Analysis of the response of lymphocytes in syngeneic mixed lymphocytetumor cell culture (SMLTC)

Inducdon of interleukin 3 production

Abstract

Mitogenic responses and lymphokine productions of spleen cells of C3H/He mice in mixed culture with syngeneic tumor cells (mixed lymphocyte tumor cell culture, SMLTC) were studied. Spleen cells of C3H/He mice showed a mitogenic response to X5563, MH134 and MM48, syngeneic tumor cells expressing major class I histocompatible antigen (MHC), but not to MM46 without an expression of either class I or class II antigen. Mitogenic responses to these syngeneic tumor cells could be observed on day 1 and peaked on day 3. Accompanying this mitogenic response, an activity to induce proliferation of FDC-P 2 cells, a responder for interleukin 3 (IL-3), was detected in the SMLTC fluids. Interleukin 2 (IL-2) nor interferon (IFN) activities were not found in the culture fluids throughout the 2 weeks observation period. The chromatography on FPLC MonoQ column of the condensed SMLTC culture fluids revealed that the proliferative activity against FDC-P 2 was eluted from the column with the same pattern as those of IL-3 found in the culture fluids of WEHI-3 and EL-4 cells. Neither IL-2 nor IFN activity was found in the condensed SMLTC supernatants and their effluents from MonoQ column.
Next, generation of cytotoxic effector cells against a stimulator cell line and an activity of natural killer (NK) cells in each SMLTC system were examined. The results showed that both cytotoxic activities, of which the generation required IL-2 and IFN, could not be found. In the SMLTC system, in which IL-3 production could be observed, a cytotoxic activity against MethA cells, a target for natural cytotoxic (NC) cells, was induced. These results indicate that tumor cells in interaction with syngeneic spleen cells induce mitogenic responses and produce IL-3 and IL-3-dependent nonspecific NC-like cells, but not IL-2 and IL-2 dependent their cytotoxic T cells and NK cells.