FIGURE 5.
Booster vaccination with DRibble-loaded B cells delayed the tumor growth in an established BNL murine hepatocellular carcinoma model. A, B-cell therapy scheme in an established BNL murine hepatocellular carcinoma model. Immunocompetent BALB/c mice (n=5) with preestablished BNL tumors (previously injected with 2×106 BNL tumor cells) were treated with DRibbles injected directly into both inguinal lymph nodes. Two intravenous injections of 5×106 DRibbles-loaded B cells or unloaded B cells 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 frequency of CD8+ and CD4+ T cells infiltrated the 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). F and G, Lymphocytes were collected from lymph nodes and spleens of vaccinated mice were restimulated with DRibbles. The frequency of interferon (IFN)-γ-producing T cells and secreted IFN-γ were detected by intracellular cytokine staining 12 hours later (F) and ELISA 72 hours later (G), respectively. *P<0.05, **P<0.01. Data are representative of 3 independent experiments with similar results.