Grain dust induces IL-8 production from bronchial epithelial cells: effect on neutrophil recruitment.
BACKGROUND
There have been several investigations suggesting an involvement of activated neutrophils in the development of grain dust (GD)-induced occupational asthma. Interleukin-8 in the sputa from GD-induced asthmatic patients increased significantly after the exposure to GD.


OBJECTIVE
To confirm IL-8 production from bronchial epithelial cells when exposed to GD, and to evaluate the role of IL-8 on neutrophil recruitment.


METHODS
We cultured Beas-2B, a bronchial epithelial cell line. To observe GD-induced responses, four different concentrations ranging from 1 to 200 microg/mL of GD were incubated for 24 hours and compared with those without incubation of GD. To evaluate the effect of pro-inflammatory cytokines on IL-8 production and neutrophil chemotaxis, epithelial cells were incubated with peripheral blood mononuclear cell (PBMC) culture supernatant derived from subjects with GD-induced asthma exposed to 10 microg/mL of GD, and then compared with those without addition of PBMC supernatant. The level of released IL-8 in the supernatant was measured by enzyme-linked immunosorbent assay. Neutrophil chemotactic activity of the culture supernatant was determined by modified Boyden chamber method.


RESULTS
Interleukin-8 production and neutrophil chemotactic activity from bronchial epithelial cells significantly increased with additions of GD in a dose-dependent manner (P < .05, respectively), and were significantly augmented with additions of PBMC supernatant (P < .05, respectively) at each concentration. Close correlation was noted between neutrophil chemotactic activity and IL-8 level (r = 0.87, P < .05). Compared with the untreated sample, pre-treatment of anti-IL-8 antibody induced a significant suppression (up to 67.2%) of neutrophil chemotactic activity in a dose-dependent manner.


CONCLUSIONS
These results suggest that IL-8 produced from bronchial epithelial cells may be a major cytokine, which induces neutrophil migration into the airways when exposed to GD.
Park
H S
HS
Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
Suh
J H
JH
Kim
S S
SS
Kwon
O J
OJ
D000906:Antibodies / Q000494:pharmacology; D001980:Bronchi / Q000166:cytology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology; D004391:Dust; D002523:Edible Grain; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D009504:Neutrophils / Q000166:cytology / Q000502:physiology
D000906:Antibodies; D004391:Dust; D016209:Interleukin-8