Fig. 3.

CVB3-specific T cell response elicited by intranasal immunization with VSV-based vaccine or DNA in chitosan formulations. Two weeks after final DNA immunization, spleen and MLN cells were collected from immunized mice and expanded in vitro with VP1_237–249 peptide. (A) CVB3-specific T cell proliferation was assessed by Roche BrdU-Kit after stimulation with 20 μg/ml VP1_237–249 peptide in the culture of 20 U/ml IL-2 for 72 h. (B) CVB3-specific cytokine-secreting lymphocytes were quantified by ELISPOT assay in response to CVB3 VP1_237–249 peptide or inactivated CVB3 for 48 h. (C) CVB3-specific CTL activity of splenic and mesenteric cells was evaluated by lactate dehydrogenase assays using pcDNA3.1-VP1 stable-transfected autologous SP2/0 cells as target cells. The effector/target cell ratio was between 50:1 and 12.5:1. Results are represented as the mean ± SD (n = 6) of three separate experiments.^*P < 0.05, ^**P < 0.01, ^***P < 0.001.