Abstract
Group B Streptococcus (GBS) and Staphylococcus aureus cause 200.000 neonatal deaths every year and no vaccine has been developed yet. Here, we described that extracellular glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from S. aureus is an immunomodulatory protein. Antibody mediated neutralization of S. aureus extracellular GAPDH promotes a protective inflammatory response by inhibiting an early and abnormal production of IL-10 in infected neonatal mice. As an immunomodulatory role for extracellular GAPDH was already described for GBS, we selected peptides exposed on bacterial GAPDH from both bacteria but completely absent from human GAPDH. These peptides were chemically synthesized and conjugated to a carrier protein. Maternal vaccination with these conjugated peptides induced an increased survival of mouse pups from infection with GBS or S. aureus, when compared to controls. The addition of anti-bacterial GAPDH IgG into infected human cord-blood cells caused a significant reduction in bacterial replication, suggesting a putative efficacy for humans.