Figure 2

Suppressed induction of an IgE response. Mice were injected s.c. on day 0 and day 14 with 100 μg OVA (left panel) or 500 μg OVA formulated in IFA (right panel). CpG (100 μg s.c.) or poly I:C (50 μg s.c.) were delivered at the time of priming and booster injections to serve as positive controls. Mice in the left panel received 2, 20, or 200 μg PPC by gavage at the time of the priming and booster injections, or 200 μg/mL PPC in the drinking water ad libitum, beginning at the time of the priming injection. Mice in the right panel were provided PPC (20, 200, or 2000 μg/mL) ad libitum in their drinking water beginning on day -1 and lasting until day 21 when the total serum IgE ELISA assays were performed. All mice receiving PPC also received the OVA vaccine. Error bars represent the standard deviation. The (**) represents a p < 0.001 and (***) represents a p < 0.0001.