RESUMO
Developing an effective Staphylococcus aureus (S. aureus) vaccine has been a challenging endeavor, as demonstrated by numerous failed clinical trials over the years. In this study, we formulated a vaccine containing a highly conserved moonlighting protein, the pyruvate dehydrogenase complex E2 subunit (PDHC), and showed that it induced strong protective immunity against epidemiologically relevant staphylococcal strains in various murine disease models. While antibody responses contributed to bacterial control, they were not essential for protective immunity in the bloodstream infection model. Conversely, vaccine-induced systemic immunity relied on γδ T cells. It has been suggested that prior S. aureus exposure may contribute to the reduction of vaccine efficacy. However, PDHC-induced protective immunity still facilitated bacterial clearance in mice previously exposed to S. aureus. Collectively, our findings indicate that PDHC is a promising serotype-independent vaccine candidate effective against both methicillin-sensitive and methicillin-resistant S. aureus isolates.
Assuntos
Infecções Estafilocócicas , Vacinas Antiestafilocócicas , Staphylococcus aureus , Animais , Infecções Estafilocócicas/prevenção & controle , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Camundongos , Staphylococcus aureus/imunologia , Staphylococcus aureus/enzimologia , Vacinas Antiestafilocócicas/imunologia , Complexo Piruvato Desidrogenase/metabolismo , Complexo Piruvato Desidrogenase/imunologia , Feminino , Anticorpos Antibacterianos/imunologia , Modelos Animais de Doenças , Humanos , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Camundongos Endogâmicos C57BL , Staphylococcus aureus Resistente à Meticilina/imunologia , Piruvato Desidrogenase (Lipoamida)/imunologia , Piruvato Desidrogenase (Lipoamida)/metabolismo , Piruvato Desidrogenase (Lipoamida)/genéticaRESUMO
The overall success of worldwide mass vaccination in limiting the negative effect of the COVID-19 pandemics is inevitable, however, recent SARS-CoV-2 variants of concern, especially Omicron and its sub-lineages, efficiently evade humoral immunity mounted upon vaccination or previous infection. Thus, it is an important question whether these variants, or vaccines against them, induce anti-viral cellular immunity. Here we show that the mRNA vaccine BNT162b2 induces robust protective immunity in K18-hACE2 transgenic B-cell deficient (µMT) mice. We further demonstrate that the protection is attributed to cellular immunity depending on robust IFN-γ production. Viral challenge with SARS-CoV-2 Omicron BA.1 and BA.5.2 sub-variants induce boosted cellular responses in vaccinated µMT mice, which highlights the significance of cellular immunity against the ever-emerging SARS-CoV-2 variants evading antibody-mediated immunity. Our work, by providing evidence that BNT162b2 can induce significant protective immunity in mice that are unable to produce antibodies, thus highlights the importance of cellular immunity in the protection against SARS-CoV-2.