Endogenous activation of tumor-specific T cells in HSCT setting. Recipient mice with (A,B,D) or without (C) established tumor underwent transplantation on day 0 (D0), then were inoculated with or without 10⁷ pfu of VaccHA (subcutaneously) 15 days (A,B) or 35 days (C,D) after HSCT/adoptive transfer, and killed 6 days later. Percentage of HA-specific T cells (A) and IFNγ production in response to HA peptide (B-D) in recipient mice was measured. Values are means plus or minus SE of triplicate cultures from 3 mice in each group.