Tumor necrosis factor production in cats in response to lipopolysaccharide: an in vivo and in vitro study.

Supernatants from feline peritoneal exudate cells (PECs) exposed to lipopolysaccharde (LPS) produced significantly (P < 0.05) more tumor necrosis factor (TNF) activity than supernatants from cells exposed to media. An in vitro LPS response was obtained following incubation of whole blood with 10 micrograms ml-1 LPS for 2 h. Intravenous infusion of LPS (750 micrograms kg-1 rapidly increased plasma TNF activity to a maximum at 60 min after initiation of LPS infusion. By 180 min, TNF activity returned to baseline. Cats produce TNF in response to LPS in a manner similar to other species. Measurement of TNF activity in plasma or in LPS-stimulated whole blood are methods to further characterize the inflammatory response in feline diseases.