Interleukin 4 (IgG1 induction factor): a multifunctional lymphokine acting also on T cells

Abstract

A cDNA encoding the murine interleukin 4 (IL4) (IgG₁ induction factor/B cell‐stimulating factor no. 1) was recently cloned (Noma et al., Nature 1986. 319: 640; Lee et al., Proc. Natl. Acad. Sci. USA 1986. 83: 2061). In this report we tested recombinant IL4 in various T cell assays. It was found that IL4 activated the murine T cell line CTLL to increased DNA synthesis but not to growth. It also activated normal concanavalin A (Con A)‐stimulated T cells both to increased DNA synthesis and to growth. These T cell growth factor‐like activities were not inhibitable by anti‐IL2 receptor antibodies. Evidence is given that both Lyt‐2⁺ and L3T4⁺ T cells responded to IL4. Finally, IL4 acted synergistically with phytohemagglutinin or Con A on normal T lymphocytes as well as on thymocytes. These data, as well as those of others, imply that lymphokines have a broader range of activity than previously anticipated.