<i>In vitro</i> cytotoxicity and <i>in vivo</i> tumor enhancement induced by mouse spleen cells autosensitized <i>in vitro</i>

Abstract

Abstract The immuno‐reactivity of C57BL mouse spleen cells previously sensitized in vitro against syngeneic fibroblasts or syngeneic 3LL Lewis tumor cells was investigated. The sensitized spleen cells were assayed in vitro to test their cytotoxicity against the 3LL tumor cells. In addition, spleen cells autosensitized against syngeneic fibroblasts were mixed with 3LL tumor cells and injected into syngeneic recipient mice in order to ascertain their influence on tumor growth. The in vitro assay indicated that lymphoid cells specifically sensitized against either fibroblasts or tumor cells were equally cytotoxic against the 3LL target cells. On the other hand, in the in vivo experiments lymphoid cells sensitized against syngeneic fibroblasts promoted the growth of the 3LL tumor. An attempt to explain the underlying mechanisms involved in the paradoxical behavior of autosensitized lymphocytes is reported herein.