Production of Interleukin 1 (IL1) by Human Thymic Epithelial Cells (TEC)

Abstract

The thymic microenvironment plays a central role in T cell proliferation and maturation, both through the secretion of thymic hormones (1), and through direct interactions between T cell precursors and their stromal partners (2, 3). Thymic epithelial cells (TEC) are ideally suited, both anatomically and functionally, as microenvironmental cells able to differentiate and educate T cells. Our investigations regarding human TEC have shown that cultures of thymic epithelium are an interesting model for phenotypic and functional studies. We have shown that cultured TEC express keratin, produce extracellular matrix components (4), and secrete the thymic hormone, thymulin (5). As a part of our effort to understand the relationship between developing T lymphocytes and the epithelial microenvironment of the thymus, we have shown that TEC class II antigen expression is lost in culture and regulated by recombinant interferon-(6). Interleukin 1 (IL1) represents a family of polypeptide cytokines which mediate many aspects of the immune and inflamatory responses (reviewed in ref. 7). Although they were originally considered to be strictly the product of activated monocytes or macrophages, a number of recent reports have indicated that other cell types may produce ILl-like molecules (8-11).