FIG. 1.

Antigen plays a role in determining the induction of predominant CTL or antibody responses. Mice were intramuscularly immunized with plasmid DNA expressing Nef or Env. (A) Ten days after the third immunization, the cytolytic activity of spleen cells from mice was tested against the relevant stably transfected target cells (left), BC14H cells which express gp160, and P815-Nef cells which express Nef, or against peptide-pulsed P815 target cells (right) as detailed in Materials and Methods. The standard deviation for each triplicate point was ≤10%. Mice were injected with Env expression vectors encoding gp160 (left) or gp150 (right), respectively. (B) The antibody response was determined by immunoprecipitation followed by Western blot analysis with horseradish peroxidase-conjugated goat anti-mouse IgG (Santa Cruz Biotechnology Inc.). Each lane corresponds to the serum from an animal immunized with either the control vector (lanes 2 and 5) or a plasmid that expresses either Env or Nef (lanes 3 and 6). Mouse polyclonal serum to gp160 (HIV-1 V3 monoclonal [IIIB-V3-13], National Institutes of Health AIDS Reagent Program) and monoclonal antibody to Nef (Intracel) were used as positive controls (lanes 1 and 4, respectively).