Production of interleukin 1 alpha by a trichilemmoma cell line.

In order to obtain a good source of human epidermal cell derived thymocyte activating factor (ETAF) for biological study, several cell lines of epidermal origin were cultured. One of the trichilemmoma cell lines, KTL-1, was found to produce ETAF satisfactorily in its culture supernatant. The culture supernatant was collected and analyzed to determine the nature of the ETAF activity. The ETAF activity was completely inhibited by anti-IL 1 alpha antibody, but not by anti-IL 1 beta antibody. Messenger RNA expression by KTL-1 cells was analyzed by using cDNA of IL 1 alpha as a probe. Messenger RNA was not detected in KTL-1 cells by either dot blot analysis or northern blot analysis. However, it was expressed weakly in the cytoplasm by in situ hybridization technique. Messenger RNA expression was easily detected in KTL-1 cells stimulated by lipopolysaccharide (LPS). Messenger RNA expression reached a peak at 3 hours after stimulation of LPS. A trichilemmoma cell line, KTL-1, can be a good source of human ETAF for biological study.