Pneumococci stimulate the production of the inducible nitric oxide synthase and nitric oxide by murine macrophages.
The role of nitric oxide (NO) in the pathophysiology of gram-positive sepsis is uncertain. In inflammatory conditions, high-output NO production is catalyzed by the enzyme inducible nitric oxide synthase (iNOS). The ability of 2 strains of pneumococci, pneumococcal cell wall preparations, and purified pneumococcal capsule (Pnu-Imune 23) to trigger the production of iNOS protein and NO in RAW 264.7 murine macrophages was tested. Live pneumococci, oxacillin-killed pneumococci, and pneumococcal cell wall preparations stimulated the production of iNOS and NO by RAW 264.7 cells in the presence, but not the absence, of low concentrations of recombinant murine interferon-gamma. In contrast, purified pneumococcal capsule induced little or no iNOS or NO production by these cells. Thus, pneumococci stimulate high-output NO production by murine macrophages. The potential role of NO in the pathogenesis of pneumococcal sepsis deserves further study.
Orman
K L
KL
Department of Pediatrics, University of Tennessee, Memphis, TN, USA. korman@utmem1.utmem.edu
Shenep
J L
JL
English
B K
BK
D000818:Animals; D016470:Bacteremia; D002460:Cell Line; D002473:Cell Wall; D004790:Enzyme Induction; D007371:Interferon-gamma / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology* / Q000502:physiology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D010068:Oxacillin / Q000494:pharmacology; D011008:Pneumococcal Infections; D011994:Recombinant Proteins; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000502:physiology*
D011994:Recombinant Proteins; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D010068:Oxacillin