Vaccine-induced, AH1-specific T cells arise from donor and host.

(A) BALB/c mice received NST, DLI, and 4T1 tumor cell vaccine as described in Figure 3A. Four months after vaccine administration, splenic CD8⁺ T cells were purified and cultured for 1 week with AH1 peptide and IL-2, and viable cells were stained with L^d-IgG/AH1 dimers, biotinylated antihuman IgG, PE-streptavidin, CyChrome-conjugated anti-CD8, and FITC-conjugated anti-Ly9.1. (B) The host (Ly9.1⁺) versus donor origin of total CD8⁺ (black line) and AH1-specific CD8⁺ T cells (red line) is shown. (C-D) Same as in A and B, except that the vaccine consisted of 10⁶ CT26 cells and 5 × 10⁵ B78H1–GM-CSF cells, which were mixed together and irradiated (5000 cGy). (E) Spleen cells were taken from BALB/c mice treated with NST, DLI, and CT26 vaccine (as in C-D) and were stained directly ex vivo with FITC-conjugated anti-Ly9.1, CyChrome-conjugated anti-CD8, and PE-conjugated L^d/AH1 tetramers. (F) The host (Ly9.1⁺) versus donor origin of total CD8⁺(black line) and AH1-specific CD8⁺ T cells (red line) is shown.