Figure 2: In vitro expression of epitope-based DNA vaccines. The expression products of epitope-based DNA vaccines were first precipitated with mouse anti-His antibody (IgG) and then detected by western-blotting. The coprecipitated heavy (55 KD) and light chains (25 KD) of mouse IgG served as internal controls. The relative expression levels were similar among pSV-Env , pSV-triEnv , and pSV-sextEnv , while, the expression of pSV-Env2 could not be detected.