SARS-CoV-2 RBD-Tetanus Toxoid Conjugate Vaccine Induces a Strong Neutralizing Immunity in Preclinical Studies
Yury Valdés-Balbín, Darielys Santana-Mederos, Lauren Quintero, Sonsire Fernández-Castillo, Laura Rodríguez, Belinda Sánchez Ramírez, Rocmira Pérez-Nicado, Claudia Acosta, Yanira Méndez, Manuel G. Ricardo, Tays Hernández, Gretchen Bergado, Franciscary Pi, Annet Valdes, Tania Carmenate, Ubel Ramírez, Reinaldo Oliva, Jean-Pierre Soubal, Raine Garrido, Félix Cardoso, Mario Landys, Humberto González Galbán, Mildrey Fariñas, Juliet Enriquez, Enrique Noa, A. Galvez Suarez, Fang Cheng, Luis Ariel Espinosa, Yassel Ramos, Luis Javier González, Yanet Climent, Gertrudis Rojas, Ernesto Relova-Hernández, Yanelys Cabrera Infante, Sum Lai Losada, Tammy Boggiano-Ayo, Eduardo Ojito, Kalet León, Fabrizio Chiodo, Françoise Paquet, Guang‐Wu Chen, Daniel G. Rivera, Dagmar García-Rivera, Vicente Vérez-Bencomo
Abstract
Controlling the global COVID-19 pandemic depends, among other measures, on developing preventive vaccines at an unprecedented pace. Vaccines approved for use and those in development intend to elicit neutralizing antibodies to block viral sites binding to the host's cellular receptors. Virus infection is mediated by the spike glycoprotein trimer on the virion surface via its receptor binding domain (RBD). Antibody response to this domain is an important outcome of immunization and correlates well with viral neutralization. Here, we show that macromolecular constructs with recombinant RBD conjugated to tetanus toxoid (TT) induce a potent immune response in laboratory animals. Some advantages of immunization with RBD-TT conjugates include a predominant IgG immune response due to affinity maturation and long-term specific B-memory cells. These result demonstrate the potential of the conjugate COVID-19 vaccine candidates and enable their advance to clinical evaluation under the name SOBERANA02, paving the way for other antiviral conjugate vaccines.