ISS increases T-cell priming in FL-treated mice.

(A) Experimental design. Groups of 3 mice received daily injections of FL or PBS from day −9 to day 0. OVA in association with ISS, C-ODN, or PBS was injected SC on day 0. Seven, 12, and 18 days after immunization the draining popliteal and inguinal lymph nodes were harvested and assayed. (B) Seven days after immunization, lymph node cells were cultured for 4 days in the presence of graded doses of OVA and proliferation was measured. Results shown represent the mean of 4 separate experiments. ● indicates FL-ISS-OVA; ▪, FL–C-ODN–OVA; ■, FL-OVA; ▴, OVA alone. (C) Lymph node cells isolated 7, 12, and 18 days after immunization were restimulated in the presence of OVA_257-264 and anti-CD28 for 8 hours and then assayed for IFN-γ secretion by flow cytometry. The percentage of lymph node cells that are CD8⁺ IA-b⁻ IFN-γ⁺ is provided in the appropriate quadrant and the mean IFN-γ fluorescence intensity is in brackets. These results represent the mean of 3 different experiments.