mAbs protected K18-hACE2 transgenic mice against infection caused by ancestral SARS-CoV-2 strains, others induced escape variants in vivo or lost neutralizing activity against emerging strains. One mAb, SARS2-38, potently neutralized all tested SARS-CoV-2 variants of concern and protected mice against challenge by multiple SARS-CoV-2 strains. Structural analysis showed that SARS2-38 engaged a conserved epitope proximal to the receptor binding motif. Thus, treatment with or induction of neutralizing antibodies that bind conserved spike epitopes may limit the loss of potency of therapies or vaccines against emerging SARS-CoV-2 variants., Competing Interests: Declaration of interests M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, and Carnival Corporation and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received funding support in sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions. Some of the mAbs described in this study have been licensed by Washington University to Bio X Cell. D.H.F is a founder of Courier Therapeutics and has received funding support in a sponsored research agreement from Emergent BioSolutions. J.E.C. has served as a consultant for Eli Lilly and Luna Biologics, is a member of the Scientific Advisory Boards of CompuVax and Meissa Vaccines, and is the founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received sponsored research agreements from AstraZeneca and IDBiologics. The Boon laboratory has received funding support in sponsored research agreements from AI Therapeutics, GreenLight Biosciences, AbbVie, and Nano Targeting & Therapy Biopharma., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The emergence of SARS-CoV-2 antigenic variants with increased transmissibility is a public health threat. Some variants show substantial resistance to neutralization by SARS-CoV-2 infection- or vaccination-induced antibodies. Here, we analyzed receptor binding domain-binding monoclonal antibodies derived from SARS-CoV-2 mRNA vaccine-elicited germinal center B cells for neutralizing activity against the WA1/2020 D614G SARS-CoV-2 strain and variants of concern. Of five monoclonal antibodies that potently neutralized the WA1/2020 D614G strain, all retained neutralizing capacity against the B.1.617.2 variant, four also neutralized the B.1.1.7 variant, and only one, 2C08, also neutralized the B.1.351 and B.1.1.28 variants. 2C08 reduced lung viral load and morbidity in hamsters challenged with the WA1/2020 D614G, B.1.351, or B.1.617.2 strains. Clonal analysis identified 2C08-like public clonotypes among B cells responding to SARS-CoV-2 infection or vaccination in 41 out of 181 individuals. Thus, 2C08-like antibodies can be induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern., Competing Interests: Declaration of interests The Ellebedy laboratory received funding under sponsored research agreements that are unrelated to the data presented in the current study from Emergent BioSolutions and from AbbVie. A.H.E. is a consultant for Mubadala Investment Company and the founder of ImmuneBio Consulting LLC. M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, Carnival Corporation and on the Scientific Advisory Board of Moderna and Immunome. The Diamond laboratory has received unrelated sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions. The Boon laboratory has received unrelated funding support in sponsored research agreements from AI Therapeutics, GreenLight Biosciences Inc., and Nano targeting & Therapy Biopharma Inc. The Boon laboratory has received funding support from AbbVie Inc., for the commercial development of a SARS-CoV-2 mAb. A.J.S., J.S.T., W.B.A., J.B.C., S.P.J.W., M.S.D., A.C.M.B., and A.H.E. are recipients of a licensing agreement with Abbvie Inc., for commercial development of a SARS-CoV-2 mAb. A patent application related to this work has been filed by Washington University School of Medicine. The Icahn School of Medicine at Mount Sinai has filed patent applications relating to SARS-CoV-2 serological assays and NDV-based SARS-CoV-2 vaccines, which list Florian Krammer as co-inventor. Mount Sinai has spun out a company, Kantaro, to market serological tests for SARS-CoV-2. Florian Krammer has consulted for Merck and Pfizer (before 2020) and is currently consulting for Pfizer, Seqirus, and Avimex. The Krammer laboratory is also collaborating with Pfizer on animal models of SARS-CoV-2. The Shi laboratory has received sponsored research agreements from Pfizer, Gilead, Merck, and IGM Sciences Inc. The Whelan laboratory has received unrelated funding support in sponsored research agreements with Vir Biotechnology, AbbVie, and sAB therapeutics. All other authors declare no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) variants govern transmissibility, responsiveness to vaccination, and disease severity. In a screen for new models of SARS-CoV-2 infection, we identify human H522 lung adenocarcinoma cells as naturally permissive to SARS-CoV-2 infection despite complete absence of angiotensin-converting enzyme 2 (ACE2) expression. Remarkably, H522 infection requires the E484D S variant; viruses expressing wild-type S are not infectious. Anti-S monoclonal antibodies differentially neutralize SARS-CoV-2 E484D S in H522 cells as compared to ACE2-expressing cells. Sera from vaccinated individuals block this alternative entry mechanism, whereas convalescent sera are less effective. Although the H522 receptor remains unknown, depletion of surface heparan sulfates block H522 infection. Temporally resolved transcriptomic and proteomic profiling reveal alterations in cell cycle and the antiviral host cell response, including MDA5-dependent activation of type I interferon signaling. These findings establish an alternative SARS-CoV-2 host cell receptor for the E484D SARS-CoV-2 variant, which may impact tropism of SARS-CoV-2 and consequently human disease pathogenesis., Competing Interests: Declaration of interests S.P.J.W., P.W.R., and Washington University have filed a patent application for uses of VSV-SARS-CoV-2. S.P.J.W. has received unrelated funding support in sponsored research agreements with Vir Biotechnology, Abbvie, and SAB therapeutics. M.S.D. is a consultant for Inbios, Vir Biotechnology, Fortress Biotech, and Carnival Corporation, and is on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received funding support in sponsored research agreements from Moderna, Vir Biotechnology, Kaleido, and Emergent BioSolutions. J.E.C. has served as a consultant for Luna Biologics, is a member of the Scientific Advisory Boards of Meissa Vaccines, and is Founder of IDBiologics. The Crowe laboratory has received sponsored research agreements from Takeda, AstraZeneca, and IDBiologics. Vanderbilt University has applied for patents related to antibodies described in this paper. The remaining authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Most human monoclonal antibodies (mAbs) neutralizing SARS-CoV-2 recognize the spike (S) protein receptor-binding domain and block virus interactions with the cellular receptor angiotensin-converting enzyme 2. We describe a panel of human mAbs binding to diverse epitopes on the N-terminal domain (NTD) of S protein from SARS-CoV-2 convalescent donors and found a minority of these possessed neutralizing activity. Two mAbs (COV2-2676 and COV2-2489) inhibited infection of authentic SARS-CoV-2 and recombinant VSV/SARS-CoV-2 viruses. We mapped their binding epitopes by alanine-scanning mutagenesis and selection of functional SARS-CoV-2 S neutralization escape variants. Mechanistic studies showed that these antibodies neutralize in part by inhibiting a post-attachment step in the infection cycle. COV2-2676 and COV2-2489 offered protection either as prophylaxis or therapy, and Fc effector functions were required for optimal protection. Thus, natural infection induces a subset of potent NTD-specific mAbs that leverage neutralizing and Fc-mediated activities to protect against SARS-CoV-2 infection using multiple functional attributes., Competing Interests: Declaration of interests M.E.F., E.D., and B.J.D. are employees of Integral Molecular. B.J.D. is a shareholder of Integral Molecular. M.S.D. is a consultant for Inbios, Vir Biotechnology, NGM Biopharmaceuticals, and Carnival Corporation and is on the Scientific Advisory Boards of Moderna and Immunome, and the Diamond laboratory at Washington University School of Medicine has received sponsored research agreements from Emergent BioSolutions, Moderna, and Vir Biotechnology. J.E.C. has served as a consultant for Eli Lilly, GlaxoSmithKline, and Luna Biologics, is a member of the Scientific Advisory Boards of CompuVax and Meissa Vaccines, and is founder of IDBiologics. The Crowe laboratory at Vanderbilt University Medical Center has received unrelated sponsored research agreements from IDBiologics and AstraZeneca., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Neutralizing antibodies against the SARS-CoV-2 spike (S) protein are a goal of COVID-19 vaccines and have received emergency use authorization as therapeutics. However, viral escape mutants could compromise efficacy. To define immune-selected mutations in the S protein, we exposed a VSV-eGFP-SARS-CoV-2-S chimeric virus, in which the VSV glycoprotein is replaced with the S protein, to 19 neutralizing monoclonal antibodies (mAbs) against the receptor-binding domain (RBD) and generated 50 different escape mutants. Each mAb had a unique resistance profile, although many shared residues within an epitope of the RBD. Some variants (e.g., S477N) were resistant to neutralization by multiple mAbs, whereas others (e.g., E484K) escaped neutralization by convalescent sera. Additionally, sequential selection identified mutants that escape neutralization by antibody cocktails. Comparing these antibody-mediated mutations with sequence variation in circulating SARS-CoV-2 revealed substitutions that may attenuate neutralizing immune responses in some humans and thus warrant further investigation., Competing Interests: Declaration of interests M.S.D. is a consultant for Inbios, Vir Biotechnology, and NGM Biopharmaceuticals, and is on the scientific advisory board of Moderna and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions. The Ellebedy laboratory has received unrelated funding support in sponsored research agreements from Emergent BioSolutions, and funding support in sponsored research agreements from AbbVie to further develop 2B04 and 2H04 as therapeutic mAbs. A.H.E. and Washington University have filed a patent application that includes the SARS-CoV-2 antibodies 2B04 and 2H04 for potential commercial development. S.P.J.W. and Z.L. have filed a disclosure with Washington University for VSV-SARS-CoV-2 mutants to characterize antibody panels. S.P.J.W. and Washington University have filed a patent application on VSV-SARS-CoV-2. S.P.J.W has received unrelated funding support in sponsored research agreements with Vir Biotechnology, AbbVie, and sAB therapeutics., (Copyright © 2021. Published by Elsevier Inc.)

The coronavirus disease 2019 pandemic has made deployment of an effective vaccine a global health priority. We evaluated the protective activity of a chimpanzee adenovirus-vectored vaccine encoding a prefusion stabilized spike protein (ChAd-SARS-CoV-2-S) in challenge studies with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mice expressing the human angiotensin-converting enzyme 2 receptor. Intramuscular dosing of ChAd-SARS-CoV-2-S induces robust systemic humoral and cell-mediated immune responses and protects against lung infection, inflammation, and pathology but does not confer sterilizing immunity, as evidenced by detection of viral RNA and induction of anti-nucleoprotein antibodies after SARS-CoV-2 challenge. In contrast, a single intranasal dose of ChAd-SARS-CoV-2-S induces high levels of neutralizing antibodies, promotes systemic and mucosal immunoglobulin A (IgA) and T cell responses, and almost entirely prevents SARS-CoV-2 infection in both the upper and lower respiratory tracts. Intranasal administration of ChAd-SARS-CoV-2-S is a candidate for preventing SARS-CoV-2 infection and transmission and curtailing pandemic spread., Competing Interests: Declaration of Interests M.S.D. is a consultant for Inbios, Vir Biotechnology, and NGM Biopharmaceuticals and on the Scientific Advisory Board of Moderna. The Diamond laboratory has received unrelated funding support from Moderna, Vir Biotechnology, and Emergent BioSolutions. M.S.D., D.T.C., A.O.H., and I.P.D. have filed a disclosure with Washington University for possible development of ChAd-SARS-CoV-2. M.J.H. is a member of the DSMB for AstraZeneca and founder of NuPeak Therapeutics. The Baric laboratory has received unrelated funding support from Takeda, Pfizer, and Eli Lilly., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Powassan virus (POWV) is an emerging tick-transmitted flavivirus that circulates in North America and Russia. Up to 5% of deer ticks now test positive for POWV in certain regions of the northern United States. Although POWV infections cause life-threatening encephalitis, there is no vaccine or countermeasure available for prevention or treatment. Here, we developed a lipid nanoparticle (LNP)-encapsulated modified mRNA vaccine encoding the POWV prM and E genes and demonstrated its immunogenicity and efficacy in mice following immunization with one or two doses. The POWV mRNA vaccine induced high titers of neutralizing antibody and sterilizing immunity against lethal challenge with different POWV strains. The mRNA vaccine also induced cross-neutralizing antibodies against multiple other tick-borne flaviviruses and protected mice against the distantly related Langat virus. These data demonstrate the utility of the LNP-mRNA vaccine platform for the development of vaccines with protective activity against multiple flaviviruses., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Although interferon-induced proteins with tetratricopeptide repeats (IFIT proteins) inhibit infection of many viruses by recognizing their RNA, the regulatory mechanisms involved remain unclear. Here we report a crystal structure of cap 0 (m 7 GpppN) RNA bound to human IFIT1 in complex with the C-terminal domain of human IFIT3. Structural, biochemical, and genetic studies suggest that IFIT3 binding to IFIT1 has dual regulatory functions: (1) extending the half-life of IFIT1 and thereby increasing its steady-state amounts in cells; and (2) allosterically regulating the IFIT1 RNA-binding channel, thereby enhancing the specificity of recognition for cap 0 but not cap 1 (m 7 GpppNm) or 5'-ppp RNA. Mouse Ifit3 lacks this key C-terminal domain and does not bind mouse Ifit1. The IFIT3 interaction with IFIT1 is important for restricting infection of viruses lacking 2'-O methylation in their RNA cap structures. Our experiments establish differences in the regulation of IFIT1 orthologs and define targets for modulation of human IFIT protein activity., (Copyright © 2018 Elsevier Inc. All rights reserved.)