IFNγ ELISPOT analysis of spleen cells from mice vaccinated with SINCP (prime) and Adeno (boost). Naive mice were vaccinated with SINCP-neu (a plasmid containing Sindbis virus genes and the gene for rat HER2/neu) and then twice, at 2-week intervals, with Adeno-neu (an E1,E2a-deleted adenovirus also containing the gene for rat HER2/neu). Spleen cells were collected 2 weeks after the second Adeno vaccination and were cultured overnight with 5 μg/ml concanavalin A, without stimulation, or with A2L2 cells at three different effector:stimulator ratios. The number of IFNγ-secreting cells was determined using a commercial ELISPOT procedure and antibody pair. Horizontal bars indicate means. IFNγ, interferon γ.