Respiratory immunization using antibiotic-inactivated Bordetella pertussis confers T cell-mediated protection against nasal infection in mice.

The Gram-negative bacterium Bordetella pertussis causes whooping cough (pertussis), a severe respiratory disease, especially in young children, which is resurgent despite high vaccine coverage. The current acellular pertussis vaccine prevents severe disease but does not prevent nasal infection with B. pertussis. This parenterally delivered vaccine induces potent circulating antibody responses but limited respiratory tissue-resident memory T cells and IgA responses. Here we developed a vaccine approach based on respiratory delivery of antibiotic-inactivated B. pertussis (AIBP). Ciprofloxacin-treated B. pertussis potently activated antigen-presenting cells to drive T cell responses. AIBP immunization via aerosol or intranasal administration conferred a high level of protection against lung and nasal infection. The AIBP vaccine induced B. pertussis-specific interleukin (IL)-17-producing CD4 tissue-resident memory T cells that recruited neutrophils to the respiratory tract. Protection was abrogated by depletion of CD4 T cells or neutralization of IL-17 in mice. Unlike a parenterally delivered whole-cell pertussis vaccine, which induced high levels of serum IL-1β, IL-6, tumour necrosis factor and C-reactive protein, aerosol immunization with the AIBP vaccine did not promote systemic pro-inflammatory responses. We present preclinical evidence of a safe and effective respiratory-delivered vaccine platform for inducing T cell-mediated sterilizing immunity against a respiratory pathogen.