Stimulated Growth of Syngeneic Tumors at the Site of an Ongoing Delayed-Hypersensitivity Reaction to Tuberculin in BALB/c Mice

For both simian virus 40 (SV40)-transformed and 3-methylcholanthrene-induced fibrosarcomas of mice, when tumor cells were mixed with tuberculin and injected subcutaneously into tuberculin-sensitized syngeneic recipients, the tumor cells grew significantly faster than controls. Results were similar when tuberculin was repeatedly injected into previously established SV40 tumors in tuberculin-sensitized mice. These findings therefore provided no evidence that nonspecific cytotoxic effects on “innocent-bystander” tumor cells were produced during an intense delayed-hypersensitivity reaction to tuberculin.