Fig. 1.

a Survival of C57BL/6 and RAG1^−/− mice with B16.SIY brain tumors injected with activated 2C T cells on day 7. Control mice (dashed lines) died within 2 weeks (median survival: RAG1^−/− 14 days, C57BL/6 13 days) while mice treated with 2C T cells (solid lines) survived more than twice as long (RAG1^−/− 35 days, C57BL/6 30 days). C57BL/6 mice are represented in gray, RAG1^−/− mice in black. n = 3 per group. *P < 0.05 vs. respective control group without 2C treatment. b Immunostaining of 2C T cells in brain tumors 2 and 7 days after transfer. 2C T cells are labeled in left images with an idiotype specific antibody and Alexa-594 (red); middle images show DAPI counterstain (blue), right images are merged. Scale bar 200 μm. Images are representative of three mice. c Low or absent SIY/GFP expression by cancer cells cultured from brain tumors that recurred following adoptive T cell therapy (n = 4). GFP-negative B16-F10 cells (filled black curve) and freshly cultured B16.SIY cells (red curve) were included as negative and positive controls, respectively