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The Protective Role of Bacillus anthracis Exosporium in Macrophage‐Mediated Killing by Nitric Oxide
Author(s) -
Weaver John,
Kang Tae Jin,
Raines Kimberly,
Cao GuanLiang,
Hibbs Stephen,
Tsai Pei,
Rosen Gerald,
Cross Alan,
Baillie Les
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a624
Subject(s) - bacillus anthracis , peroxynitrite , microbiology and biotechnology , macrophage , nitric oxide , bacteria , biology , endospore , chemistry , spore , in vitro , biochemistry , enzyme , genetics , endocrinology , superoxide
The ability of the endospore‐forming, gram‐positive bacterium Bacillus anthracis to survive in activated macrophages is key to its germination and survival. In a previous study, we discovered that upon exposure to primary murine macrophages, B. anthracis endospores up‐regulated NOS 2 concomitant with a ·NO‐dependent bactericidal response. Since NOS 2 also generates O2·−, experiments were designed to determine whether NOS 2 formed peroxynitrite (ONOO‐) from the reaction of ·NO with O2· − and if so, was ONOO‐ microbicidal toward B. anthracis. Our findings suggest that ONOO‐ was formed upon macrophage infection by B. anthracis endospores; however, ONOO‐ does not appear to exhibit microbial activity toward this bacterium. In contrast, the exosporium of B. anthracis, which exhibits arginase activity, protected B. anthracis from macrophage‐mediated killing by decreasing ·NO levels in the macrophage. Thus, the ability of B. anthracis to subvert ·NO production has important implications in the control of B. anthracis‐induced infection.