Comparison of the inflammatory responses of human meningeal cells following challenge with Neisseria lactamica and with Neisseria meningitidis

Mark I. Fowler, Kiave Y. Ho Wang Yin, Holly E. Humphries, John E. Heckels, Myron Christodoulides*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The rationale for the present study was to determine how different species of bacteria interact with cells of the human meninges in order to gain information that would have broad relevance to understanding aspects of the innate immune response in the brain. Neisseria lactamica is an occasional cause of meningitis in humans, and in this study we investigated the in vitro interactions between N. lactamica and cells derived from the leptomeninges in comparison with the closely related organism Neisseria meningitidis, a major cause of meningitis worldwide. N. lactamica adhered specifically to meningioma cells, but the levels of adherence were generally lower than those with N. meningitidis. Meningioma cells challenged with N. lactamica and N. meningitidis secreted significant amounts of the proinflammatory cytokine interleukin-6 (IL-6), the C-X-C chemokine IL-8, and the C-C chemokines monocyte chemoattractant protein 1 (MCP-1) and RANTES, but it secreted very low levels of the cytokine growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF). Thus, meningeal cells are involved in the innate host response to Neisseria species that are capable of entering the cerebrospinal fluid. The levels of IL-8 and MCP-1 secretion induced by both bacteria were essentially similar. By contrast, N. lactamica induced significantly lower levels of IL-6 than N. meningitidis. Challenge with the highest concentration of N. lactamica (108 CFU) induced a small but significant down-regulation of RANTES secretion, which was not observed with lower concentrations of bacteria. N. meningitidis (106 to 108 CFU) also down-regulated RANTES secretion, but this effect was significantly greater than that observed with N. lactamica. Although both bacteria were unable to invade meningeal cells directly, host cells remained viable on prolonged challenge with N. lactamica, whereas N. meningitidis induced death; the mechanism was overwhelming necrosis with no significant apoptosis. It is likely that differential expression of modulins between N. lactamica and N. meningitidis contributes to these observed differences in pathogenic potential.

Original languageEnglish
Pages (from-to)6467-6478
Number of pages12
JournalInfection and Immunity
Volume74
Issue number11
DOIs
Publication statusPublished - Nov 2006
Externally publishedYes

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