Effects of in-vivo administration of a monoclonal antibody specific for the interleukin-2 receptor on the acute graft-versus-host reaction in mice.

Parental strain T lymphocyte injected into F1 mice respond to allogeneic MHC antigens and so induce the symptoms of a graft-versus-host reaction (GVHR). We have measured the local GVHR by the popliteal lymph node assay, and showed the suppression of the local GVHR in mice by treatment with the monoclonal antibody (MoAb) AMT-13 which is specific against the interleukin 2 (IL-2) receptor on activated mouse lymphocytes. The inhibitory effect of the AMT-13 administration was comparable with the suppression of the local GVHR by treatment with L3T4, an MoAb directed against the T helper subset. The L3T4 administration caused a dramatic decrease in the proportion of the cells with the L3T4 phenotype in the circulation and a marginal reduction of these cells in the lymph nodes. In contrast, the AMT-13 treated mice showed no changes in the distribution of the T lymphocyte subsets besides those in the GVHR-stimulated lymph nodes. Obviously, only the small subset of antigen-activated IL-2 receptor-bearing lymphocytes was influenced by treatment with AMT-13. MoAb directed against antigens whose expression is restricted to activated lymphocytes, such as the IL-2 receptor, might become useful for a short term immunosuppression with limited side effects.