FIG. 4.
Immune responses of mice immunized with p154/13 and pΔ154/13. BALB/c mice were immunized with p154/13, pΔ154/13, or pcDNA3. Fourteen days after the last immunization, blood samples were collected and the sera were assayed for the presence of antibodies to recombinant TS-cat by ELISA (A) or for the presence of TS-inhibitory antibodies (B). The results represent the mean value obtained from eight mice ± the standard deviations (SD). Pooled spleen cells obtained from three mice immunized with p154/13, pΔ154/13, 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 TS359-367 peptide (A20J-TS359-367). IFN-γ was estimated in supernatants collected after 18 h. Results are expressed as averages of triplicate cultures ± SD.