Human immunosuppressive factors produced by T cell hybridoma

A Human OKT8-positive T cell hybridoma was established by using concanavalin A (ConA)-activated peripheral blood mononuclear cells (PBMC) fused with CEM-AGR cells. A culture supernatant of the established T cell hybridoma HI4.2D6 inhibited the mitogen induced proliferation of peripheral blood mononuclear cells (PBMC). It inhibited IL-1-, IL-2, or IL-3-dependent proliferation of each factor-dependent mouse cell lines. While the inhibitory activity of IL-1-induced proliferation was stable, that of IL-2- and IL-3-induced proliferation was abrogated within a week at 4 degrees C. Inhibition of IL-2-dependent growth was also observed using human IL-2-dependent cells, but the growth of other factor-independent human hematopoietic cell lines was not affected at all. By gel filtration, the activity inhibiting IL-2- or IL-3-dependent proliferation was found in the fractions with approximate molecular weight of 18,000 and 100,000.