Figure 7.
Enhancement of immune responses with SFV-IL-12 + anti-CD137 combined therapy. C57BL/6 female mice were subcutaneously inoculated with 5 × 105 B16-OVA cells on day 0 and then received intratumorally saline or 108 viral particles (vp) of SFV-IL-12 on day 7. On days 7 and 10 mice received intraperitoneally 100 µg of rat immunoglobulin G (IgG) or anti-CD137. (a) At day 1 after treatment onset, mice were bled and sera samples were analyzed by enzyme-linked immunosorbent assay (ELISA) to determine interferon γ (IFNγ) concentrations. The results are represented as the mean ± SEM (n = 4 per group). ND, not detected. (b) On day 14, mice were sacrificed and spleens were processed to carry out an IFNγ enzyme-linked immunospot (ELISPOT) assay using OVA or tyrosine-related protein (TRP)-specific peptides for stimulation. The data are represented as number of IFNγ-producing spots per 106 splenocytes. (c) In-vivo killing assay. On day 13, tumor peptide-pulsed splenocytes from naive CD45.1 mice were injected to treated mice and 20 hours later mice were sacrificed and spleens collected. The percentage of specific cell lysis was quantified by flow cytometry. The set histograms in the right show representative cases of this experiment. n.s., not significant; *P < 0.05; **P < 0.01. α, anti-; SFV-IL-12, Semliki Forest virus encoding interleukin-12.