INTRA-PINNA INDUCTION OF SPECIFIC ANTITUMOR IMMUNE T-CELL FUNCTIONS -EFFECT OF EAR RESECTION AFTER ANTIGEN APPLICATION

Upon inoculation of highly metastatic ESb lymphoma cells into the ear pinna of syngeneic mice a potent specific antitumor immune response is induced which prevents the outgrowth of the tumor cells at this parti cular site. When the tumor cell inoculated pinna was resected at diffe rent times after antigen application, systemic protective antitumor im munity, tested by s.c. tumor challenge 7 days later, could still be in duced. This was true even for a situation in which the pinna was resec ted as early as two hours after tumor cell inoculation. Protective ant itumor immunity was found to be even augmented when the pinna was remo ved three days after tumor cell inoculation as compared to the non-res ected situation. Pinna resection had no effect on the induction of a t umor specific cytotoxic T lymphocyte response while resection after 48 h had an augmenting effect on the delayed type hypersensitivity (DTH) response. An explanation for some of these findings was found when la cZ-labeled lymphoma cells were used for single cell detection in tissu e sections. As early as 15 min after intra-pinna inoculation dissemina ted single tumor cells were detected in the local draining lymph node as well as in the spleen. Whether these tumor cells can prime T cells for protective immunity directly or only after processing and presenta tion by specialized host cells remains to be elucidated.