FIG. 2.

Immune responses of mice immunized with pcDNA3-TS and p154/13. BALB/c mice were immunized as described in detail in Materials and Methods with pcDNA3-TS (▴), p154/13 (■), or pcDNA3 (●). Fourteen days after the last immunization, blood samples were collected and the sera were assayed for the presence of antibodies to TS by ELISA using polystyrene wells coated with recombinant TS-cat (A), or for the presence of TS-inhibitory antibodies (B). The results represent the mean values obtained from eight mice ± the standard deviations (SD). Pooled spleen cells obtained from three mice immunized with pcDNA3-TS, p154/13, or pcDNA3 were expanded for 6 days in the presence of irradiated A20J-TS cells. (C) The expanded cells were restimulated in the presence of A20J-pcDNA3, A20J-TS, A20J cells, or A20J cells coated with 1 μM TS_359-367 peptide (A20J-TS_359–367). IFN-γ was estimated in supernatants collected after 18 h. Results are expressed as averages of triplicate cultures ± SD.