The Type II Secretion System of Legionella pneumophila Dampens the MyD88 and Toll-Like Receptor 2 Signaling Pathway in Infected Human Macrophages.

ABSTRACT: Previously, we reported that mutants of Legionella pneumophila lacking a type II secretion (T2S) system elicit higher levels of cytokines (e.g., interleukin-6 [IL-6]) following infection of U937 cells, a human macrophage-like cell line. We now show that this effect of T2S is also manifest upon infection of human THP-1 macrophages and peripheral blood monocytes but does not occur during infection of murine macrophages. Supporting the hypothesis that T2S acts to dampen the triggering of an innate immune response, we observed that the mitogen-activated protein kinase (MAPK) and nuclear transcription factor kappa B (NF-κB) pathways are more highly stimulated upon infection with the T2S mutant than upon infection with the wild type. By using short hairpin RNA to deplete proteins involved in spe

SUBMITTER: Mallama CA 

PROVIDER: S-EPMC5364298 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature