EFFECT OF TUMOR-NECROSIS-FACTOR RECEPTOR-BINDING PROTEIN ON CELL INFILTRATION INDUCED BY LIPOPOLYSACCHARIDE AND SEPHADEX BEADS IN GUINEA-PIG LUNG

In the present study, the effect of a tumor necrosis factor receptor b inding protein (TNFbp) on the cell infiltration induced by lipopolysac charide (LPS) and Sephadex beads in guinea pig lung was examined. The intratracheal injection of LPS (2.5 mu g) induced a six-fold increase in total cell number recovered in bronchoalveolar lavage (BAL) fluid a t 24 hr. This increase in bronchopulmonary inflammation was mainly due to a neutrophil and macrophage infiltration, representing 60% and 35% of the total cells, respectively. The intravenous or intratracheal in jection of Sephadex beads to guinea pigs induced a three-fold increase in total cell number recovered in BAL at 24 h and was characterized b y a prominent eosinophil, macrophage, and neutrophil infiltration repr esenting 36%, 42%, and 16% of the total cells, respectively. In additi on, bronchial tissues isolated from Sephadex-treated guinea pigs showe d an increased in vitro reactivity to both histamine and acetylcholine . TNFbp (1-50 mu g) induced a dose-dependent inhibition of cell infilt ration induced by LPS. In contrast TNFbp neither attenuated the bronch opulmonary cell infiltration observed 24 h following intravenous or in tratracheal administration of Sephadex beads nor inhibited the increas e in bronchial reactivity. These results show that TNF plays an import ant role in cell infiltration induced by LPS, but not that induced by Sephadex, in the guinea pig lung.