Intranasal exposure to Stachybotrys chartarum enhances airway inflammation in allergic mice.
BACKGROUND
Exposure to building dampness, often associated with growth of microbes such as Stachybotrys chartarum, has been linked to respiratory symptoms. We have shown previously in a murine model that exposure to S. chartarum can induce lung inflammation characterized by infiltration of neutrophils and lymphocytes; this process is regulated by proinflammatory cytokines and leucocyte-attracting chemokines.


OBJECTIVE
Because an atopic predisposition may influence the response to microbes, we examined the effects of S. chartarum on allergic mice in an experimental model. BALB/c mice were sensitized to ovalbumin by intraperitoneal injections and exposed for 3 wk to spores of S. chartarum.


RESULTS
Numbers of eosinophils and neutrophils were drastically increased in bronchoalveolar fluid from these mice as compared with the ovalbumin-sensitized/challenged mice or those exposed to S. chartarum without ovalbumin sensitization. Histologic sections showed severe granulomatous inflammatory cell infiltrates in all compartments of the lung, including peribronchial, perivascular, and alveolar spaces. The mRNA levels of proinflammatory cytokines interleukin-1beta and tumor necrosis factor alpha and the chemokine CCL3/MIP-1alpha were also markedly increased in the lungs. Despite the enhancement of the pulmonary inflammatory reaction, exposure to S. chartarum spores significantly down-regulated airway hyperresponsiveness and showed a tendency to decrease levels of Th2 cytokines in the lung.


CONCLUSIONS
Exposure to S. chartarum modulates the inflammatory reaction and airway hyperresponsiveness, depending on the allergic status of the exposed mice.
Leino
Marina S
MS
Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FIN-00250, Helsinki, Finland. marina.leino@ttl.fi
Alenius
Harri T
HT
Fyhrquist-Vanni
Nanna
N
Wolff
Henrik J
HJ
Reijula
Kari E
KE
Hintikka
Eeva-Liisa
EL
Salkinoja-Salonen
Mirja S
MS
Haahtela
Tari
T
Mäkelä
Mika J
MJ
D000818:Animals; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006967:Hypersensitivity / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009666:Nose; D011014:Pneumonia / Q000276:immunology* / Q000382:microbiology*; D013191:Stachybotrys / Q000276:immunology*