Figure 3: Breadth of immune responses. BALB/c mice were immunized as described in Figure 1 and Methods section. Two weeks after the last immunization, splenocytes from immunized mice (6 per group) were pooled and the specific IFN-? responses were evaluated in vitro against 18 individual HIV-1 peptides encoded by the vaccines (5ÁM). The pie charts show the frequencies of HIV-1 peptide-specific IFN-? secreting cells by displaying each number of SFU/106 cells for each positive peptide as a proportion of the sum of SFU/106 cells for all positive peptides. The sum of all positive responses (SFU/106 cells) is shown above each pie chart. Splenocytes from control groups (pVAX1 and/or Ad5-▀gal) presented negligible numbers of IFN-? secreting cells after stimulation with each of the 18 encoded peptides. SFU, spot-forming units. Cutoff: 15 SFU/106.