In vitro reeducated T helper cells from sarcoma-bearing mice inhibit sarcoma growth in vivo.
Spleen cells from BALB/c mice bearing a small, but already clinically evident transplantable methylcholanthrene-induced sarcoma (CE-2) are not able to release interferons, proliferate and perform a cytotoxic response against CE-2 cells, nor able to inhibit their growth in vivo in a Winn-type neutralization assay. They can, however, be reeducated to be efficiently active against the tumor. Spleen cells (25 X 10(6) ) and 10(6) mitomycin C-treated CE-2 cells were cultured in 20 ml of medium for 6 days. The surviving spleen cells were then cultured for another 5 days under the same conditions plus 10% interleukin 2-rich supernatant from a clone of EL-4 thymoma cells stimulated with phorbol-12-myristate-13-acetate. Reeducated spleen cells were then able to inhibit the growth of a 100% lethal dose of CE-2 tumor cells in a Winn-type assay, even when the lymphocyte to tumor cell ratio was 5:1. In vitro, they released interferon-gamma when restimulated by CE-2 cells, and displayed a marked cytotoxicity in an 18-hr assay. Their in vivo tumor-neutralizing activity was not affected by the removal of Lyt-2.2+ lymphocytes, nor by the absorption of cytolytic cells on CE-2 monolayers. The absorbed cell population no longer contained cytotoxic cells nor cytotoxic cell precursors, but still contained CE-2-specific helper cells, which assist the in vitro induction of cytotoxic cells by normal thymocytes. Lyt-2.2-, noncytotoxic, reeducated spleen cells from tumor-bearing mice thus play an important role in tumor neutralization in vivo.
D000818:Animals; D002471:Cell Transformation, Neoplastic; D003602:Cytotoxicity, Immunologic; D005260:Female; D007111:Immunity, Cellular; D007167:Immunotherapy; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000628:therapy; D013154:Spleen / Q000276:immunology / Q000473:pathology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D007371:Interferon-gamma