FIG 6.

CD4⁺ T cells contribute to vaccine-induced cytotoxicity. CB6F1 mice were vaccinated three times at 2-week intervals with NS3 pepmix formulated in CAF09, as indicated. Ten days after the final vaccination, CFSE-labeled target cells from naive mice were pulsed with the single peptide p46 or p60 or left untouched and injected i.v. into vaccinated mice. Eighteen hours postinjection, splenocytes were isolated and analyzed by flow cytometry to determine killing of target cells. (A) Lymphocytes were gated based on their FSC versus SSC profiles (top), and the target cell populations were identified based on their CFSE fluorescence and MHC-II expression (bottom). (B) Histograms showing specific lysis of CFSE^high cells pulsed with p46 (top) and CFSE^low cells pulsed with p60 (bottom) in vaccinated mice. (C) Specific percent killing of target cells pulsed with p46 (top) and p60 (bottom) within the two vaccination groups. The data show means and SEM (n = 6). *, P < 0.05; **, P < 0.01.