A Triple Co-Culture Model of the Human Respiratory Tract to Study Immune-Modulatory Effects of Liposomes and Virosomes.

Rebecca A M Blom,Olivier Schaerer,Christophe Von Garnier,Mario Amacker,Sean R R Hall,Fabian Blank,R Maarten Van Dijk,Kristína Krempaská,Christian Moser,Silvia T Erni

doi:10.1371/journal.pone.0163539

Abstract

The respiratory tract with its ease of access, vast surface area and dense network of antigen-presenting cells (APCs) represents an ideal target for immune-modulation. Bio-mimetic nanocarriers such as virosomes may provide immunomodulatory properties to treat diseases such as allergic asthma. In our study we employed a triple co-culture model of epithelial cells, macrophages and dendritic cells to simulate the human airway barrier. The epithelial cell line 16HBE was grown on inserts and supplemented with human blood monocyte-derived macrophages (MDMs) and dendritic cells (MDDCs) for exposure to influenza virosomes and liposomes. Additionally, primary human nasal epithelial cells (PHNEC) and EpCAM+ epithelial progenitor cell mono-cultures were utilized to simulate epithelium from large and smaller airways, respectively. To assess particle uptake and phenotype change, cell cultures were analyzed by flow cytometry and pro-inflammatory cytokine concentrations were measured by ELISA. All cell types internalized virosomes more efficiently than liposomes in both mono- and co-cultures. APCs like MDMs and MDDCs showed the highest uptake capacity. Virosome and liposome treatment caused a moderate degree of activation in MDDCs from mono-cultures and induced an increased cytokine production in co-cultures. In epithelial cells, virosome uptake was increased compared to liposomes in both mono- and co-cultures with EpCAM+ epithelial progenitor cells showing highest uptake capacity. In conclusion, all cell types successfully internalized both nanocarriers with virosomes being taken up by a higher proportion of cells and at a higher rate inducing limited activation of MDDCs. Thus virosomes may represent ideal carrier antigen systems to modulate mucosal immune responses in the respiratory tract without causing excessive inflammatory changes.

Highlights

With its ease of access, the vast surface area and extended network of dendritic cells (DCs), the respiratory tract represents a promising target for inhaled immune-modulatory approaches by bio-mimetic nanocarriers such as virosomes and liposomes [1]
Particle size was measured by dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) that routinely provided a hydrodynamic diameter of 90–96 nm, and particle sizes of 84–86 nm for all nanocarrier formulations respectively (Table 1)
We investigated whether treatment virosomes or liposomes induce monocyte-derived macrophages (MDMs), monocyte-derived DCs (MDDCs) and 16HBE phenotype changes or activation by expression of co-stimulatory surface molecules in both mono- and co-cultures

Summary

Introduction

With its ease of access, the vast surface area and extended network of dendritic cells (DCs), the respiratory tract represents a promising target for inhaled immune-modulatory approaches by bio-mimetic nanocarriers such as virosomes and liposomes [1]. DCs have the ability to migrate to draining lymph nodes where they stimulate antigen specific proliferation of naïve T-lymphocytes and their differentiation into effector T cells [5]. This provides an important role in allergic airway diseases such as allergic asthma, which is frequently characterized by a skewed Th2 cell response

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