Fig. 2.

Tumor progression is associated with lack of Tag-specific CD8⁺ T cell response in immunocompetent mice. Splenic lymphocytes were isolated from mice inoculated with two different doses of SV40 Tag transgenic hepatocytes via ISPL injection, or immunized i.p. with B6/WT-19 cells and control HSS, respectively. (A) The frequency of Tag epitope I- or IV-specific CD8⁺ T cells was determined via ex vivo staining with MHC Db/I and Kb/IV tetramers at the indicated times post immunization. Pooled results for each group are shown for both epitope I (B) epitope IV (C) specific T cells. n=4 (D) The frequency of Tag peptide I or IV-specific IFN-γ-producing CD8⁺ T cells in the splenic lymphocytes were determined in parallel via intracellular cytokine staining. Combined results for all mice are shown in (E) (epitope I) and (F) (site IV). n=4; error bars represent mean ± S.D.