Selective localization of tumor-immune spleen cells at the tumor challenge site after adoptive transfer of line 10 tumor immunity in strain 2 guinea pigs.

Abstract

In this study, the distribution of immune spleen cells was investigated after adoptive transfer of immunity in inbred strain 2 guinea pigs. Spleen cells obtained from line 10 immune donor animals became specifically restimulated in vitro with 3 M KCl-extracted line 10 soluble proteins, but not with 3 M KCl-extracted line 1 or liver proteins. After 4 days culture in vitro, these specifically restimulated immune spleen cells retained their antitumor activity in vivo after adoptive transfer. The specifically restimulated immune spleen cells were radiolabeled with [3H]thymidine, 1 X 10(8) viable cells were adoptively transferred in tumor-bearing guinea pigs, and their distribution was investigated. As controls for the specific localization of the immune cells at the line 10 tumor, the presence of labeled cells was studied in the contralateral transplanted line 1 hepatoma as well as in cellular inflammatory reactions elicited by injection with incomplete Freund's adjuvant (IFA) and complete Freund's adjuvant (CFA). A significantly higher localization of the labeled immune spleen cells in the line 10 tumor and the first and second draining lymph nodes of the line 10 challenge site were found when compared to the influx of these cells in the line 1 tumor and the nontumor antigen-related inflammatory reactions. Because our immune donor animals were immunized with a mixture of line 10 cells and BCG, these animals are immune to both. Line 10 immune spleen cells were restimulated in vitro with PPD and were radiolabeled. These PPD-restimulated immune spleen cells showed no preferential localization at the line 10 tumor challenge site but, as expected, a tendency for localization at the CFA (H37Ra) injection site. Furthermore, PPD-reactive spleen cells from BCG-immunized guinea pigs showed a significantly higher accumulation at the CFA injection site compared to the IFA injection site and the line 10 and line 1 tumor challenge site. From the results, it is concluded that line 10 tumor-immune and BCG-immune spleen cells are two distinct cell populations, and that the existence of cross-reacting antigens between BCG and the line 10 hepatocarcinoma are of no importance for the rejection of the line 10 tumor by immune spleen cells.