Fig. 4.

TCR-td CD4⁺ T cells provide in vivo help for CD8 T cell-mediated tumor rejection. C57BL/6 mice received nonmyeloablative radiation (600 rad) and then 12 h later were injected s.c. with 3 × 10⁶ EL4 NP tumor cells. (A) A further 24 h later, mice received 10⁶ TCR-td CD4⁺ T cells with 10⁴ TCR-td CD8⁺ T cells (open triangles), 10⁶ TCR-td CD4⁺8⁺ T cells with 10⁴ TCR-td CD8⁺ T cells (crosses), 10⁶ mock-td bulk T cells (open squares), or PBS (diamonds). (B) In a separate tumor protection experiment, mice were conditioned and tumor-challenged as above, followed by transfer of 10⁶ mock-td CD4⁺ T cells with 10⁴ TCR-td CD8⁺ T cells (open squares), 10⁶ TCR-td CD4⁺ T cells with anti-CD8-blocking antibody (filled diamonds), or 10⁶ TCR-td CD4⁺ T cells with 2 × 10⁴ TCR-td CD8⁺ T cells (open triangles).