FIG. 4.

Phenotypic analysis of p18-specific CD8⁺ T cells elicited by DNA vaccination with or without delayed administration of plasmid IL-12. BALB/c mice were immunized with 50 μg of PMV-gp120 alone (black bars) or with 50 μg of PMV-gp120 plus 200 μg of PMV-IL-12 on day 10 following vaccine administration (checkered bars). Spleen cells were harvested from individual mice at the indicated times, and the expression of CD11a (A) and CD54 (B) on gated H-2D^d/p18 tetramer-positive CD8⁺ T cells was measured by flow cytometry. Expression of these molecules on CD8⁺ T cells from naive animals is also indicated (hatched bars). Data are presented as the mean fluorescence intensity (MFI) and represent the means of four mice per group ± SEM.