Expression of interleukin 1 receptors is restricted to the L3T4+ subset of mature T lymphocytes.

Abstract

The polypeptide hormone interleukin 1 (IL 1) has been shown to mediate a wide spectrum of biologic activities, including fever induction, prostaglandin and collagenase production, and the proliferation and differentiation of fibroblasts, microglia, and lymphocytes, as can be reviewed in Reference. Its ability to induce both the secretion of the T cell growth factor interleukin 2 (IL 2) and the expression of IL 2 receptors (IL 2-R) by T cells has led to the proposal that IL 1 is a key regulator of the T cell-mediated immune response. It is not known for certain whether IL 1 acts on all T lymphocytes or whether its activity is restricted to distinct subpopulations such as CD4 + (L3T4 + in mouse) or CD8 + (Lyt-2 + ) cells. Recently, it has been shown that activation of L3T4 + (but not Lyt-2 + ) T cells is strictly dependent on accessory cell function. Because accessory cells are a potent source of IL 1 and given that IL 1 has been shown in some instances to replace the requirement for accessory cells in T cell activation, it was of interest to directly compare the level of IL 1 receptor (IL 1-R) 1 expression by L3T4 + and Lyt-2 + T cells. In this study we show with the use of a direct IL 1-binding assay, that detectable IL 1-R expression is restricted to the L3T4 + subset.