Differences in immunogenicity between the local tumor 3LL and its metastasis-derived line as detected by sensitization with antigen-fed macrophages.

Macrophages fed with solubilized membrane extracts of the Lewis lung carcinoma 3LL were used to sensitize normal spleen cells in vitro. The injection of these spleen cells into the foot pad of normal syngeneic recipients 5-7 days prior to the inoculation of a lethal tumor dose into the same foot pad resulted in a significant reduction in the rate of growth of the local tumor. Moreover, the intraperitoneal injection of the sensitized spleen cells into tumor-bearing mice 6 days prior to tumor amputation caused a considerable decrease in the postoperative lung metastasis. In contrast, spleen cells sensitized in a similar manner on monolayers of macrophages fed with solubilized extracts of the metastasis-derived 3LL (M-3LL) line failed to induce such efficient host protection against either the local growth or the metastasis of 3LL.