The relative allergenicity of Stachybotrys chartarum compared to house dust mite extracts in a mouse model

Abstract

A report by the Institute of Medicine suggested that more research is needed to better understand mold effects on allergic disease, particularly asthma development. The authors compared the ability of the fungus Stachybotrys chartarum (SCE) and house dust mite (HDM) extracts to induce allergic responses in BALB/c mice. The extracts were administered by intratracheal aspiration (IA) at several doses (0, 2.5, 5, 10, 20, 40, and 80 µg) 4 times over a 4-week period. Three days after the last IA exposure, serum and bronchoalveolar lavage fluid (BALF) were collected. The relative allergenicity of the extracts was evaluated based on the lowest dose that induced a significant response compared to control (0 μg) and the linear regression slope analysis across the dose range. SCE induced a more robust response than HDM for BALF some inflammatory cells (macrophage and neutrophils), whereas HDM induced more robust BALF lymphocyte and eosinophil responses. Although SCE induced a more robust serum total immunoglobulin E (IgE) response than did HDM, the induction of a similar response in a functional, antigen-specific IgE assay required approximately twice as much SCE as HDM. Even though SCE demonstrates the ability to induce allergic responses in the mouse model, considering the importance and relevance of eosinophil, lymphocyte, and antigen-specific IgE in allergic airway disease, it is concluded that HDM is more potent than SCE in the induction of allergic responses. These data suggest a threshold dose for SCE allergy induction. Furthermore, in damp water-damaged environments, exposure to S. chartarum might easily exceed the sensitization threshold for a susceptible population.

Keywords::

• Allergy
• house dust mite
• mold
• mouse model
• Stachybotrys chartarum

Acknowledgements

The authors would like to thank Debora Andrews, Elizabeth Boykin, and Judy Richards of US EPA for expert technical assistance. Additionally, the authors would like to thank Drs. Timothy Dean and Cherie Pucheu-Haston for their review of the manuscript.

Declaration of interest

The US Environmental Protection Agency through its Office of Research and Development funded and managed the research described in this paper. It has been reviewed in accordance with the Agency’s peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.