Figure 4.

Graft-versus-tumour (GVT) effect induced by intra-bone marrow–bone marrow transplantation (IBM-BMT) with or without adult thymus transplantation (ATT). Lethally irradiated BALB/c mice with Meth-A sarcoma underwent transplantation with 2 × 10⁷ B6 bone marrow cells (BMCs) by IBM-BMT with or without ATT or spleen cell injection [donor lymphocyte infusion (DLI)] from the same donor. (a) Representative findings for tumours (arrows) in non-treated mice, or in mice treated with IBM-BMT with or without ATT 28 days after BMT. (b) The time-course of tumour growth after transplantation in mice following IBM-BMT with or without ATT or DLIs (high dose, 1 × 10⁷; low dose, 3 × 10⁶ B6 spleen cells) or non-treatment. The mice treated with IBM-BMT + ATT showed significant tumour regression, in contrast to the non-treated mice and the mice treated with IBM-BMT or IBM-BMT + a low DLI. The mice treated with IBM-BMT + a high DLI showed similar results, but they died early as a result of GVHD. IBM-BMT alone, n = 8; IBM-BMT + ATT, n = 12; IBM-BMT + a high DLI, n = 8; IBM-BMT + a low DLI, n = 10; non-treatment, n = 7. Data are shown as mean ± standard deviation (SD). *P < 0·05 compared with IBM-BMT + a low dose of DLI, IBM-BMT + a high dose of DLI and IBM-BMT + ATT; **P < 0·05 compared with IBM-BMT, IBM-BMT + a low dose of DLI, IBM-BMT + a high dose of DLI and IBM-BMT + ATT; ***P < 0·05 compared with IBM-BMT, IBM-BMT + a low dose of DLI and IBM-BMT + ATT. ^#P < 0·05 compared with IBM-BMT + a low dose of DLI, IBM-BMT + a high dose of DLI and IBM-BMT + ATT; ^##P < 0·05 compared with IBM-BMT + ATT; ^###P < 0·05 compared with IBM-BMT + a low dose of DLI and IBM-BMT + ATT. ^§P < 0·05 compared with IBM-BMT + ATT; ^§§P < 0·05 compared with IBM-BMT + ATT. ^†P < 0·05 for short survival time in IBM-BMT + a high dose of DLI compared with other groups.