FIG. 2.
Antigen-specific cytolytic activity of bulk splenic mononuclear cells harvested from mice immunized with MPL adjuvant-DNA vaccine administered via the i.m. (A) or i.n. (B) route. Splenocytes were harvested and cultured for 5 days with V3 peptide (also known as a CTL epitope of HIV-1 strain IIIB). Syngeneic cells (P815 cells) pulsed with or without the same peptide were used as targets, and the percent target cell lysis was determined by means of a 5-h 51Cr release assay. The activity was titrated with effector/target (E/T) cell ratios of 5, 20, and 80. Nonspecific cytolytic activity (not pulsed) was measured at an E/T ratio of 80. The results were obtained in duplicate assays and are expressed as the mean ± standard error of the mean of the four to five mice in each group. The symbol * indicates a significantly enhanced cytolytic response compared with the response of mice which received IIIB/REV alone via the same immunization route.