FIGURE 3.

Boosting with DRibble-loaded B-cell vaccine suppressed the tumor growth but generated no cure without adoptive transfer of OT-I T cells in an established E.G7 murine thymoma model. A, Experimental scheme. C57BL/6 mice (n=5) with preestablished EG7 tumors (previously injected with 5×10⁵ EG7 tumor cells) were first treated with DRibbles injected directly into both inguinal lymph nodes. Two intravenous injections of 5×10⁶ DRibbles-loaded B cells or dendritic cells (DCs), unloaded B cells or PBS were given 3 and 6 days after the first injection of DRibbles. Untreated mice served as controls. Tumor volume (B) and percentage of survival (C) in mice bearing subcutaneous tumors were monitored over time. D and E, The tumor cells were stained with antibodies against CD4 and CD8. The frequency of CD8⁺ and CD4⁺ T-cell infiltrating tumors was analyzed by flow cytometry. Percentages of CD8⁺ (D) and CD4⁺ (E) T cells are shown as mean±SEM derived from 3 mice per group (n=3). *P<0.05, **P<0.01, ***P<0.001. The typical result from 3 independent experiments was shown.