Airway inflammation induced by recombinant guinea pig tumor necrosis factor-α

We have cloned and expressed recombinant guinea pig tumor necrosis factor-α (gpTNF-α) and examined its inflammatory activities after tracheal instillation in guinea pigs. A 1, 071-bp cDNA, including the region encoding the full-length 234-amino acid gpTNF-α protein, was cloned from concanavalin A-stimulated guinea pig splenocytes. The 154-amino acid protein corresponding to secreted gpTNF-α was expressed as a fusion protein in Escherichia coli, purified by affinity chromatography, and cleaved to yield a 17-kDa protein. gpTNF-α had a cytotoxic effect on WEHI 164 cells and was detected by goat anti-murine tumor necrosis factor-α (TNF-α) antibody in Western blots. Intratracheal instillation of gpTNF-α (50-150 ng) caused pronounced and dose-dependent airway eosinophilia. Incubation of gpTNF-α with rabbit anti-murine TNF-α sera or heating the gpTNF-α before instillation reduced bronchoalveolar lavage (BAL) eosinophils to near control levels. Maximum BAL eosinophilia was observed at 24 h, but eosinophil numbers remained significantly above vehicle-treated animals for 72 h. Hence, gpTNF-a elicits a pronounced and protracted eosinophil accumulation in the guinea pig lung.