Epstein-Barr virus-containing epithelial cells from nasopharyngeal carcinoma produce interleukin 1 alpha

Nasopharyngeal carcinoma (NPC) is a human epithelial cancer that is constantly associated with the Epstein-Barr virus (EBV). Investigations on this tumor have been limited so far by the difficulty of culturing NPC cells for long periods. C15 is an NPC tumor that has been successfully carried in nude mice for greater than 2 yr. C15 cells isolated from the animal were shown to produce a soluble factor with interleukin 1 (IL-1) activity. Its biochemical (Mr, approximately equal to 17,000; pI approximately equal to 5) and immunological properties are identical to those of IL-1 alpha. RNA gel blot analysis showed IL-1 alpha, but not IL-1 beta, transcripts in C15 cells, in sharp contrast to monocytes that express IL-1 beta predominantly. Media from short-term cultures of fresh NPC biopsies also contained a strong IL-1 activity. Several lymphoblastoid cell lines obtained by EBV infection of normal B lymphocytes have been shown to produce IL-1 and use it as an autocrine growth factor. The production of IL-1 by malignant EBV-containing epithelial cells indicates that different types of EBV-infected cells produce IL-1. A relationship might exist between EBV and constitutive production of IL-1. The IL-1 produced by the malignant epithelial cells in vivo could stimulate the development of the pronounced T-cell infiltrate observed in NPC tumors.