Intravenously (i.v.) or subcutaneously (s.c.) injected T1699 tumor cell subpopulations (Ts, and TLI-I) were destroyed more rapidly in BALB/c nu/nu athymic mice than in syngeneic DBA/2J mice. The tumor of artificial pulmonary metastases of TLI-I tumors was significantly lower, and the growth rate of s.c. Ts, and TLI-I tumors was correspondingly slower in the nude mice. No macroscopic outgrowth of pulmonary metastases of Ts tumors was detected in either group of s.c. tumor-bearers, even though the s.c. tumors progressed and killed the hosts. Unexpectedly, however, s.c. implantation in normal DBA/2J mice of lung homogenates not only from DBA/2J but also from s.c. Ts tumor-bearing BALB/c nu/nu mice produced tumors, suggesting that significant numbers of clonogenic Ts cells were present in the lungs of animals without spontaneous outgrowth of pulmonary metastases. Perturbations of s.c. Ts tumor-bearing DBA/2J or BALB/c nu/nu mice with immunosuppressive drugs or with anti-mouse thymocyte serum, respectively, induced rapid outgrowth of pulmonary metastases.
ASJC Scopus subject areas
- Cancer Research