Figure 1.

Pretreatment with exogenous TNF-α attenuates the endogenous TNF-α response to lipopolysaccharide.

Notes: exogenous TNF-α induces production of endogenous TNF-α in a dose-dependent manner (A). In cells pretreated with various concentrations of TNF-α, the subsequent production of TNF-α protein in response to lipopolysaccharide is attenuated in a dose-dependent manner (B). Data are representative of the mean ± standard deviation of two independent experiments analyzed in triplicate. Statistically significant compared with no TNF-α pretreatment control (*P<0.05, student’s t-test).

Abbreviation: TNF-α, tumor necrosis factor-alpha.