Journal Article

A Murine Inhalation Model to Characterize Pulmonary Exposure to Dry Aspergillus fumigatus Conidia

Buskirk, Amanda D., Templeton, Steven P., Hettick, Justin M., Germolec, Dori R., Beezhold, Donald H., Goldsmith, W. Travis, Green, Brett J., Lemons, Angela R., Anderson, Stacey E., Nayak, Ajay P., Kashon, Michael L.

2014

Overview

Most murine models of fungal exposure are based on the delivery of uncharacterized extracts or liquid conidia suspensions using aspiration or intranasal approaches. Studies that model exposure to dry fungal aerosols using whole body inhalation have only recently been described. In this study, we aimed to characterize pulmonary immune responses following repeated inhalation of conidia utilizing an acoustical generator to deliver dry fungal aerosols to mice housed in a nose only exposure chamber. Immunocompetent female BALB/cJ mice were exposed to conidia derived from Aspergillus fumigatus wild-type (WT) or a melanin-deficient (Δalb1) strain. Conidia were aerosolized and delivered to mice at an estimated deposition dose of 1×105 twice a week for 4 weeks (8 total). Histopathological and immunological endpoints were assessed 4, 24, 48, and 72 hours after the final exposure. Histopathological analysis showed that conidia derived from both strains induced lung inflammation, especially at 24 and 48 hour time points. Immunological endpoints evaluated in bronchoalveolar lavage fluid (BALF) and the mediastinal lymph nodes showed that exposure to WT conidia led to elevated numbers of macrophages, granulocytes, and lymphocytes. Importantly, CD8+ IL17+ (Tc17) cells were significantly higher in BALF and positively correlated with germination of A. fumigatus WT spores. Germination was associated with specific IgG to intracellular proteins while Δalb1 spores elicited antibodies to cell wall hydrophobin. These data suggest that inhalation exposures may provide a more representative analysis of immune responses following exposures to environmentally and occupationally prevalent fungal contaminants.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Acoustics / Administration, Inhalation / Aerosols / Allergies / Alveoli / Analysis / Animal models / Animals / Antibodies / Antibodies, Fungal - immunology / Antibody Formation - immunology / Antigens / Aspergillus fumigatus / Aspergillus fumigatus - immunology / Aspergillus fumigatus - physiology / Asthma / Biology and Life Sciences / Bronchoalveolar lavage / Bronchoalveolar Lavage Fluid - cytology / Bronchus / CD8 antigen / Cell Count / Cell Proliferation / Cell walls / Conidia / Contaminants / Cytokines - metabolism / Disease control / Disease Models, Animal / Disease prevention / Exposure / Female / Flow Cytometry / Fungi / Germination / Hyphae - physiology / Immune response / Immunoglobulin G / Immunoglobulin G - metabolism / Immunology / Inhalation / Inhalation Exposure / Interleukin 1 / Interleukin 17 / Laboratory animals / Leukocytes (granulocytic) / Lung - microbiology / Lung - pathology / Lungs / Lymph nodes / Lymph Nodes - pathology / Lymphocytes / Macrophages / Medicine and Health Sciences / Melanin / Mice / Mice, Inbred BALB C / Microorganisms / Nose / Oryza / Proteins / Proteomics / Research and Analysis Methods / Respiration / Species Specificity / Spores / Spores, Fungal - physiology / Toxicology