Anti-tumor effect elicited by immunization with γ-PGA NP/OVA. C57BL/6 mice were immunized subcutaneously with γ-PGA NP/OVA (●; 100 μg OVA, ○; 10 μg OVA), CFA/OVA (□ 100 μg OVA), OVA solution (◆; 100 μg OVA), or PBS (△). Ten days later, 106 E.G7-OVA cells were inoculated intradermally into the flank of each mouse; then the tumor volume was monitored. Each point represents the mean ± S.E. from 5 to 9 mice. Statistical significance of γ-PGA NP/OVA (100 μg OVA) vs. CFA/OVA on day 18 was determined by Student’s t-test (*P < 0.05). Reprinted with permission from (156) © Elsevier Inc. (2008).