Regression of established intradermal tumors and lymph node metastases in guinea pigs after systemic transfer of immune lymphoid cells.

Strain-2 male guinea pigs with established intradermal (id) tumors and microscopic regional lymph node metastases were treated by systemic transfer of syngeneic peritoneal exudate (PE) cells from tumor-immune guinea pigs. This treatment produced complete regressions of established id tumor nodules (10-11 mm in diameter) and prevented the growth of lymph node metastases in 32 (80%) of the 40 treated animals. All untreated animals died with progressive id and lymphatic tumor growth. Lymph node tumor metastases that remained after id tumor excision were also suppressed by immune cell transfer. PE cells from guinea pigs immune to an antigenically distinct tumor line (line-1), BCG, or PE cells from nonimmune guinea pigs failed to produce tumor regression or prolongation of survival time. PE cells from allogeneic guinea pigs and from sheep immune to line-10 failed to transfer tumor immunity to strain-2 guinea pigs. The effectiveness of therapy was reduced by increasing the tumor burden or decreasing the number of transferred lymphoid cells. This study demonstrated that systemic transfer of cells from syngeneic immune donors could effectively eliminate tumors as well as early metastases.