Synthesis and secretion of interleukin-15 by freshly isolated human bronchial epithelial cells.
BACKGROUND
Interleukin-15 (IL-15), which shares many functional activities of IL-2, is proposed as a potential modulator of T and natural killer (NK) cell-mediated inflammatory diseases. Since IL-15 gene is expressed in various cell types including epithelial cells, we examined how proinflammatory modulators affect IL-15 gene expression in both freshly isolated human bronchial epithelial cells (HBECs) and the human bronchial epithelial cell line BEAS-2B.


METHODS
HBECs were obtained from 25 patients with primary lung cancer by bronchial brushing under bronchofiberscopy. The expressions of IL-15 and its receptor were examined using reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis and enzyme-linked immunosorbent assay.


RESULTS
IL-15 mRNA was constitutively expressed in the cells and was upregulated by several proinflammatory cytokines such as IL-1beta, tumor necrosis factor-alpha, interferon-gamma (IFN-gamma) and lipopolysaccharide. In addition, IFN-gamma but not other cytokines induced the synthesis and secretion of IL-15 protein. Investigation of IL-15 receptor expression using RT-PCR showed that IL-15Ralpha and IL-2Rbeta chains but not IL-2Ralpha or gamma chain were constitutively expressed in these cells.


CONCLUSIONS
Bronchial epithelial cells may contribute to T and NK cell-mediated airway inflammation through IL-15 production.
Department of Internal Medicine and Molecular Therapeutics, Course of Medical Oncology, University of Tokushima School of Medicine, Tokushima, Japan.
Ning
N
Ge
Yasuhiko
Y
Nishioka
Yoichi
Y
Nakamura
Yoshio
Y
Okano
Kazuo
K
Yoneda
Hirohisa
H
Ogawa
Akemi
A
Sugita
Hiroaki
H
Yanagawa
Saburo
S
Sone
D015152:Blotting, Northern; D001980:Bronchi / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D003609:Dactinomycin / Q000494:pharmacology; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology*; D007375:Interleukin-1 / Q000276:immunology / Q000494:pharmacology; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology
C508024:IL15RA protein, human; D007375:Interleukin-1; D019409:Interleukin-15; D008070:Lipopolysaccharides; D019384:Nucleic Acid Synthesis Inhibitors; D012333:RNA, Messenger; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D007371:Interferon-gamma