CD8(+) T cells are crucial for the ability of congenic normal mice to reject highly immunogenic sarcomas induced in nude mice with 3-methylcholanthrene

An attempt was made to identify the selection pressures put upon a growing tumour by CD8(+) T cells. To this end tumours induced with 3-methylcholanth rene in T cell-deficient nude mice and in congenic T cell-competent nu/+ mi ce were transplanted to nu/+ recipients. The rejection rate of the sarcomas from nude mice was almost twice that of the sarcomas from nu/+ mice. Deple tion of CD8(+) T cells from nu/+ recipients prior to transplantation made t hem accept nude tumours that were consistently rejected by untreated nu/+ r ecipients. These findings suggest that a methylcholanthrene sarcoma during its growth in a T cell-competent host adapts to the T cell system through a selective elimination of highly immunogenic tumour cells that are suscepti ble to CD8(+) T cell-mediated lysis.