TITLE:
Oral Lactobacillus plantarum NCIMB 8825 Inhibits Adhesion, Invasion and Metabolism of Neisseria meningitidis Serogroup B and Affords Anti-Inflammatory and Cytotoxic Protection to Nasopharyngeal Epithelial Cells
AUTHORS:
Tezera Liku Bekele, Page Keith, Rhakimova Adelina, Salisbury Vyvyan, Davenport Victoria
KEYWORDS:
Epithelial; Protection; Neisseria meningitides; Lactobacillus; Innate; Lux
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.2,
January
21,
2014
ABSTRACT:
In this study, we investigate the potential for oral
Lactobacilli (LB) to afford innate protection against nasopharyngeal coloniser Neisseria
meningitidis serogroup B (NmB), which causes the bulk of UK meningococcal
disease. Oral isolates of L. plantarum, L. salivarious, L. casei, L. rhamnosus, L.
gasseri and gut probiotic L. rhamnosus GG were assessed for
their ability to suppress nasopharyngeal epithelial inflammatory responses to
pathogenic NmB. The specificity of attenuation was examined using TLR 2 ligand,
Pam3Cys, and early response cytokine IL1β;
and the mechanism of attenuation was explored using heat-killed organisms and
conditioned medium. Pro-inflammatory IL-6 and TNFα cytokine secretion was quantified by ELISA and associated cell
death was quantified by PI staining and LDH release. NmB adhesion, invasion and
metabolism were determined using standard gentamicin protection with viable
counts, and bioluminescence, respectively. L. plantarum and L.
salivarious suppressed IL-6 and TNFα secretions from NmB-infected epithelial cells. LB did not need to be alive and
could suppress using secretions, which were independent of TLR2 or IL1β receptor signalling. L. plantarum,
in particular, reduced NmB-induced necrotic cell death of epithelial
monolayers. Like L. salivarious, it significantly
inhibited NmB adhesion but uniquely L. plantarum abolished NmB invasion.
Using bioluminescence as a reporter of pathogen metabolism, L. plantarum and its secretions were found to inhibit NmB metabolism during cell invasion assays.
We conclude that oral L. plantarum and its secretions could be used to
help reduce the burden of meningococcal disease by removing the intracellular
nasopharyngeal reservoir of NmB.