InVivoMAb anti-SARS-CoV-2 S protein (RBD)

Catalog #BE0438
Clone:
SARS2-38
Reactivities:
Virus

$164.00 - $4,280.00

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  • 1 mg - $164.00
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Product Details

The SARS2-38 monoclonal antibody reacts with many variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). SARS-CoV-2 vaccines and neutralizing monoclonal antibodies have been great tools for controlling the COVID-19 pandemic however, the emerging SARS-CoV-2 variants often exhibit mutations in the spike protein, conferring resistance to antibodies elicited by vaccines or natural infections. The SARS2-38 monoclonal antibody binds a conserved epitope on the RBD (amino acids K444 and G446). Targeting this conserved region with SARS-CoV-2 vaccines or neutralizing antibodies is suggested to confer protection against infections with SARS-CoV-2 variants. The SARS2-38 monoclonal antibody is a potently neutralizing antibody that does not cross-react with the SARS-CoV-1 spike protein. The SARS2-38 monoclonal antibody is reported to inhibit the attachment of SARS-CoV-2 to Vero E6, Vero-TMPRSS2, Vero-TMPRSS2-ACE2, or Calu-3 cells and the virus internalization in Vero E6 cells in vitro. In animal studies, a single 100-μg in vivo injection of SARS2-38 monoclonal antibody to K18 human ACE2 (hACE2) transgenic mice 24 hours before the intranasal inoculation of SARS-CoV-2 WA1/2020 decreased the levels of viral RNA, cytokines, and chemokines.

Specifications

Isotype Mouse IgG1, κ
Recommended Isotype Control(s) InVivoMAb mouse IgG1 isotype control, unknown specificity
Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Immunogen SARS-CoV-2 RBD and SARS-CoV-2 spike protein
Reported Applications in vivo neutralization of SARS-CoV-2 variants
in vitro neutralization of SARS-CoV-2 variants
Focus reduction neutralization test (FRNT)
Flow cytometry
ELISA
Inhibition of viral attachment on cells
Focus forming assay (FFA)
Formulation PBS, pH 7.0
Contains no stabilizers or preservatives
Endotoxin <2EU/mg (<0.002EU/μg)
Determined by LAL gel clotting assay
Purity >95%
Determined by SDS-PAGE
Sterility 0.2 µm filtration
Production Purified from cell culture supernatant in an animal-free facility
Purification Protein G
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.
in vitro neutralization of SARS-CoV-2 variants
Hunt AC, Vögeli B, Hassan AO, Guerrero L, Kightlinger W, Yoesep DJ, Krüger A, DeWinter M, Diamond MS, Karim AS, Jewett MC. (2023). "A rapid cell-free expression and screening platform for antibody discovery" Nat Commun 10.1038/s41467-023-38965-w. PubMed

Antibody discovery is bottlenecked by the individual expression and evaluation of antigen-specific hits. Here, we address this bottleneck by developing a workflow combining cell-free DNA template generation, cell-free protein synthesis, and binding measurements of antibody fragments in a process that takes hours rather than weeks. We apply this workflow to evaluate 135 previously published antibodies targeting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including all 8 antibodies previously granted emergency use authorization for coronavirus disease 2019 (COVID-19), and demonstrate identification of the most potent antibodies. We also evaluate 119 anti-SARS-CoV-2 antibodies from a mouse immunized with the SARS-CoV-2 spike protein and identify neutralizing antibody candidates, including the antibody SC2-3, which binds the SARS-CoV-2 spike protein of all tested variants of concern. We expect that our cell-free workflow will accelerate the discovery and characterization of antibodies for future pandemics and for research, diagnostic, and therapeutic applications more broadly.

in vitro neutralization of SARS-CoV-2 variants, Inhibition of viral attachment on cells, Flow Cytometry
Adams LJ, VanBlargan LA, Liu Z, Gilchuk P, Zhao H, Chen RE, Raju S, Chong Z, Whitener BM, Shrihari S, Jethva PN, Gross ML, Crowe JE, Whelan SPJ, Diamond MS, Fremont DH. (2023). "A broadly reactive antibody targeting the N-terminal domain of SARS-CoV-2 spike confers Fc-mediated protection" Cell Rep Med 10.1016/j.xcrm.2023.101305. PubMed

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.

Focus reduction neutralization test (FRNT)
Zhang JZ, Yeh HW, Walls AC, Wicky BIM, Sprouse KR, VanBlargan LA, Treger R, Quijano-Rubio A, Pham MN, Kraft JC, Haydon IC, Yang W, DeWitt M, Bowen JE, Chow CM, Carter L, Ravichandran R, Wener MH, Stewart L, Veesler D, Diamond MS, Greninger AL, Koelle DM, Baker D. (2022). "Thermodynamically coupled biosensors for detecting neutralizing antibodies against SARS-CoV-2 variants" Nat Biotechnol 10.1038/s41587-022-01280-8. PubMed

We designed a protein biosensor that uses thermodynamic coupling for sensitive and rapid detection of neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in serum. The biosensor is a switchable, caged luciferase-receptor-binding domain (RBD) construct that detects serum-antibody interference with the binding of virus RBD to angiotensin-converting enzyme 2 (ACE-2) as a proxy for neutralization. Our coupling approach does not require target modification and can better distinguish sample-to-sample differences in analyte binding affinity and abundance than traditional competition-based assays.

Focus reduction neutralization test (FRNT)
Gilchuk P, Thomsen I, Yoder S, Brady E, Chappell JD, Stevens LJ, Denison MR, Sutton RE, Chen RE, VanBlargan LA, Suryadevara N, Zost SJ, Schmitz J, Pulley JM, Diamond MS, Rhoads JP, Bernard GR, Self WH, Rice TW, Wheeler AP, Crowe JE, Carnahan RH. (2022). "Standardized two-step testing of antibody activity in COVID-19 convalescent plasma" iScience 10.1016/j.isci.2021.103602. PubMed

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.

Focus reduction neutralization test (FRNT)
Ying B, Scheaffer SM, Whitener B, Liang CY, Dmytrenko O, Mackin S, Wu K, Lee D, Avena LE, Chong Z, Case JB, Ma L, Kim TTM, Sein CE, Woods A, Berrueta DM, Chang GY, Stewart-Jones G, Renzi I, Lai YT, Malinowski A, Carfi A, Elbashir SM, Edwards DK, Thackray LB, Diamond MS. (2022). "Boosting with variant-matched or historical mRNA vaccines protects against Omicron infection in mice" Cell 10.1016/j.cell.2022.03.037. PubMed

The large number of spike substitutions in Omicron lineage variants (BA.1, BA.1.1., and BA.2) could jeopardize the efficacy of SARS-CoV-2 vaccines. We evaluated in mice the protective efficacy of the Moderna mRNA-1273 vaccine against BA.1 before or after boosting. Whereas two doses of mRNA-1273 vaccine induced high levels of neutralizing antibodies against historical WA1/2020 strains, lower levels against BA.1 were associated with breakthrough infection and inflammation in the lungs. A primary vaccination series with mRNA-1273.529, an Omicron-matched vaccine, potently neutralized BA.1 but inhibited historical or other SARS-CoV-2 variants less effectively. However, boosting with either mRNA-1273 or mRNA-1273.529 vaccines increased neutralizing titers and protection against BA.1 and BA.2 infection. Nonetheless, the neutralizing antibody titers were higher, and lung viral burden and cytokines were slightly lower in mice boosted with mRNA-1273.529 and challenged with BA.1. Thus, boosting with mRNA-1273 or mRNA-1273.529 enhances protection against Omicron infection with limited differences in efficacy measured.

Focus reduction neutralization test (FRNT)
Walls AC, VanBlargan LA, Wu K, Choi A, Navarro MJ, Lee D, Avena L, Berrueta DM, Pham MN, Elbashir S, Kraft JC, Miranda MC, Kepl E, Johnson M, Blackstone A, Sprouse K, Fiala B, O', Connor MA, Brunette N, Arunachalam PS, Shirreff L, Rogers K, Carter L, Fuller DH, Villinger F, Pulendran B, Diamond MS, Edwards DK, King NP, Veesler D. (2022). "Distinct sensitivities to SARS-CoV-2 variants in vaccinated humans and mice" Cell Rep 10.1016/j.celrep.2022.111299. PubMed

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.

Focus forming assay (FFA)
Winkler ES, Chen RE, Alam F, Yildiz S, Case JB, Uccellini MB, Holtzman MJ, Garcia-Sastre A, Schotsaert M, Diamond MS. (2022). "SARS-CoV-2 Causes Lung Infection without Severe Disease in Human ACE2 Knock-In Mice" J Virol 10.1128/JVI.01511-21. PubMed

The development of mouse models for coronavirus disease 2019 (COVID-19) has enabled testing of vaccines and therapeutics and defining aspects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis. SARS-CoV-2 disease is severe in K18 transgenic mice (K18-hACE2 Tg) expressing human angiotensin-converting enzyme 2 (hACE2), the SARS-CoV-2 receptor, under an ectopic cytokeratin promoter, with high levels of infection measured in the lung and brain. Here, we evaluated SARS-CoV-2 infection in hACE2 knock-in (KI) mice that express hACE2 under an endogenous promoter in place of murine ACE2 (mACE2). Intranasal inoculation of hACE2 KI mice with SARS-CoV-2 WA1/2020 resulted in substantial viral replication within the upper and lower respiratory tracts with limited spread to extrapulmonary organs. However, SARS-CoV-2-infected hACE2 KI mice did not lose weight and developed limited pathology. Moreover, no significant differences in viral burden were observed in hACE2 KI mice infected with B.1.1.7 or B.1.351 variants compared to the WA1/2020 strain. Because the entry mechanisms of SARS-CoV-2 in mice remain uncertain, we evaluated the impact of the naturally occurring, mouse-adapting N501Y mutation by comparing infection of hACE2 KI, K18-hACE2 Tg, ACE2-deficient, and wild-type C57BL/6 mice. The N501Y mutation minimally affected SARS-CoV-2 infection in hACE2 KI mice but was required for viral replication in wild-type C57BL/6 mice in a mACE2-dependent manner and augmented pathogenesis in the K18-hACE2 Tg mice. Thus, the N501Y mutation likely enhances interactions with mACE2 or hACE2 in vivo. Overall, our study highlights the hACE2 KI mice as a model of mild SARS-CoV-2 infection and disease and clarifies the requirement of the N501Y mutation in mice. IMPORTANCE Mouse models of SARS-CoV-2 pathogenesis have facilitated the rapid evaluation of countermeasures. While the first generation of models developed pneumonia and severe disease after SARS-CoV-2 infection, they relied on ectopic expression of supraphysiological levels of human ACE2 (hACE2). This has raised issues with their relevance to humans, as the hACE2 receptor shows a more restricted expression pattern in the respiratory tract. Here, we evaluated SARS-CoV-2 infection and disease with viruses containing or lacking a key mouse-adapting mutation in the spike gene in hACE2 KI mice, which express hACE2 under an endogenous promoter in place of murine ACE2. While infection of hACE2 KI mice with multiple strains of SARS-CoV-2 including variants of concern resulted in viral replication within the upper and lower respiratory tracts, the animals did not sustain severe lung injury. Thus, hACE2 KI mice serve as a model of mild infection with both ancestral and emerging SARS-CoV-2 variant strains.

in vivo neutralization of SARS-CoV-2 variants, in vitro neutralization of SARS-CoV-2 variants, Focus reduction neutralization test (FRNT), Flow Cytometry, ELISA
VanBlargan LA, Adams LJ, Liu Z, Chen RE, Gilchuk P, Raju S, Smith BK, Zhao H, Case JB, Winkler ES, Whitener BM, Droit L, Aziati ID, Bricker TL, Joshi A, Shi PY, Creanga A, Pegu A, Handley SA, Wang D, Boon ACM, Crowe JE, Whelan SPJ, Fremont DH, Diamond MS. (2021). "A potently neutralizing SARS-CoV-2 antibody inhibits variants of concern by utilizing unique binding residues in a highly conserved epitope" Immunity 10.1016/j.immuni.2021.08.016. PubMed

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.

Focus reduction neutralization test (FRNT)
Turner JS, O', Halloran JA, Kalaidina E, Kim W, Schmitz AJ, Zhou JQ, Lei T, Thapa M, Chen RE, Case JB, Amanat F, Rauseo AM, Haile A, Xie X, Klebert MK, Suessen T, Middleton WD, Shi PY, Krammer F, Teefey SA, Diamond MS, Presti RM, Ellebedy AH. (2021). "SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses" Nature 10.1038/s41586-021-03738-2. PubMed

SARS-CoV-2 mRNA-based vaccines are about 95% effective in preventing COVID-191-5. The dynamics of antibody-secreting plasmablasts and germinal centre B cells induced by these vaccines in humans remain unclear. Here we examined antigen-specific B cell responses in peripheral blood (n = 41) and draining lymph nodes in 14 individuals who had received 2 doses of BNT162b2, an mRNA-based vaccine that encodes the full-length SARS-CoV-2 spike (S) gene1. Circulating IgG- and IgA-secreting plasmablasts that target the S protein peaked one week after the second immunization and then declined, becoming undetectable three weeks later. These plasmablast responses preceded maximal levels of serum anti-S binding and neutralizing antibodies to an early circulating SARS-CoV-2 strain as well as emerging variants, especially in individuals who had previously been infected with SARS-CoV-2 (who produced the most robust serological responses). By examining fine needle aspirates of draining axillary lymph nodes, we identified germinal centre B cells that bound S protein in all participants who were sampled after primary immunization. High frequencies of S-binding germinal centre B cells and plasmablasts were sustained in these draining lymph nodes for at least 12 weeks after the booster immunization. S-binding monoclonal antibodies derived from germinal centre B cells predominantly targeted the receptor-binding domain of the S protein, and fewer clones bound to the N-terminal domain or to epitopes shared with the S proteins of the human betacoronaviruses OC43 and HKU1. These latter cross-reactive B cell clones had higher levels of somatic hypermutation as compared to those that recognized only the SARS-CoV-2 S protein, which suggests a memory B cell origin. Our studies demonstrate that SARS-CoV-2 mRNA-based vaccination of humans induces a persistent germinal centre B cell response, which enables the generation of robust humoral immunity.

Focus reduction neutralization test (FRNT)
Ying B, Whitener B, VanBlargan LA, Hassan AO, Shrihari S, Liang CY, Karl CE, Mackin S, Chen RE, Kafai NM, Wilks SH, Smith DJ, Carreño JM, Singh G, Krammer F, Carfi A, Elbashir S, Edwards DK, Thackray LB, Diamond MS. (2021). "Protective activity of mRNA vaccines against ancestral and variant SARS-CoV-2 strains" bioRxiv 10.1101/2021.08.25.457693. PubMed

Although mRNA vaccines prevent COVID-19, variants jeopardize their efficacy as immunity wanes. Here, we assessed the immunogenicity and protective activity of historical (mRNA-1273, designed for Wuhan-1 spike) or modified (mRNA-1273.351, designed for B.1.351 spike) preclinical Moderna mRNA vaccines in 129S2 and K18-hACE2 mice. Immunization with high or low dose formulations of mRNA vaccines induced neutralizing antibodies in serum against ancestral SARS-CoV-2 and several variants, although levels were lower particularly against the B.1.617.2 (Delta) virus. Protection against weight loss and lung pathology was observed with all high-dose vaccines against all viruses. Nonetheless, low-dose formulations of the vaccines, which produced lower magnitude antibody and T cell responses, and serve as a possible model for waning immunity, showed breakthrough lung infection and pneumonia with B.1.617.2. Thus, as levels of immunity induced by mRNA vaccines decline, breakthrough infection and disease likely will occur with some SARS-CoV-2 variants, suggesting a need for additional booster regimens.

in vitro neutralization of SARS-CoV-2 variants
Liu Z, VanBlargan LA, Bloyet LM, Rothlauf PW, Chen RE, Stumpf S, Zhao H, Errico JM, Theel ES, Liebeskind MJ, Alford B, Buchser WJ, Ellebedy AH, Fremont DH, Diamond MS, Whelan SPJ. (2021). "Identification of SARS-CoV-2 spike mutations that attenuate monoclonal and serum antibody neutralization" Cell Host Microbe 10.1016/j.chom.2021.01.014. PubMed

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.

in vitro neutralization of SARS-CoV-2 variants
Zhang JZ, Yeh HW, Walls AC, Wicky BIM, Sprouse K, VanBlargan LA, Treger R, Quijano-Rubio A, Pham MN, Kraft JC, Haydon IC, Yang W, DeWitt M, Chow C, Carter L, Wener MH, Stewart L, Veesler D, Diamond MS, Baker D. (2021). "Detection of antibodies neutralizing historical and emerging SARS-CoV-2 strains using a thermodynamically coupled de novo biosensor system" bioRxiv 10.1101/2021.06.22.449355. PubMed

With global vaccination efforts against SARS-CoV-2 underway, there is a need for rapid quantification methods for neutralizing antibodies elicited by vaccination and characterization of their strain dependence. Here, we describe a designed protein biosensor that enables sensitive and rapid detection of neutralizing antibodies against wild type and variant SARS-CoV-2 in serum samples. More generally, our thermodynamic coupling approach can better distinguish sample to sample differences in analyte binding affinity and abundance than traditional competition based assays.

in vitro neutralization of SARS-CoV-2 variants
Hassan AO, Shrihari S, Gorman MJ, Ying B, Yuan D, Raju S, Chen RE, Dmitriev IP, Kashentseva E, Adams LJ, Mann C, Davis-Gardner ME, Suthar MS, Shi PY, Saphire EO, Fremont DH, Curiel DT, Alter G, Diamond MS. (2021). "An intranasal vaccine durably protects against SARS-CoV-2 variants in mice" Cell Rep 10.1016/j.celrep.2021.109452. PubMed

SARS-CoV-2 variants that attenuate antibody neutralization could jeopardize vaccine efficacy. We recently reported the protective activity of an intranasally administered spike protein-based chimpanzee adenovirus-vectored vaccine (ChAd-SARS-CoV-2-S) in animals, which has advanced to human trials. Here, we assessed its durability, dose response, and cross-protective activity in mice. A single intranasal dose of ChAd-SARS-CoV-2-S induced durably high neutralizing and Fc effector antibody responses in serum and S-specific IgG and IgA secreting long-lived plasma cells in the bone marrow. Protection against a historical SARS-CoV-2 strain was observed across a 100-fold vaccine dose range and over a 200-day period. At 6 weeks or 9 months after vaccination, serum antibodies neutralized SARS-CoV-2 strains with B.1.351, B.1.1.28, and B.1.617.1 spike proteins and conferred almost complete protection in the upper and lower respiratory tracts after challenge with variant viruses. Thus, in mice, intranasal immunization with ChAd-SARS-CoV-2-S provides durable protection against historical and emerging SARS-CoV-2 strains.

Focus reduction neutralization test (FRNT)
Chen RE, Gorman MJ, Zhu DY, Carreño JM, Yuan D, VanBlargan LA, Burdess S, Lauffenburger DA, Kim W, Turner JS, Droit L, Handley SA, Chahin S, Deepak P, O', Halloran JA, Paley MA, Presti RM, Wu GF, Krammer F, Alter G, Ellebedy AH, Kim AHJ, Diamond MS. (2021). "Reduced antibody activity against SARS-CoV-2 B.1.617.2 delta virus in serum of mRNA-vaccinated individuals receiving tumor necrosis factor-α inhibitors" Med 10.1016/j.medj.2021.11.004. PubMed

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).

Focus reduction neutralization test (FRNT)
Case JB, Chen RE, Cao L, Ying B, Winkler ES, Johnson M, Goreshnik I, Pham MN, Shrihari S, Kafai NM, Bailey AL, Xie X, Shi PY, Ravichandran R, Carter L, Stewart L, Baker D, Diamond MS. (2021). "Ultrapotent miniproteins targeting the SARS-CoV-2 receptor-binding domain protect against infection and disease" Cell Host Microbe 10.1016/j.chom.2021.06.008. PubMed

Despite the introduction of public health measures and spike protein-based vaccines to mitigate the COVID-19 pandemic, SARS-CoV-2 infections and deaths continue to have a global impact. Previously, we used a structural design approach to develop picomolar range miniproteins targeting the SARS-CoV-2 spike receptor-binding domain. Here, we investigated the capacity of modified versions of one lead miniprotein, LCB1, to protect against SARS-CoV-2-mediated lung disease in mice. Systemic administration of LCB1-Fc reduced viral burden, diminished immune cell infiltration and inflammation, and completely prevented lung disease and pathology. A single intranasal dose of LCB1v1.3 reduced SARS-CoV-2 infection in the lung when given as many as 5 days before or 2 days after virus inoculation. Importantly, LCB1v1.3 protected in vivo against a historical strain (WA1/2020), an emerging B.1.1.7 strain, and a strain encoding key E484K and N501Y spike protein substitutions. These data support development of LCB1v1.3 for prevention or treatment of SARS-CoV-2 infection.

Flow Cytometry
Hassan AO, Kafai NM, Dmitriev IP, Fox JM, Smith BK, Harvey IB, Chen RE, Winkler ES, Wessel AW, Case JB, Kashentseva E, McCune BT, Bailey AL, Zhao H, VanBlargan LA, Dai YN, Ma M, Adams LJ, Shrihari S, Danis JE, Gralinski LE, Hou YJ, Schäfer A, Kim AS, Keeler SP, Weiskopf D, Baric RS, Holtzman MJ, Fremont DH, Curiel DT, Diamond MS. (2020). "A Single-Dose Intranasal ChAd Vaccine Protects Upper and Lower Respiratory Tracts against SARS-CoV-2" Cell 10.1016/j.cell.2020.08.026. PubMed

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.