We have examined the effect of IL-12-producing cellular vaccines on the cytotoxicity and proliferative potential of CD45+ tumour-infiltrating cells (TIL) in mice carrying syngeneic TC-1 and TC-1/A9 HPV 16-associated tumours after chemotherapy with CBM-4A ifosfamide derivative. The chemotherapy resulted in the decrease of the CD4+ and CD8+ TIL, increase of the Gr-1+/CD11b+ TIL, no changes in the infiltration with CD4+/CD25+ Treg TIL, and decrease of the cytolytic and proliferative potential of the CD45+ TIL. Subsequent immunotherapy with the IL-12-producing, genetically modified TC-1 (TC-1-IL-12) cells increased tumour infiltration with CD8+ and CD4+ cells, decreased the Gr-1+/CD11b+ cells, and increased the cytolytic and proliferative potential of the CD45+ TIL. Taken together, these findings suggest that peritumoral administration of the IL-12-producing cellular vaccine can restore the cytolytic potential and inhibit immunosuppressive TIL-dependent mechanisms in the individuals bearing HPV 16-associated tumours, and explain our previously described tumour-inhibitory effects of the vaccine in mice with minimal residual disease after the tumour chemotherapy.

Institute of Molecular Genetics Academy of Sciences of the Czech Republic v v i 142 20 Prague 4 Czech Republic

The role of immune cell subpopulations in the growth and rejection of TC-1/A9 tumors in novel mouse strains differing in the H2-D haplotype and NKC domain

Tumor growth accelerated by chemotherapy-induced senescent cells is suppressed by treatment with IL-12 producing cellular vaccines