INDUCTION OF IL-8 PRODUCTION IN HUMAN ALVEOLAR MACROPHAGES AND HUMAN BRONCHIAL EPITHELIAL-CELLS IN-VITRO BY SWINE DUST

Background-Exposure to swine dust causes an intense airway inflammatio n with increased levels of interleukin 8 (IL-8) and predominantly neut rophils in the nasal and bronchoalveolar lavage fluids of healthy huma n subjects. It is not clear which components in the swine house enviro nment are responsible for the airway reaction. The aim of the present study was to evaluate and compare the effect in vitro of swine dust co mponents on human alveolar macrophages and bronchial epithelial cells. Methods-Normal human bronchial epithelial cells (NHBE), human pulmona ry epithelial carcinoma cell Line (A549), and human alveolar macrophag es were stimulated with swine dust, lipopolysaccharides (LIPS; present : in Gram negative bacteria), grain dust (swine feed components), and glucans (a structural component of fungi) in a dose response manner (1 -100 mu g/ml). Results-Swine dust at a concentration of 100 mu g/ml in creased IL-8 production 20 fold in NHBE cells, 28 fold in A549 cells, and 15 fold in macrophages. LPS (100 mu g/ml) stimulated all three cel l types significantly, in macrophages to the same extent as swine dust , but in NHBE and A549 cells swine dust was 5-8 times as potent. Grain dust (100 mu g/ml) had no effect in A549 cells but stimulated NHBE ce lls and macrophages. Glucans (100 mu g/ ml) stimulated A549 cells and macrophages but not NHBE cells. Both glucans and grain dust were weake r stimuli than swine dust and LPS. The LPS content of swine dust solut ion was 2.16 (0.2)ng/ 100 mu g and of grain dust was 0.53 (0.04) ng/10 0 mu g. Conclusions-Swine dust is a strong stimulus for IL-8 productio n in both bronchial epithelial cells and human alveolar macrophages, w hereas LPS has different potency in these cells.