CD8A and neoplasm: To determine whether this CD8+ Tem cell expansion in the DLN was tumor antigen specific, we labeled CD8+ T cells with an MHC class I H-2Ld–restricted Pentamer loaded with the immunodominant CT26 antigen, the AH1 peptide (SPSYVYHQF) of the murine leukemia virus gp70 envelope protein (33–35) (Figure 1C).