Figure 5.

Effect of sustained CTLA-4 blockade on the response of tumor-bearing mice to immunization. Tumor-bearing or tumor-free mice received anti-HA TCR⁺ transgenic T cells on day 0 and were treated with anti-CTLA-4 antibodies every 3 days from day −1 to day +14 after the transfer of T cells, or received no treatment. On day +9, half the mice in each group were immunized with vacc-HA, and all mice were analyzed 6 days later. (A) HA-specific proliferative response of T cells from unimmunized (solid bars) or vacc-HA-immunized (interrupted cross-hatched bars) mice was determined. Three mice per group were analyzed. In a parallel plate T cells from A were cultured with medium alone or HA peptide plus fresh BALB/c splenocytes for 48 hr. Then, supernatants were collected and assayed for IL-2 (B) and IFN-γ (C) by ELISA.