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Sensitivity of infectious SARS-CoV-2 B.1.1.7 and B.1.351 variants to neutralizing antibodies

Delphine Planas 1, 2 Timothée Bruel 1, 2 Ludivine Grzelak 1, 2, 3 Florence Guivel-Benhassine 1, 2 Isabelle Staropoli 1, 2 Françoise Porrot 1, 2 Cyril Planchais 4 Julian Buchrieser 1, 2 Maaran Michael Rajah 1, 2, 3 Elodie Bishop 1, 2, 3 Mélanie Albert 5, 6 Flora Donati 6, 5 Matthieu Prot 7 Sylvie Behillil 6, 5 Vincent Enouf 6, 5 Marianne Maquart 8 Mounira Smati-Lafarge 9 Emmanuelle Varon 9 Frédérique Schortgen 9 Layla Yahyaoui 9 Maria Gonzalez 10 Jérôme de Sèze 11 Hélène Péré 12 David Veyer 12, 13 Aymeric Sève 14 Etienne Simon-Lorière 7 Samira Fafi-Kremer 10, 15 Karl Stefic 8, 16 Hugo Mouquet 4 Laurent Hocqueloux 14 Sylvie van der Werf 5, 6 Thierry Prazuck 14 Olivier Schwartz 1, 2, *
Abstract : Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.7 and B.1.351 variants were first identified in the United Kingdom and South Africa, respectively, and have since spread to many countries. These variants harboring diverse mutations in the gene encoding the spike protein raise important concerns about their immune evasion potential. Here, we isolated infectious B.1.1.7 and B.1.351 strains from acutely infected individuals. We examined sensitivity of the two variants to SARS-CoV-2 antibodies present in sera and nasal swabs from individuals infected with previously circulating strains or who were recently vaccinated, in comparison with a D614G reference virus. We utilized a new rapid neutralization assay, based on reporter cells that become positive for GFP after overnight infection. Sera from 58 convalescent individuals collected up to 9 months after symptoms, similarly neutralized B.1.1.7 and D614G. In contrast, after 9 months, convalescent sera had a mean sixfold reduction in neutralizing titers, and 40% of the samples lacked any activity against B.1.351. Sera from 19 individuals vaccinated twice with Pfizer Cominarty, longitudinally tested up to 6 weeks after vaccination, were similarly potent against B.1.1.7 but less efficacious against B.1.351, when compared to D614G. Neutralizing titers increased after the second vaccine dose, but remained 14-fold lower against B.1.351. In contrast, sera from convalescent or vaccinated individuals similarly bound the three spike proteins in a flow cytometry-based serological assay. Neutralizing antibodies were rarely detected in nasal swabs from vaccinees. Thus, faster-spreading SARS-CoV-2 variants acquired a partial resistance to neutralizing antibodies generated by natural infection or vaccination, which was most frequently detected in individuals with low antibody levels. Our results indicate that B1.351, but not B.1.1.7, may increase the risk of infection in immunized individuals.
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Contributor : Flora Donati <>
Submitted on : Monday, April 26, 2021 - 11:06:43 AM
Last modification on : Thursday, June 17, 2021 - 6:36:02 PM

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Delphine Planas, Timothée Bruel, Ludivine Grzelak, Florence Guivel-Benhassine, Isabelle Staropoli, et al.. Sensitivity of infectious SARS-CoV-2 B.1.1.7 and B.1.351 variants to neutralizing antibodies. Nature Medicine, Nature Publishing Group, 2021, ⟨10.1038/s41591-021-01318-5⟩. ⟨pasteur-03207907⟩



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