CD8A and neoplasm: Since memory T cells have less stringent requirements for activation than naïve cells e.g., responsiveness to lower concentrations of antigen, (Curtsinger et al., 1998, Pihlgren et al., 1996, Rogers et al., 2000), we hypothesized that memory CD8 T cells were more efficiently activated during tumor re-challenge, resulting in accumulation in the spleen as early as day 66 (9 days after re-challenge).