Role of Neuraminidase A of S. pneumoniae on platelet-bacteria-interaction

Introduction Streptococcus pneumoniae as an opportunistic human pathogen is a major causative agent of severe community-acquired pneumonia. Pneumococci express pneumolysin (Ply), a cholesterol dependent cytolysin, which forms pores in membranes of eukaryotic cells including platelets. We have shown that pore formation results in diminished platelet function, representing a new pathomechanism during pneumococcal pneumonia. Furthermore, we demonstrated efficient neutralization of Ply with pharmaceutical human IgG (IVIG, Privigen). Besides Ply, S. pneumoniae expresses neuraminidase A (NanA), an enzyme that cleaves specifically sialic acid residues from eukaryotic glycoproteins. This increases binding of Ply to desialylated surface-associated platelet glycoproteins. Here, we aim to decipher how NanA activity affects platelet damage caused by Ply expressing and Ply-deficient strains and the inhibition of these effects by IVIG.