WT1 peptide vaccination is protective but not therapeutic against tumor challenge. (A) Prophylactic vaccination scheme. One to 4 subcutaneous vaccinations of 100 ug of WT1 peptide and 100 uL of Incomplete Freund's Adjuvant (IFA) or 100 uL of IFA alone were administered weekly before intravenous tumor challenge with 1 × 105 FBL3 cells on day 0. Representative bioluminescence demonstrates disseminated tumor by 14 days after tumor inoculation in unvaccinated mice. (B) Survival of C57BL/6 mice after tumor challenge and 4 weekly vaccinations with IFA alone (○) compared with 1 (♦, P = .002), 2 (■, P < .001), 3 (●, P < .001), or 4 vaccinations (▴, P < .001) with WT1 peptide and IFA (n = 10 mice per group). (C-D) Survival of LP/J and C3H.SW mice after 4 weekly vaccinations with IFA alone (○), or WT1 peptide and IFA (●) before tumor challenge (C, LP/J P < .001; D, C3H.SW P < .001). (E) Therapeutic vaccination scheme. Subcutaneous vaccinations of 100 ug of WT1 peptide and 100 uL of IFA or 100 uL of IFA alone were administered weekly starting 24 hours after intravenous inoculation of 1 × 105 FBL3 cells on day 0. (F) Survival of C57BL/6, C3H.SW, or LP/J mice after intravenous inoculation with 1 × 105 FBL3 cells on day 0 and vaccination on day 1, 8, 15, and 22 with WT1 peptide and IFA (closed symbols) or with IFA alone (open symbols; C57BL/6, ■ vs □, P < .001; C3H.SW, ▴ vs Δ, P < .001; LP/J, ● vs ○, P < .001). There were 10 mice per group in all experiments with survival monitored at least every other day.
