Naturally-occurring serotype 3 Streptococcus pneumoniae strains that lack functional pneumolysin and autolysin have attenuated virulence but induce localized protective immune responses.

ABSTRACT: Streptococcus pneumoniae is an important cause of fatal pneumonia in humans. These bacteria express virulence factors, such as the toxins pneumolysin and autolysin, that drive host inflammatory responses. In this study we confirm loss of pneumolysin and autolysin function in a group of clonal pneumococci that have a chromosomal deletion resulting in a pneumolysin-autolysin fusion gene Δ(lytA'-ply')593. The Δ(lytA'-ply')593 pneumococci strains naturally occur in horses and infection is associated with mild clinical signs. Here we use immortalized and primary macrophage in vitro models, which include pattern recognition receptor knock-out cells, and a murine acute pneumonia model to show that a Δ(lytA'-ply')593 strain induces cytokine production by cultured macrophages, however, unlike the s

SUBMITTER: Wong ΗE 

PROVIDER: S-EPMC10004606 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature