Mucosal Vaccination Against SARS-CoV-2 Using Human Probiotic <i>Bacillus subtilis</i> Spores as an Adjuvant Induces Potent Systemic and Mucosal Immunity.

ABSTRACT: Background/Objectives: The ongoing evolution of SARS-CoV-2 has highlighted the limitations of parenteral vaccines in preventing viral transmission, largely due to their failure to elicit robust mucosal immunity. Methods: Here, we evaluated an intranasal (IN) vaccine formulation consisting of recombinant receptor-binding domain (RBD) adsorbed onto human probiotic Bacillus subtilis DG101 spores. Results: In BALB/c mice, IN spore-RBD immunization induced strong systemic and mucosal humoral responses, including elevated specific IgG, IgM, and IgA levels in serum, bronchoalveolar lavage fluid (BALF), nasal-associated lymphoid tissue (NALT), and saliva. It further promoted mucosal B cell and T cell memory, along with a Th1/Tc1-skewed T cell response, characterized by

SUBMITTER: Ramos Pupo R 

PROVIDER: S-EPMC12298100 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature