Immunological reconstitution of tumour-transplanted and thymus-grafted nude mice.

Two different malignant tumours were transplanted prior to or after thymus grafts in nude mice, and the degree of immunological reconstitution was studied. All mice which rejected either of the tumour types had reconstitution as expressed by an excess of splenic plaque-forming cells. The level of response was dependent upon the age of the thymus graft and whether a tumour was transplanted or not. In contrast, the result of the phytohaemagglutinin stimulation assays of spleen cells were always subnormal in thymus-grafted as well as in thymus- plus tumour-transplanted mice.