Immunotherapy Combination Regimens for Tumor Rejection

An inoculum of 10⁶ tumor cells was injected s.c. on the flank of mice in 50 μL sterile PBS. Eight days following injection, treatment was initiated as indicated (Fig. 1a). The tumor-targeting antibody (A) was administered at 100 μg per dose i.p. for B16F10 and DD-Her2/Neu models. 2.5-Fc was was administered at 500 μg per dose (i.p.). MSA-IL2 (I) was administered i.p. at 30 μg (6 μg molar equivalent IL-2) per dose. Anti-PD-1 (P) (clone RMP1-14, BioXCell) was administered at 200 μg i.p. The vaccine, composed of 1.24 nmol amph-CpG and 20 μg of amph-peptide, was administered s.c. at base of the tail, half the dose given on each side. For experiments exploring other quaternary combos, the following doses were used as indicated in Supplementary Fig. 3: anti-CTLA-4 (clone 9D9, BioXCell) was administered at 200 μg per dose i.p., IFN-α was administered at 50 μg per dose i.p., IL-15 superagonist at 4 μg per dose i.p., and anti-TGF-β at 100 μg per dose i.p. Mice were randomized into treatment groups on day 8 following tumor inoculation, immediately prior to treatment. Tumor size was measured as an area (longest dimension x perpendicular dimension) three times weekly, and mice were euthanized when tumor area exceeded 100 mm². Mice that rejected tumors were rechallenged as indicated with 10⁵ tumor cells s.c. on the opposite flank.