FIG. 4.

(A) IL-10 production induced by OspA in PBMC from healthy human donors. PBMC (3 × 10⁶/ml) from each of three donors were incubated with supplemented medium (RPMI), L-OspA or U-OspA (1 μg/ml), heat-killed JD1 (10⁷ spirochetes/ml), LPS (1 μg/ml), or PHA (10 μg/ml) for 48 h. Each pair of bars (open and solid, light and dark hatched, and light and dark stippled) corresponds to one donor. Samples were incubated without (open, light-hatched, and light-stippled bars) or with (solid, dark-hatched, and dark-stippled bars) polymyxin B (50 μg/ml). IL-10 in the supernatant was determined by ELISA. Values are means of duplicate determinations. (B) IL-10 mRNA expression induced by OspA in PBMC from uninfected rhesus monkeys. PBMC (3 × 10⁶/ml) from uninfected rhesus monkeys were stimulated with L-OspA (1 μg/ml), U-OspA (1 μg/ml), or ConA (8 μg/ml) for 24 h. The induced mRNA levels of IL-10 were determined by RT-PCR. Responses are shown as fold increases over unstimulated PBMC. Each point represents the response of PBMC from an individual monkey, and the horizontal lines indicate geometric means. All values were normalized with respect to GAPDH mRNA levels.