Immune (y) Interferon Produced by Murine T-Cell Lymphomas

Abstract

Various cloned murine T-cell hybridomas and T lymphomas were evaluated for their ability to produce immune (y) IFN and other lymphokines such as interleukin-2 (IL-2) and macrophage activiating factor (MAF). The 2 T-cell clones, L12-R1 and -R4, dereived from a spontaneously in vitro transformed cell line L12 which was originally established from fetal calf serum (FCS)-primed C57BL/6 spleen cells (Rubin et al., 1980, Scand. J. Immunol. 12:407) were found to produce IFN after mitogen stimulation (1.000 IU) in presence of 2% FCS. By contrast in complete absence of FCS IFN titres decreased to 500 IU. None of the cell lines tested produced IFN either constitutively or upon lipopolysaccharide (LPS) stimulation. The IFN was characterized as immune (y) IFN by being labile at pH 2 and neutralized by 2 rabbit anti-murine IFN-y antisera but not by antiserum to murine IFN-α and -β. L12-R4 IFN-y chromatography on Sephacryl S-200 and Phenyl Sepharose columns indicates a molecular weight of about 45.000 and a significant apparent hydrophobicity just as other murine IFN-y. In addition to IFN-y IL-2 and MAF were also found in the supernatants of the mitogen treated L12-R4 cells. Our data provide further evidence that IFN-y is a product of T cells of the Lyt-1⁺, 23^- phenotype and establish a system which could be used for the IFN-y purification as well as for the characterization of the molecular mechanisms involved in T cell differentiation leading to IFN production.