Abstract
Aspergillus fumigatus is an important opportunistic fungal pathogen. Patients treated with chemotherapeutic agent such as cyclophosphamide are susceptible to invasive pulmonary aspergillosis. Dectin-1 is a pattern recognition receptor critically involved in immune responses to A. fumigatus. Therefore, we tested whether cyclophosphamide treatment could cause alterations in dectin-1 expression in the lung, which could contribute to invasive pulmonary Aspergillus infections in patients. We established a murine A. fumigatus infectious model to investigate the kinetics of dectin-1 expression in lung tissues in the presence or absence of cyclophosphamide treatment. During infection, dectin-1 expression was strikingly increased in immunocompetent mice infected with A. fumigatus as compared to those in a non-infected control group. In vitro macrophages stimulated with heat-inactivated A. fumigatus conidia expressed a significantly elevated level of dectin-1. Infected mice treated with cyclophosphamide showed decreased levels of dectin-1 and a higher fungal burden in the lung than the infected mice without cyclophosphamide treatment. These results suggest that dectin-1 is involved in host defense against A. fumigatus infection and that suppression of dectin-1 expression caused by cyclophosphamide may contribute to susceptibility to infections caused by this fungus in the immunocompromised host.
Acknowledgements
We thank Prof. Zhi Liu and Ms. Lisa Heimbach (University of North Carolina at Chapel Hill, USA) for their critical reading and editing of the manuscript. This project was supported by Specialized Research Fund for the Doctoral Program of Higher Education of China, Ministry of Education.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
This paper was first published online on Early Online on 01 February 2010.