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The effects of poly I:C stimulation of primary bronchial epithelial cells and TSLP secretion on CD34+ progenitor cell eosinophil and basophil differentiation


In asthmatic lungs, elevated levels of thymic stromal lymphopoetin (TSLP) are linked to eosinophilic inflammation and disease severity [1]. TSLP is involved in initiating a TH2 inflammatory response, through activation of T cells, and recently, CD34+ hemopoietic progenitor cells [2, 3]. However, the biological effects of epithelial-derived TSLP on human peripheral blood (PB) CD34+ progenitor eosinophil-basophil (Eo/B) lineage commitment have not been described. The aim of the current study is to examine the effects of primary bronchial epithelial cell-derived TSLP on CD34+ hemopoietic progenitor differentiation.


Primary bronchial epithelial cells (PBEC) grown in air-liquid interface were apically stimulated with media or varying doses of polyinosinic:polycytidylic acid (Poly I:C; 1, 10, 25, and 50g/mL) and cultured in the presence or absence of PB CD34+ cells in the basolateral compartment overnight. Supernatant was collected and analyzed for cytokine/chemokine secretion using Luminex assays. Overnight co-cultured PB CD34+ cells were (1) cultured in methylcellulose colony assays to assess for the mean numbers of Eo/B colony-forming units (CFU) (colonies were defined as ≥ 40 cells) after 14 d; or (2) assessed for TSLPR expression using flow cytometry.


Preliminary data demonstrates that overnight stimulation of PBEC with poly I:C in the absence of PB CD34+ cells induced a dose-dependent release of IL-4, IL-5, IL-13, TNF eotaxin-1, and MCP-1; however, failed to secrete detectible levels of IL-1β and IFN-. Poly I:C at 10µg/mL enhanced TSLP and TARC secretion while at 50µg/mL, poly I:C enhanced IL-33 secretion from PBEC compared to unstimulated control. Furthermore, basal levels of IL-3, IL-6, IL-8, MDC, and RANTES were detected from rested PBEC, with no observable trend in secretion following poly I:C stimulation. Finally, PB CD34+ cells co-cultured overnight with poly I:C-stimulated PBEC have been cultured in methylcellulose colony assays and waiting for Eo/B CFU to be counted.


In conclusion, our co-culture system will allow for the establishment of epithelial-derived TSLP activity and its influence on CD34+ progenitor Eo/B differentiation. In the future, we would like to examine whether PBEC obtained from atopic vs. non-atopic individuals results in distinct progenitor response.


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I would like to thank the AllerGen Network for the AllerGen Summer Studentship, and the members of the Denburg lab.

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Correspondence to Ashley Yu.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

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Yu, A., Hui, C.C. & Denburg, J.A. The effects of poly I:C stimulation of primary bronchial epithelial cells and TSLP secretion on CD34+ progenitor cell eosinophil and basophil differentiation. All Asth Clin Immun 10, A47 (2014).

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  • Peripheral Blood CD34
  • Basolateral Compartment
  • Luminex Assay
  • Polycytidylic Acid
  • Hemopoietic Progenitor