Interaction between Peripheral Blood Immune Cells and Activated Respiratory Epithelial Cells with Airborne Fungi

Shin, Seung Heon; Lim, Geun Hye; Kim, Dong Hoon

Abstract

BACKGROUND AND OBJECTIVES: Fungi are ubiquitous in the environment and their products may contribute to the development and exacerbation of airway diseases. The respiratory epithelium is the first barrier encountered by airborne allergens and an active participant in airway inflammation. During inflammatory reaction, many inflammatory cells are recruited to tissue from circulation, and they are located in close proximity to the epithelium. In this study, we hypothesized that respiratory epithelial cells and immune cells would interact and fungi could enhance their inflammatory reactions. MATERIALS AND METHOD: BEAS-2B was stimulated with airborne fungi (Alternaria, Aspergillus, Cladosporium, etc) for 24 hours, and then co-cultured with peripheral blood mononuclear cells (PBMCs), CD4+ lymphocytes, natural killer (NK) cells, and monocytes for 3 to 5 days. Interleukin-6 (IL-6), IL-1beta, granulocyte- macrophage colony stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-alpha) were measured to determine the activation of immune cells. Transwell insert system was used to determine the importance of physical contact between epithelial cells and immune cells.
RESULTS
Fungi, especially Alternaria, enhanced the production of chemical mediators from respiratory epithelial cells. When epithelial cells were co-cultured with immune cells, supernatants contained larger amounts of chemical mediators than when epithelial cells were cultured alone. When co-cultured with activated epithelial cells, TNF-alpha production was significantly increased by PBMCs, and physical contact was needed to interact between epithelial cells and PBMCs.
CONCLUSION
This study suggests that fungi enhances the immune reaction between respiratory epithelial cells and peripheral blood immune cells, and the physical contact between epithelial cells and immune cells is needed to enhance the production of cytokines.