CD40 ligand-specific antibodies synergize with cyclophosphamide to promote long-term transplantation tolerance across MHC barriers but inhibit graft-vs-leukemia effects of transplanted cells  Tatyana B Prigozhina, Olga Gurevitch, Gregory Elkin, Shoshana Morecki, Elena Yakovlev, Shimon Slavin  Experimental Hematology  Volume 31, Issue 1, Pages 81-88 (January 2003) DOI: 10.1016/S0301-472X(02)01009-3

Figure 1 Experimental design: Treatment with CD40L-specific MR1 antibody for the reduction of tolerance-inducing Cy dose. BALB/c recipients and C57BL/6 (B6) donors were used in the study. Cyclophosphamide was given at a dose of 100 mg/kg or 60 mg/kg, MR1 was inoculated at a dose of 250 μg/injection. Experimental Hematology 2003 31, 81-88DOI: (10.1016/S0301-472X(02)01009-3)

Figure 2 Experimental design: Treatment for evaluation of the influence of CD40-CD40L costimulatory blockade on the GVL effects of allogeneic BM. Experimental Hematology 2003 31, 81-88DOI: (10.1016/S0301-472X(02)01009-3)

Figure 3 Estimation of the minimal dose of Cy required for induction of donor-specific tolerance to allogeneic skin grafts after low-dose or intensive recipient irradiation. (A.) BALB recipients were exposed to 6 daily fractions of TLI (200 cGy/day). After the last irradiation they were inoculated IV with 3 × 107 C57BL/6 BM cells and transplanted with C57BL/6 skin graft. One day later mice received IP 200 mg/kg Cy (n = 13), 100 mg/kg Cy (n = 19), 50 mg/kg Cy (n = 19), or 25 mg/kg Cy (n = 8). A day later recipients were transplanted IV with a second C57BL/6 BM cell graft (3 × 107 cells/mouse). Survival of recipients and acceptance of donor skin transplants are presented at day 200 after BMT. Survival of recipients treated with Cy 200 mg/kg was significantly lower than in other groups (p < 0.001), while skin engraftment was optimal with Cy 200 mg/kg and 100 mg/kg and decreased when Cy dose was reduced (pCy 100 − 50 and pCy 50 − 25 < 0.001). (B.) BALB recipients exposed to a single 200-cGy dose of TLI were treated as in section A but received 200 mg/kg Cy (n = 27), 150 mg/kg Cy (n = 18), or 3 daily injections of 70 mg/kg Cy (n = 7). A day after Cy administration (in the last case 1 day after the third Cy injection), recipients were transplanted IV with a second C57BL/6 BM cell graft (3 × 107 cells/mouse). Survival of recipients and acceptance of donor skin allografts are presented at day 200 after BMT. Mice treated with 200 mg/kg Cy survive better than after intensive irradiation and 200 mg/kg Cy (p A with Cy200 vs B with Cy200 < 0.001). Experimental Hematology 2003 31, 81-88DOI: (10.1016/S0301-472X(02)01009-3)

Figure 4 Effect of costimulatory blockade on recipient survival and acceptance of allogeneic BM and skin transplants in mice prepared for BMT by low-dose irradiation, donor BM cell transfusion, and a reduced Cy dose. MR1 mAb (250 μg/injection) was given IV before BM1, BM2, and 2 days after BM2. In group 6 the last dose of MR1 mAb was replaced by IV injection of human CTLA4Ig fusion protein (250 μg/mouse). Mice in group 2 received MR1 mAb instead of Cy. Mean values ± SD of data are presented at day 200 after treatment. N = 14 in group 1, n = 5 in group 2, n = 8 in group 3, n = 13 in group 4, n = 7 in group 5, and n = 5 in group 6. Skin engraftment: groups 1, 4, 6 differ from groups 2, 3, 5 (p < 0.01). Donor cell chimerism: groups 1, 4, 6 differ from groups 2, 3, 5 (p < 0.05) and group 1 from groups 4 and 6 (p < 0.05). Experimental Hematology 2003 31, 81-88DOI: (10.1016/S0301-472X(02)01009-3)

Figure 5 Treatment of leukemia by BMT in presence of MR1 mAb. BALB/c mice were inoculated with 106 BCL1 leukemia cells one day before conditioning for BMT (day −1), irradiated with 200 cGy TLI (day 0), and randomized into 3 groups. Group A (n = 13) was treated only with Cy (200 mg/kg IP, day 1). Group B (n = 16) received the C57BL/6 BM1 (3 × 107 cells IV) after irradiation, 200 mg/kg Cy IP on day 1, and C57BL/6 BM2 (3 × 107 cells IV) on day +2. Group C (n = 33) was treated like group B but also received IV 250 μg MR1 MoAb with BM2 and 2 days later. An additional group D was treated like group B, but received no BCL1 cells before BMT (n = 30). All mice were monitored for 150 days for survival and development of leukemia or GVHD. Experimental Hematology 2003 31, 81-88DOI: (10.1016/S0301-472X(02)01009-3)