Dosage and Timing of Anti-TNF-α Antibody Treatment Determine Its Effect on Resistance to Sepsis after Injury

Abstract Antibody against tumor necrosis factor-α (TNF-α) has improved survival in certain models of sepsis, but it remains unproven in clinical studies. In most of the successful animal studies, efficacy has been shown in previously healthy animals subjected to a septic challenge. Patients at risk for sepsis, however, may be ill for some time before the sepsis supervenes. This situation has been described as a “two-hit” model of critical illness. We have developed an animal burn–sepsis model which conforms to this “two-hit” concept. We have quantified macrophage TNF-α production at different times after the burn (first “hit”) and determined the effect of neutralizing antibody against TNF-α during this period on survival after subsequent sepsis (second “hit”). The objective of this study was to determine the role of TNF-α and the effect of neutralizing antibody against TNF-α in a burn–sepsis model. Animals were subjected to a full thickness burn or sham burn.In vitroTNF-α production from cultured lipopolysaccharide-stimulated splenic adherent cells was determined at various time points thereafter by enzyme-linked immunosorbent assay. Separate animals were treated with neutralizing antibody against TNF-α at different time points after the thermal injury, and survival was determined after septic challenge (cecal ligation and puncture) on Day 10 after the burn. TNF-α production from adherent splenocytes was not elevated in the early days after thermal injury, but was significantly enhanced from Day 6 onward compared with sham-burned animals. Nine percent of the burned mice survived septic challenge compared with 69% of the sham-burned control mice (P