Failure of Spleen Cells from Thymectomized Mice to Induce Graft vs. Host Reactions.

Abstract

Summary 1. The capacity of spleen cells from mice thymectomized during neonatal life to elicit graft vs host reactions was studied using Simonsen's graft vs host assay of histocompatibility. 2. The reaction of A strain spleen cells from mice sham operated or thymectomized in the neonatal period was compared to that of isologous F1 cells in (A × C57B1)F1 recipients and Z strain spleen cells from similarly treated groups were compared in (Z × C57B1) F1 and in the (Z × DBA/2)F1 hybrids. 3. The results show that early complete thymectomy in both A and Z mice renders the spleen cells of these animals incapable of producing graft vs host reactions in Fl hybrids. 4. These data are interpreted as evidence that the cells themselves of the lympho-reticular system in mice thymectomized at or shortly after birth are immunologically defective. 5. These observations are considered as a further evidence that the thymus plays a key role in development of immunological capacity in mammals.