Changes in clonotype-positive T cells in H-2^d→H-2^dxb tumor-bearing chimeras.

Three months after BM reconstitution, H-2^d→H-2^dxb (A) or H-2^b→ H-2^dxb (B) chimeras received 1 × 10⁶ anti-HA CD4⁺ TCR transgenic T cells IV. One day later, half the animals in each set of chimeras were challenged with 1 × 10⁶ A20HA tumor cells given IV. On day +22 after tumor challenge, all the animals were killed, and purified splenic T cells were analyzed by 2-color flow cytometry staining for CD4 versus anti-HA TCR clonotype (MoAb 6.5). (C) Background staining was done using this antibody combination on spleen cells from BALB/c mice without transgenic T-cell transfer. Three mice were included per group. Shown are representative FACS plots from individual mice in each group. Upper right quadrant numbers: percentage of double-positive T cells.