Ia- Restricted interaction of normal lymphoid cells and SJL Lymphoma (Reticulum Cell Sarcoma) leading to lymphokine production. III. relative roles of reticulum cell sarcoma and normal lymphoid cells in lymphokine production

Production of interleukin 2 (IL-2) in mixed lymphocyte cultures of SJL/J lymph node (LN) and γ-irradiated, syngeneic lymphoma cells of transplantable reticulum cell sarcoma (γ-RCS) was abolished by pactamycin pretreatment of γ-RCS. LN cells needed for this interaction were Lyt-2 T-cells, not adherent to Sephadex G-10. The effect of separation of T-cells and γ-RCS after the first 24 hours of culture suggested that both components contributed to the IL-2 production. Exogenous IL-2, but not interleukin 1 (IL-1), restored the ability of pactamycin-treated γ-RCS to induce syngeneic T-cell proliferation. The inability of T-cells from “nonresponder” F1 hybrids of SJL to proliferate to γ-RCS was not corrected by addition of IL-1 or IL-2. Interferon (IFN) production also required the presence of untreated γ-RCS and LN cells, but it was dependent on a Sephadex G-10 and plastic adherent cell in LN. IFN-free supernatant of LN cells plus γ-RCS induced IFN production in fresh normal lymphoid cells, suggesting a possible indirect induction of this lymphokine. In addition, unirradiated RCS cells (la+ cells) produced immune IFN over a period of 3 weeks in vitro, after which the cells lost their viability. Prolonged IL-2 production was not observed in these cultures. The possible biological importance of the lymphokine production during the exaggerated syngeneic mixed lymphocyte reactions induced by RCS cells is discussed.