T cell infiltration and induction of tumor cell death in cervical and lung tumor tissue. Cervical (Caski and HeLa) and lung (A549) tumor cells were injected into T cell engrafted NOD/SCID mice. Mice were sacrificed at 8 weeks later, and the remaining tumor was prepared. A, frozen tumor sections were stained for human CD4 (FITC) and CD8 (PE) from Caski (left), HeLa (middle), and A549(right) (upper panels), CD8 (FITC) and CD45RO (PE) from Caski (left), HeLa (middle), and A549(right) (bottom panels). B, for detecting apoptotic cells, tumors with Caski only (upper) and Caski with T cells (bottom) (left panels), HeLa only (upper) and HeLa with T cells (bottom) (middle panels), and A549 only(upper) and A549 with T cells (bottom) (right panels) was investigated with the TUNEL assay. Cell nuclei are indicated with blue fluorescent Hoechst counterstaining.