Figure 4

PPC enhances the production of IFNγ ⁺ /CD8 ⁺ T cells in response to a protein vaccine. C57BL/6 mice (4/group) were injected s.c. on day 0 and day 14 with 500 μg OVA formulated in IFA. CPG (100 μg) or poly I:C (50 μg) was included in the priming and booster injections to serve as positive controls. Other mice were provided PPC (20, 200, or 2000 μg/mL) in their drinking water beginning on day 7 and lasting until day 21 when the IFNγ ELISPOT analysis was performed. The number of spots (CD8^+/IFNγ⁺ cells per 10⁵ isolated CD8⁺ cells) is shown. Error bars represent the standard deviation. The (*) represents a p < 0.006, while the (**) represents a p < 0.001.