Adjuvant effect of respiratory irritation on pulmonary allergic sensitization: time and site dependency.
Siegel-PD; Humadi-NH-Al; Nelson-ER; Lewis-DM; Hubbs-AF
Toxicol Appl Pharmacol 1997 Jun; 144(2):356-362
The effect of site and time of exposure of acute irritation of the respiratory tract on pulmonary allergic sensitization was examined. Site selective irritation was produced in male Brown-Norway-rats in the upper respiratory tract with ammonia (7664417) and in the lower respiratory tract with nitrogen-dioxide (10102440) (NO2). Irritant exposures lasted one hour. Six weekly 30 minute antigen exposures with ovalbumin (OVA) were administered. At three weeks, circulating antigen specific immunoglobulin-E (IgE) was about ten times higher in rats in which the sensitizing exposure was present during the pulmonary NO2 response. Enhanced immunoglobulin-G (IgG) and immunoglobulin-A (IgA) production to NO2 induced lower lung irritation occurred at 6 weeks. A significant attenuation of eosinophil inflammation occurred in the rats receiving the initial sensitizing OVA exposure 7 days after acute NO2 inhalation. Acute exposure to ammonia did not significantly alter the OVA IgG, IgE, or IgA profiles during the six week period. The same trend occurred in OVA only treated rats. The authors conclude that the pulmonary sensitizing response may be influenced by the area of the respiratory tract affected, with lower lung irritants being more potent adjuvants.
Laboratory-animals; Allergic-reactions; Respiratory-irritants; Bronchial-asthma; Lung-irritants; Environmental-pollution; Nitrogen-dioxides; Immunoglobulins
Toxicology and Applied Pharmacology