Role of cytokines in GVL (ESb lymphoma) and GVHD after adoptive transfer of allogeneic T lymphocytes in mice

ESb lymphoma cells injected i.v. into DBA/2 (H-2(d)) mice multiply rapidly in the liver and kill all mice in a few days. Adoptive transfer of allogeneic C57BI/6 (H-2(b)) tumor-immune or normal splenic lymphocytes to sublethally irradiated DBA/2 mice induced a marked antitumor state, graft- versus-leukemia (GVL), increasing the mean survival time 2-3-fold, but also induced an acute and lethal graft-versus host disease (GVHD). We have undertaken experiments to try to dissociate GVL from GVHD. Transfer of immune spleen cells induced a greater GVL than transfer of normal spleen cells with an equivalent to GVHD. Three to five million immune or normal CD8⁺ T lymphocytes were sufficient to induce both GVL and GVHD. Individual DBA/2 mice were labeled and followed. In mice undergoing GVHD, the spleens were repopulated by donor (H-2(b)) lymphocytes, and tumor necrosis factor-α (TNF- α) and interleukin-6 (IL-6) were present in the sera of 26 of 27 and 18 of 20 mice, respectively, together with increased amounts of TNF-α and IL-6 mRNA in their spleens. This was in contrast to DBA/2 mice receiving allogeneic cells but not developing GVHD. Both interferon-α/β (IFN-α/β) and IL-12, which had proven very effective in association with adoptive transfer of syngeneic immune T lymphocytes in inhibiting ESb metastases, enhanced GVHD when administered with allogeneic immune or normal spleen cells, and >90% of mice died. Intensive IL-2 treatment inhibited GVHD while maintaining GVL.