Transplantable Polyomavirus-Induced Salivary Gland Epitheliomas Are Populated by Immature T Cells Derived from the Host

Transplantable, polyomavirus-induced salivary gland epitheliomas were passaged through F1-hybrid mice of C3H/Bittner with BALB/cJ or AKR/J strains and congenic nu/nu athymic mice on the BALB/c background. By analysis of the Thy-1 and Ly-2 (CD8a) alloantigens of the T cells that infiltrated the transplanted tumors, it has been determined that the lymphocytes were derived from the host and not the donor of the epithelial tumor. It is known that the tumor masses in the FL-hybrid and athymic mice were not the result of a secondary tumor induction or transformation of host tissue because the epithelioma could be transplanted back into the strain of origin, C3H/Bittner. Intratumor lymphocytes resembled thymocytes on the basis of their intense staining by anti-Thy-1 reagents, the presence of large fractions of cells that bore both CD4 and CD8a, and the cell-size distribution of the phenotypes. Nu/nu mice carrying epitheliomas infiltrated with host-origin T lymphocytes were not immunologically reconstituted, as judged by the lack of T cells in the spleens of such tumor hosts. The epithelial tumors acted as sites of host T-lymphocyte maturation, but the process was incomplete, and mature T cells did not emigrate to the periphery.