BALB/c mice were immunized as described earlier. Twenty-eight weeks after the last immunization, splenocytes from immunized mice (6 per group) were pooled, labeled with CFSE (1.25μM) and cultured for 5 days, in the presence of 5μM of pooled HIV-1 peptides. Cells were analyzed by flow cytometry and CFSE dilution on gated CD3+CD4+ or CD3+CD8+ cells was used as readout for antigen-specific proliferation. Experimental groups presented proliferation above cutoff values in all time points. The average of proliferation on splenocytes from pVAX1 and/or Ad5-βgal immunized group was subtracted from the respective experimental groups. DNA= HIVBr18; Ad5= adenovirus 5 encoding HIVBr18. DNA vs Ad5 (2x, SC), p<0.001.