COVID-19 vaccine candidates based on modified vaccinia virus Ankara expressing the SARS-CoV-2 spike induce robust T- and B-cell immune responses and full efficacy in mice.

ABSTRACT: Vaccines against SARS-CoV-2, the causative agent of the COVID-19 pandemic, are urgently needed. We developed two COVID-19 vaccines based on modified vaccinia virus Ankara (MVA) vectors expressing the entire SARS-CoV-2 spike (S) protein (MVA-CoV2-S); their immunogenicity was evaluated in mice using DNA/MVA or MVA/MVA prime/boost immunizations. Both vaccines induced robust, broad and polyfunctional S-specific CD4+ (mainly Th1) and CD8+ T-cell responses, with a T effector memory phenotype. DNA/MVA immunizations elicited higher T-cell responses. All vaccine regimens triggered high titers of IgG antibodies specific for the S, as well as for the receptor-binding domain; the predominance of the IgG2c isotype was indicative of Th1 immunity. Notably, serum samples from vaccinated mice neutralized S

SUBMITTER: Garcia-Arriaza J 

PROVIDER: S-EPMC8092708 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature