FIGURE 1.

Super low dose LPS primes, whereas high dose LPS tolerizes, the expression of proinflammatory mediators in macrophages. A, WT BMDM were treated either a single dose of LPS (0, 5 pg/ml, 10 ng/ml, or 100 ng/ml) for 4 h or were treated with a second dose of 100 ng/ml LPS for 4 h after the first LPS treatment (0, 5 pg/ml, 10 ng/ml) for 4 h. The cells were washed twice with PBS before the second treatment. The relative transcript levels were standardized against GAPDH levels. B, culture supernatants from primed cells as indicated on the figure legend were used to measure the protein levels of IL-6 (n = 3); mean ± S.D.; *, p < 0.05.