Enhancement of antitumor immunity in mice immunized with Ii AS ODN-treated DCs. Mice were immunized twice weekly with DCs transfected with either OVA or Flu M1 mRNA, or mock-immunized with PBS, treated with either of 2 Ii AS ODNs (AE54 or AE40) or 2 control ODNs (SE46 or SE54), as indicated, and challenged subcutaneously with B16/F10.9-OVA tumor cells 10 days after the second immunization (5 mice per group). (A) Day-21 tumor measurements. There was no statistical difference between the PBS group relative to the Flu M1 RNA mRNA group, among the 3 OVA mRNA groups not treated or treated with either of the 2 control ODNs, and between the 2 OVA mRNA groups treated with either of the 2 Ii AS ODNs. The P values for the PBS group relative to the OVA mRNA + control ODN groups and for the OVA mRNA + control ODN groups relative to the OVA mRNA + Ii AS ODN groups were less than .002. (B) Time to appearance of palpable tumors. Statistical significance was determined using the log-rank test. P values were .0015 for the OVA mRNA + control ODN group relative to the Flu M1 RNA group and .001 for the OVA mRNA + Ii AS ODN groups relative to the OVA mRNA + control ODN group. There was no statistical difference between the 2 OVA mRNA groups treated with either of 2 Ii AS ODNs. The median time to tumor onset was 9 days for the Flu M1 group, 17 days for the control OVA mRNA + ODN group, and 30 days for the OVA mRNA + Ii AS ODN-treated groups. Data are representative of 3 experiments.