Evaluation of Human Monoclonal Antibody 80R for Immunoprophylaxis of Severe Acute Respiratory Syndrome by an Animal Study, Epitope Mapping, and Analysis of Spike Variants

Sui, Jianhua; Li, Wenhui; Roberts, Anjeanette; Matthews, Leslie J.; Murakami, Akikazu; Vogel, Leatrice; Wong, Sharon; Subbarao, Kanta; Farzan, Michael; Marasco, Wayne A.

doi:10.1128/jvi.79.10.5900-5906.2005

Cited by 150 publications

(203 citation statements)

References 31 publications

(38 reference statements)

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“…The high apparent affinity (avidity) observed for IgG1 m369 is due to the effective multivalency of the surface-associated antigen binding to the bivalent IgG1. Further, we found that the antibody potently inhibited 1) cell fusion and pseudovirus entry mediated by the SCV (Tor2 isolate) S glycoprotein with an IC 50 of 0.6 and 0.01 g/ml, respectively, 2) SCV entry mediated by the S glycoprotein from the GD03T0013 isolate, which is not neutralizable by other known human monoclonal antibodies, including 80R (29,30) and S3.1 (31,32), and 3) live virus from Urbani and Tor2 isolates with an IC 50 of 0.1 and 1 g/ml, respectively. 6 The structure of the SCV RBD-Fab m396 complex is depicted in Fig.…”

Section: Resultsmentioning

confidence: 88%

Structure of Severe Acute Respiratory Syndrome Coronavirus Receptor-binding Domain Complexed with Neutralizing Antibody

Prabakaran

Gan

Yang

et al. 2006

Journal of Biological Chemistry

251

297

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The severe acute respiratory syndrome coronavirus (SARSCoV, or SCV), which caused a world-wide epidemic in 2002 and 2003, binds to a receptor, angiotensin-converting enzyme 2 (ACE2), through the receptor-binding domain (RBD) of its envelope (spike, S) glycoprotein. The RBD is very immunogenic; it is a major SCV neutralization determinant and can elicit potent neutralizing antibodies capable of out-competing ACE2. However, the structural basis of RBD immunogenicity, RBD-mediated neutralization, and the role of RBD in entry steps following its binding to ACE2 have not been elucidated. By mimicking immune responses with the use of RBD as an antigen to screen a large human antibody library derived from healthy volunteers, we identified a novel potent cross-reactive SCV-neutralizing monoclonal antibody, m396, which competes with ACE2 for binding to RBD, and determined the crystal structure of the RBD-antibody complex at 2.3-Å resolution. The antibody-bound RBD structure is completely defined, revealing two previously unresolved segments (residues 376 -381 and 503-512) and a new disulfide bond (between residues 378 and 511). Interestingly, the overall structure of the m396-bound RBD is not significantly different from that of the ACE2-bound RBD. The antibody epitope is dominated by a 10-residue-long protruding ␤6 -␤7 loop with two putative ACE2-binding hotspot residues (Ile-489 and Tyr-491). These results provide a structural rationale for the function of a major determinant of SCV immunogenicity and neutralization, the development of SCV therapeutics based on the antibody paratope and epitope, and a retrovaccinology approach for the design of anti-SCV vaccines. The available structural information indicates that the SCV entry may not be mediated by ACE2-induced conformational changes in the RBD but may involve other conformational changes or/and yet to be identified coreceptors.The severe acute respiratory syndrome coronavirus (SARS-CoV, or SCV) 4 infected more than 8000 humans with a fatality rate of ϳ10% (1-4). Although there have been no recent outbreaks, the need to develop potent therapeutics and vaccines against a re-emerging SCV or a related virus remains of high priority. The amazingly rapid pace of SARS research for the last few years has resulted in a wealth of information for the virus, especially about its interactions with the host leading to disease and immune responses, which could also be helpful for the development of strategies to cope with other viral pathogens including influenza and HIV.Entry of viruses into animal cells is initiated by binding to cell-surface-associated receptors and can be prevented by neutralizing antibodies (nAbs) targeting the virus receptor-binding site (5, 6). In the case of SCV entry, the spike (S) glycoprotein (7, 8) binds to a receptor, angiotensin-converting enzyme 2 (ACE2) (9), through the receptor-binding site of its receptor-binding domain (RBD) (7, 10, 11). The RBD is an attractive target for neutralizing antibodies that could prevent SCV entry by blocking the a...

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Section: Resultsmentioning

confidence: 88%

Structure of Severe Acute Respiratory Syndrome Coronavirus Receptor-binding Domain Complexed with Neutralizing Antibody

Prabakaran

Gan

Yang

et al. 2006

Journal of Biological Chemistry

251

297

View full text Add to dashboard Cite

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“…Its epitope overlaps the binding site of the SARS-CoV receptor ACE2, suggesting a possible mechanism of neutralization by preventing the virus attachment to its receptor (19). This antibody was further tested with a pseudovirus assay; it inhibited Tor2 isolate with an IC 90 of Ϸ2 g/ml but had no effect on the GD03 isolate (20). The neutralizing activity of this antibody in our cell fusion assay was about 2-fold lower compared with that of m396 (IC 50 ϭ 1.1 vs. 0.6 g/ml) for the Tor2 isolate.…”

Section: Discussionmentioning

confidence: 99%

“…However, data demonstrating activities of any of the identified hmAbs against isolates from the second SARS outbreak and isolates of closely related viruses isolated from animals have yet to be published. Recently, it was found that the GD03 strain, isolated from the first patient of the second (2003/ 2004) outbreak, is resistant to neutralization by two of the previously characterized hmAbs, 80R and S3.1 (18)(19)(20)27).…”

mentioning

confidence: 99%

Potent cross-reactive neutralization of SARS coronavirus isolates by human monoclonal antibodies

Zhu

Chakraborti

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…Several of the S mutations fall within the RBD as well as other regions shown to elicit neutralizing antibodies (24,28,57). To study the effect of these mutations on the ability of monoclonal antibodies to neutralize both homologous and heterologous viruses, SARS-CoV isolates bearing the spike variants were incubated with murine monoclonal antibodies previously shown to neutralize the Urbani isolate (58).…”

Section: Selection Of Representative Spike Variants Of Sars-covmentioning

confidence: 99%

Synthetic Reconstruction of Zoonotic and Early Human Severe Acute Respiratory Syndrome Coronavirus Isolates That Produce Fatal Disease in Aged Mice

Rockx

Sheahan

Donaldson

et al. 2007

J Virol

108

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The severe acute respiratory syndrome (SARS) epidemic was characterized by high mortality rates in the elderly. The molecular mechanisms that govern enhanced susceptibility of elderly populations are not known, and robust animal models are needed that recapitulate the increased pathogenic phenotype noted with increasing age. Using synthetic biology and reverse genetics, we describe the construction of a panel of isogenic SARS coronavirus (SARS-CoV) strains bearing variant spike glycoproteins that are representative of zoonotic strains found in palm civets and raccoon dogs, as well as isolates spanning the early, middle, and late phases of the SARS-CoV epidemic. The recombinant viruses replicated efficiently in cell culture and demonstrated variable sensitivities to neutralization with antibodies. The human but not the zoonotic variants replicated efficiently in human airway epithelial cultures, supporting earlier hypotheses that zoonotic isolates are less pathogenic in humans but can evolve into highly pathogenic strains. All viruses replicated efficiently, but none produced clinical disease or death in young animals. In contrast, severe clinical disease, diffuse alveolar damage, hyaline membrane formation, alveolitis, and death were noted in 12-month-old mice inoculated with the palm civet HC/SZ/61/03 strain or early-human-phase GZ02 variants but not with related middle-and late-phase epidemic or raccoon dog strains. This panel of SARS-CoV recombinants bearing zoonotic and human epidemic spike glycoproteins will provide heterologous challenge models for testing vaccine efficacy against zoonotic reintroductions as well as provide the appropriate model system for elucidating the complex virus-host interactions that contribute to more-severe and fatal SARS-CoV disease and acute respiratory distress in the elderly.

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Evaluation of Human Monoclonal Antibody 80R for Immunoprophylaxis of Severe Acute Respiratory Syndrome by an Animal Study, Epitope Mapping, and Analysis of Spike Variants

Cited by 150 publications

References 31 publications

Structure of Severe Acute Respiratory Syndrome Coronavirus Receptor-binding Domain Complexed with Neutralizing Antibody

Structure of Severe Acute Respiratory Syndrome Coronavirus Receptor-binding Domain Complexed with Neutralizing Antibody

Potent cross-reactive neutralization of SARS coronavirus isolates by human monoclonal antibodies

Synthetic Reconstruction of Zoonotic and Early Human Severe Acute Respiratory Syndrome Coronavirus Isolates That Produce Fatal Disease in Aged Mice

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