[Function, molecular structure and gene expression regulation of interleukin 9 (IL-9)]

Abstract

Interleukin-9 (IL-9)/P40 is a recently reported murine growth factor for helper T-cell clones. It is produced by ConA stimulated CD4+ T-cells or several T-cell lines such as TUC 2.15 derived from C57Bl/6 mouse. In the murine system, IL-9/P40 directly supported proliferation of mucosal type mast cells, and also induced erythroid burst formation, indirectly. On the other hand, human IL-9, which is a homologue to murine P40, was cloned from a cDNA library prepared with mRNA isolated from PHA-induced T-cell line (C5MJ2). Analysis of the sequence of cDNA revealed a striking similarity between murine and human IL-9/P40. Human IL-9 supported formation of a subpopulation of erythroid bursts that are responsive to IL-3. In this communication, identification, cloning of cDNA, and biological activities of murine and human IL-9/P40 are discussed.