Email updates

Keep up to date with the latest news and content from Respiratory Research and BioMed Central.

Open Access Research

Human leukocyte antigen-G expression in differentiated human airway epithelial cells: lack of modulation by Th2-associated cytokines

Steven R White12*, Dagan A Loisel3, Randi Stern2, Bharathi Laxman2, Timothy Floreth2 and Bertha A Marroquin2

Author Affiliations

1 University of Chicago, Section of Pulmonary and Critical Care Medicine, 5841 S. Maryland Ave, MC 6076, Chicago, IL 60637, USA

2 From the Departments of Medicine and Human Genetics, Chicago, IL 60637, USA

3 Human Genetics, University of Chicago, Chicago, IL 60637, USA

For all author emails, please log on.

Respiratory Research 2013, 14:4  doi:10.1186/1465-9921-14-4

Published: 18 January 2013

Abstract

Background

Human leukocyte antigen (HLA)-G is a nonclassical class I antigen with immunomodulatory roles including up-regulation of suppressor T regulatory lymphocytes. HLA-G was recently identified as an asthma susceptibility gene, and expression of a soluble isoform, HLA-G5, has been demonstrated in human airway epithelium. Increased presence of HLA-G5 has been demonstrated in bronchoalveolar lavage fluid recovered from patients with mild asthma; this suggests a role for this isoform in modulating airway inflammation though the mechanisms by which this occurs is unclear. Airway inflammation associated with Th2 cytokines such as IL-4 and IL-13 is a principal feature of asthma, but whether these cytokines elicit expression of HLA-G is not known.

Methods

We examined gene and protein expression of both soluble (G5) and membrane-bound (G1) HLA-G isoforms in primary differentiated human airway epithelial cells collected from normal lungs and grown in air-liquid interface culture. Cells were treated with up to 10 ng/ml of either IL-4, IL-5, or IL-13, or 100 ng/ml of the immunomodulatory cytokine IL-10, or 10,000 U/ml of the Th1-associated cytokine interferon-beta, for 24 hr, after which RNA was isolated for evaluation by quantitative PCR and protein was collected for Western blot analysis.

Results

HLA-G5 but not G1 was present in dAEC as demonstrated by quantitative PCR, western blot and confocal microscopy. Neither G5 nor G1 expression was increased by the Th2-associated cytokines IL-4, IL-5 or IL-13 over 24 hr, nor after treatment with IL-10, but was increased 4.5 ± 1.4 fold after treatment with 10,000 U/ml interferon-beta.

Conclusions

These data demonstrate the constitutive expression of a T lymphocyte regulatory molecule in differentiated human airway epithelial cells that is not modulated by Th2-associated cytokines.

Keywords:
HLA-G; Airway epithelium; IL-13; IL-4; IL-5; IL-10; Asthma