A "prime-pull" immunotherapy approach using a lentiviral vector and intratumoral TLR4 agonist redirects cytotoxic T cells

Methods B16F10-OVA melanoma bearing C57BL/6 mice were immunized with the lentiviral vector DCVex on 10 days after tumor challenge to induce OVA specific effector and memory CD8 T cells. Mice were then treated 12 days later intratumorally with the TLR4 agonist GLAAS (glucopyranosyl adjuvant system), which induces the T cell homing chemokines CXCL9 and CXCL10. Control mice received no treatment or only intratumoral GLAAS injection. Tumors were excised, homogenized, and the number and phenotype of OVA-specific infiltrating lymphocytes were analyzed via flow cytometry by staining cells with phenotyping cell surface markers and OVA-pentamers. Analysis was done 0, 24, and 48 hours after GLAAS injection.