Activation of P1A-reactive T cells in the periphery of tumor-bearing mice. Spleen cells from the chimera mice reconstituted with bone marrow from BALB/c P1CTL and BALB/c mice as described in Figure 1 were analyzed for the phenotype and number of P1A-specific T cells. (A) Expansion of P1A-specific T cells in the spleens of tumor-bearing mice. Spleens from chimera mice were stained with anti-CD8, and L^d:P1A dimer or anti–Vα8 TCR. FACS plots are representative profiles of cells within the lymphocyte gate. Graph depicts mean ± SEM of 6 to 7 mice/group. This trend of expanded P1A-specific T cells in tumor-bearing mice is representative of 2 independent experiments. (B) Phenotype of P1A-specific T cells from tumor-bearing and nonbearing mice. Data shown are CD44 and CD62L profiles of gated CD8⁺Vα8 TCR⁺ T cells. A representative profile from each group is presented on the left, whereas the graph on the right depicts the mean ± SEM of 3 mice/group and is representative of 2 independent experiments.