FIGURE 4.

After in vitro stimulation with the relevant peptide, splenocytes from mice immunized 21 days previously were adoptively transferred into tumor-bearing mice. Immediately after adoptive transfer, those groups randomized to receive rIL-2 were given 90,000 IU of rIL-2 i.p. twice a day for 3 days. Eight days after the adoptive transfer of effector cells, mice were killed, lungs were excised, and metastases were counted in a blinded fashion. The results of the counts for each mouse are depicted in A, B, and C. The specific in vivo tumor response can be seen with splenocytes from mice immunized i.v. (A), i.m. (B), and intranasally (C). Moreover, in those groups that received only 2 × 10⁶ effector cells that had been primed with rAd-CMV1 (all panels marked with *), the addition of exogenous rIL-2 gave antitumor responses similar to those seen in mice receiving the higher dose of effector cells. Nonparametric statistical analysis was performed using two-tailed Wilcoxon’s test. An independent repetition of these experiments yielded identical results.