Donor WT1 peptide vaccination combined with allogeneic BMT enhances antileukemic activity against FBL3. (A) Vaccination and bone marrow transplant scheme. 4 subcutaneous vaccinations of 100ug of WT1 peptide and 100uL of IFA or 100uL of IFA alone were administered weekly to C57BL/6 or LP/J donors before isolation and transfer of 2 × 107 splenocytes into lethally irradiated C57BL/6 recipients. All recipients were given also 5 × 106 T-cell depleted bone marrow cells from IFA vaccinated donors. Recipients received 5 × 102 FBL3 tumor cells intravenously 6 hours after lethal radiation and 24 hours before intravenous transfer of donor cells. Seven days after cell transfer one group of recipients received a vaccine “boost” with WT1 peptide and IFA. (B) Survival after vaccination with WT1 peptide and IFA (closed symbols) compared with IFA alone (open symbols) after syngeneic, concomitant observed controls (C57BL/6→C57BL/6, ▾ vs ▿, P < .001) or allogeneic (LP/J→C57BL/6, ● vs ○, P < .001; ▾ vs ●, P < .001) bone marrow and splenocyte transplantation (n = 10 mice per group). Some recipients were given a vaccine boost (LP/J→C57BL/6, ▴ vs ●, P = .239). (C) PBLs were isolated from C57BL/6 controls or 28 days after transplantation of C57BL/6 recipients with LP/J donor cells and assayed for staining for donor marker Ly9.1 versus TCRβ or versus B220. Left panels show representative normal control C57BL/6 mice and right panels show C57BL/6 recipients of LP/J donor transplants. (D) Plots are mean percentages of donor type cells among T cells of 5 mice per group. (E-F) Representative images of 3 mice per group and bioluminescence intensity (mean ± SE for groups starting with 10 mice per group) of albino C57BL/6 recipients at 3, 12, 24, and 36 days after bone marrow and splenocyte transplantation from IFA alone vaccinated (○) or WT1 peptide + IFA vaccinated LP/J donors with (▴) or without vaccine “boost” (●; ○ vs ● at day 12, P < .001). Blank images represent death of recipients.
