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Updated: Apr 27, 2026
Murine Model of Allergen Induced Asthma
Published on: May 14, 2012
Assessing the allergenic potential of molds found in water-damaged homes in a mouse model
Marsha D W Ward1, Lisa B Copeland, James Lehmann
1National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency , Research Triangle Park, NC , USA and.
Abstract:
Damp/moldy indoor environments, which have resulted from flooding events and may increase as a result of climate change, have been associated with asthma exacerbation. Certain molds found in significantly higher or lower concentrations in asthmatics' homes compared to control homes have been categorized as Group 1 (G1) and Group 2 (G2) molds, respectively. We have compared the allergic potential of selected G1/G2 molds to house dust mite (HDM) in a mouse model. BALB/c mice were exposed to mold (0-80 µg) or HDM (20 µg) extract by intratracheal aspiration either 4X over 4 weeks (allergenicity) or 1X (non-specific responses). Airflow limitation (methacholine challenge) was measured (Day 1) and serum and bronchoalveolar lavage fluid were collected (Day 2) after the final exposure. The G1 molds induced low-to-moderate responses and required higher doses to achieve antigen-specific IgE results similar to those induced by HDM. Compared to HDM responses, the G2 mold in this study required lower doses to induce a similar response. Acute exposure responses suggest some molds may exacerbate asthmatic responses. These studies demonstrate the differing capacities of molds to induce responses associated with allergic asthma, including differences in the threshold dose for allergy induction. Therefore, molds must be evaluated individually for allergic/asthmatic potential. These studies along with our previous studies with G1 (Stachybotrys chartarum)/G2 (Penicillium chrysogenum) molds suggest that the G1/G2 categorization is not indicative of allergic potential but they do not preclude this categorization's utility in determining unhealthy building dampness.
Insights
Damp indoor environments can worsen asthma. This study found that different mold groups (G1 and G2) have varying allergic potentials compared to house dust mites, indicating individual mold assessment is crucial.
Area of Science:
- Environmental Health
- Allergology
- Toxicology
Background:
- Damp and moldy indoor environments are linked to asthma exacerbation.
- Molds are categorized into Group 1 (G1) and Group 2 (G2) based on concentrations in asthmatics' homes.
- Climate change may increase the prevalence of damp indoor environments.
Purpose of the Study:
- To compare the allergic potential of selected G1 and G2 molds against house dust mite (HDM).
- To evaluate mold-induced allergic responses in a mouse model.
Main Methods:
- BALB/c mice were intratracheally instilled with mold or HDM extract.
- Allergenicity was assessed via repeated exposure (4X over 4 weeks), and non-specific responses via single exposure (1X).
- Airflow limitation, serum, and bronchoalveolar lavage fluid were analyzed post-exposure.
Main Results:
- G1 molds induced low-to-moderate allergic responses, requiring higher doses than HDM for similar IgE levels.
- G2 molds induced responses comparable to HDM at lower doses.
- Acute mold exposure suggested potential for asthma exacerbation.
Conclusions:
- Molds exhibit differing capacities to induce allergic asthma responses.
- The threshold dose for allergy induction varies among molds.
- Individual mold assessment is necessary to determine allergic/asthmatic potential, as G1/G2 categorization alone is insufficient.
- G1/G2 categorization may still be useful for identifying unhealthy building dampness.
