Eotaxin and nitric oxide production as markers of inflammation in allergic cynomolgus monkeys.
BACKGROUND
Cynomolgus monkeys have a natural hypersensitivity to Ascaris suum antigen. Inhalation of antigen produces immediate and delayed allergic reactions and an influx of inflammatory cells into the lungs. This study investigated the production of nitric oxide (NO) and the chemokine eotaxin during this allergic response. The effect of bronchoscopy alone on lung inflammatory cells was also investigated along with the time course of the eosinophil influx into the lung.


METHODS
Allergic cynomolgus monkeys were challenged with antigen. Bronchoalveolar lavage (BAL) was performed before and after challenge, and end-tidal NO was measured before and 24 h after challenge. Eotaxin was measured in the BAL fluid 6, 24 and 72 h after challenge. One group of animals was treated with dexamethasone before challenge to block the influx of cells into the lung.


RESULTS
BLA alone induced an influx of neutrophils, but not eosinophils, into the lung 24 h later. A single antigen challenge produced a marked increase in BAL eosinophils that was apparent at 6 h but increased at 72 h after challenge. The increase at 6 h was largely blocked by dexamethasone. Three antigen challenges produced elevated BAL eosinophil levels that persisted for at least 8 weeks. Eotaxin levels rose dramatically 6 h after challenge and remained the same after 24 h. By 72 h, the eotaxin levels had returned to baseline. The increase in eotaxin at 6 h was nonsignificantly reduced by dexamethasone. Exhaled NO levels doubled 24 h after challenge and were not affected by dexamethasone.


CONCLUSIONS
Eotaxin and NO production were increased after airway challenge in allergic monkeys. The rise in NO was not blocked by dexamethasone. The effects of bronchoscopy on the BAL can be avoided by using alternate lungs on consecutive occasions. Eosinophils persist in the BAL for many weeks after antigen challenge.
Young
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SS
Schering-Plough Research Institute, Kenilworth, N.J. 07033, USA.
Ritacco
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Skeans
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Chapman
R W
RW
D000818:Animals; D000941:Antigens / Q000378:metabolism; D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D001999:Bronchoscopy / Q000009:adverse effects; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016207:Cytokines / Q000096:biosynthesis*; D003907:Dexamethasone / Q000378:metabolism; D004804:Eosinophils / Q000378:metabolism; D006967:Hypersensitivity / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism*; D008252:Macaca fascicularis / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D013997:Time Factors
D000941:Antigens; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016207:Cytokines; D009569:Nitric Oxide; D003907:Dexamethasone