Transfer of anti-Klebsiella pneumoniae immunity following infection in mice is protective against lethal challenge in offspring.

Klebsiella pneumoniae is a gram-negative, opportunistic pathogen, with high rates of antimicrobial resistance, and is responsible for a wide range of infections of the urinary tract, lungs, and bloodstream, among others. Disease burden is particularly high in neonates, where K. pneumoniae is a leading cause of sepsis. Renewed interest in vaccine development against this critical priority pathogen has focused on this vulnerable population. Vaccination in pregnancy is a promising approach for prevention of neonatal sepsis, however efforts to understand the dynamics, specificity and function of maternally transferred antibodies is ongoing. We report here that K. pneumoniae-specific IgG is readily transferred from dam to pup following wild-type infection in mice, and that maternally-transferred immunity is protective against lethal infection in pups aged 6 weeks. Further work to investigate the mechanisms of protection and explore neonatal challenge models will advance the path to a maternal vaccine to protect against neonatal sepsis.