Direct and indirect bacterial killing functions of neutrophil defensins in lung explants.
Am J Physiol Lung Cell Mol Physiol
; 281(5): L1240-7, 2001 Nov.
Article
en En
| MEDLINE
| ID: mdl-11597916
Studies of the antimicrobial activity of neutrophil defensins have mostly been carried out in microbiological media, and their effects on the host defense in physiological conditions are unclear. We examined 1) the antibacterial activity of defensins in physiological media with and without lung tissue present, 2) the effect of defensins on hydrogen peroxide (H(2)O(2)) production by lung tissue that had been exposed to bacteria, and 3) the effect of diphenyleneiodonium (DPI), an inhibitor of reactive oxygen species formation, on the antibacterial activity of defensins in the presence of lung tissue. Defensins were incubated with Escherichia coli or Pseudomonas aeruginosa in the absence or presence of primary cultured mouse lung explants. Defensins reduced bacterial counts by approximately 65-fold and approximately 25-fold, respectively, at 48 h; bacterial counts were further decreased by approximately 600-fold and approximately 12,000-fold, respectively, in the presence of lung tissue. Defensins induced H(2)O(2) production by lung tissue, and the rate of killing of E. coli by defensins was reduced by approximately 2,500-fold in the presence of 10 microM DPI. We conclude that defensins exert a significant antimicrobial effect under physiological conditions and that this effect is enhanced in the presence of lung tissue by a mechanism that involves the production of reactive oxygen species.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Defensinas
/
Pulmón
/
Neutrófilos
Límite:
Animals
/
Humans
/
Male
Idioma:
En
Revista:
Am J Physiol Lung Cell Mol Physiol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Año:
2001
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Estados Unidos