Murine tumorlytic factor, immunologically distinct from tumor necrosis factor-α and -β, induced in the serum of mice treated with a T-cell mitogen of Corynebacterium kutscheri

Abstract Murine tumorlytic factor (TF), immunologically distinct from murine tumor necrosis factor (TNF)-α and -β, was purified to a homogeneity from the serum of mice injected with a T-cell mitogen of Corynebacterium kutscheri . The treated mouse serum was purified by Lentil lectin-Sepharose chromatography, DEAE-cellulose chromatography, preparative isoelectric focusing, and high-pressure liquid chromatography to the specific activity of 1.5 × 10 6 U/mg protein. TF was 42 kDa in its oligomeric form and 14 kDa in its monomeric form. TF activity was not impaired with hamster monoclonal antibody (mAb) to recombinant murine TNF-α and -β and, reciprocally, rabbit antibody to TF neutralized the bioactivity of neither murine TNF-α nor -β. TF was not precipitated with the mAb to murine TNF-α and -β in Western blot analysis. The partial amino acid sequence of TF was at most 33% homologous to the 46–63 sequence of mouse TNF-β. Thus, these results suggest that TF might be a novel tumorlytic factor which is immunologically distinct from mouse TNF-α and -β.