The Bacterial Mucosal Immunotherapy MV130 Protects Against SARS-CoV-2 Infection and Improves COVID-19 Vaccines Immunogenicity
Carlos del Fresno, Juan García‐Arriaza, Sarai Martínez-Cano, Ignacio Heras‐Murillo, Aitor Jarit-Cabanillas, J. Amores, Paola Brandi, Gillian Dunphy, Carmen Suay‐Corredera, María Rosaria Pricolo, Natália Vicente, Andrés López‐Perrote, Sofía Cabezudo, Ana González‐Corpas, Óscar Llorca, Jorge Alegre‐Cebollada, Urtzi Garaigorta, Pablo Gastaminza, Mariano Estéban, David Sancho
Abstract
COVID-19-specific vaccines are efficient prophylactic weapons against SARS-CoV-2 virus. However, boosting innate responses may represent an innovative way to immediately fight future emerging viral infections or boost vaccines. MV130 is a mucosal immunotherapy, based on a mixture of whole heat-inactivated bacteria, that has shown clinical efficacy against recurrent viral respiratory infections. Herein, we show that the prophylactic intranasal administration of this immunotherapy confers heterologous protection against SARS-CoV-2 infection in susceptible K18-hACE2 mice. Furthermore, in C57BL/6 mice, prophylactic administration of MV130 improves the immunogenicity of two different COVID-19 vaccine formulations targeting the SARS-CoV-2 spike (S) protein, inoculated either intramuscularly or intranasally. Independently of the vaccine candidate and vaccination route used, intranasal prophylaxis with MV130 boosted S-specific responses, including CD8 + -T cell activation and the production of S-specific mucosal IgA antibodies. Therefore, the bacterial mucosal immunotherapy MV130 protects against SARS-CoV-2 infection and improves COVID-19 vaccines immunogenicity.