AIRWAY INFLAMMATION-INDUCED BY RECOMBINANT GUINEA-PIG TUMOR-NECROSIS-FACTOR-ALPHA

We have cloned and expressed recombinant guinea pig tumor necrosis fac tor-alpha (gpTNF-alpha) 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-alpha protein, wa s cloned from concanavalin A-stimulated guinea pig splenocytes. The 15 4-amino acid protein corresponding to secreted gpTNF-alpha was express ed as a fusion protein in Escherichia coli, purified by affinity chrom atography, and cleaved to yield a 17-kDa protein. gpTNF-alpha had a cy totoxic effect on WEHI 164 cells and was detected by goat anti-murine tumor necrosis factor-alpha (TNF-alpha) antibody in Western blots. Int ratracheal instillation of gpTNF-alpha (50-150 ng) caused pronounced a nd dose-dependent airway eosinophilia. Incubation of gpTNF-alpha with rabbit anti-murine TNF-alpha sera or heating the gpTNF-alpha before in stillation reduced bronchoalveolar lavage (BAL) eosinophils to near co ntrol levels. Maximum BAL eosinophilia was observed at 24 h, but eosin ophil numbers remained significantly above vehicle-treated animals for 72 h. Hence, gpTNF-alpha elicits a pronounced and protracted eosinoph il accumulation in the guinea pig lung.