Cross-sectional evaluation of humoral responses against SARS-CoV-2 Spike

Prévost, Jérémie; Gasser, Romain; Beaudoin-Bussières, Guillaume; Richard, Jonathan; Duerr, Ralf; Laumaea, Annemarie; Anand, Sai Priya; Goyette, Guillaume; Benlarbi, Mehdi; Ding, Shilei; Medjahed, Halima; Lewin, Antoine; Perreault, Josée; Tremblay, Tony; Gendron-Lepage, Gabrielle; Gauthier, Nicolas; Carrier, Marc; Marcoux, Diane; Piché, Alain; Lavoie, Myriam; Benoit, Alexandre; Loungnarath, Vilayvong; Brochu, Gino; Haddad, Elie; Stacey, Hannah D.; Miller, Matthew S.; Desforges, Marc; Talbot, Pierre J.; Gould Maule, Graham T.; Côté, Marceline; Therrien, Christian; Serhir, Bouchra; Bazin, Renée; Roger, Michel; Finzi, Andrés

The SARS-CoV-2 virus is responsible for the coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The Spike glycoproteins of SARS-CoV-2 mediates viral entry and is the main target for neutralizing antibodies. Understanding the antibody response directed against SARS-CoV-2 is crucial for the development of vaccine, therapeutic and public health interventions. Here we perform a cross-sectional study on 106 different SARS-CoV-2-infected individuals to evaluate humoral responses against SARS-CoV-2 Spike. The vast majority of infected individuals elicits anti-Spike antibodies within 2 weeks after the onset of symptoms. The levels of receptor-binding domain (RBD)-specific IgG persist overtime, while the levels of anti-RBD IgM decrease after symptoms resolution. While most of individuals develop neutralizing antibodies within two weeks of infection, the level of neutralizing activity is significantly decreased over time. Our results highlight the importance of studying the persistence of neutralizing activity upon natural SARS-CoV-2 infection.