Reactive nitrogen species contribute to innate host defense against Campylobacter jejuni.
Campylobacter jejuni, a gram-negative, invasive organism, is a common cause of food-borne bacterial diarrheal disease. However, the relationship between C. jejuni and the innate immune system is not well described. To better characterize host defense against C. jejuni, we investigated the ability of nitric oxide/reactive nitrogen species to kill two strains of C. jejuni. C. jejuni viability was measured after exposure to reactive nitrogen species produced biochemically as acidified nitrite and by bone marrow-derived macrophages. We report that acidified nitrite caused a 3-log-increased kill of C. jejuni (P < 0.05) at doses that did not affect the viability of Salmonella enterica serovar Typhimurium. Expression of NOS2, the gene responsible for the production of inducible nitric oxide, was increased >100-fold in murine macrophages after incubation with C. jejuni (P < 0.001). These macrophages effected a 2-log-increased kill of C. jejuni over 24 h compared to that by NOS2-/- macrophages unable to produce nitric oxide (P < 0.05). These findings suggest that the mammalian host upregulates the production of nitric oxide in response to exposure to C. jejuni and that nitric oxide and reactive nitrogen species comprise part of the innate defense mechanisms that contribute to the resolution of C. jejuni infection.
Iovine
Nicole M
NM
Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 100161, USA. iovinn01@med.nyu.edu
Pursnani
Seema
S
Voldman
Alex
A
Wasserman
Gregory
G
Blaser
Martin J
MJ
Weinrauch
Yvette
Y
D000818:Animals; D016123:Campylobacter jejuni / Q000276:immunology*; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D015870:Gene Expression; D007113:Immunity, Innate; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D050296:Microbial Viability; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000172:deficiency; D026361:Reactive Nitrogen Species / Q000276:immunology*; D012486:Salmonella typhimurium / Q000276:immunology
D026361:Reactive Nitrogen Species; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse