Anna-Liisa Pasanen

Slight respiratory irritation but not inflammation in mice exposed to (1-->3)-beta-D-glucan aerosols.

Airway irritation effects after single and repeated inhalation exposures to aerosols of beta-glucan (grifolan) were investigated in mice. In addition, the effects on serum total immunoglobulin E (IgE) production and histopathological inflammation in the respiratory tract were studied. The beta-glucan aerosols provoked slight sensory irritation in the airways, but the response was not concentration dependent at the levels studied. Slight pulmonary irritation was observed after repeated exposures. No effect was found on the serum total IgE levels, and no signs of inflammation were seen in the airways 6 h after the final exposure. The results suggest that, irrespective of previous fungal sensitization of the animals, inhaled beta-glucan may cause symptoms of respiratory tract irritation but without apparent inflammation. Respiratory tract irritation reported after inhalation of fungi may not be entirely attributed to beta-glucan.

Effects of aerosols from nontoxic Stachybotrys chartarum on murine airways

Acute effects on the upper and lower respiratory tract due to inhalation exposure to Stachybotrys chartarum (Sc) extract were investigated in mice. In addition, the capacity of the Sc exposure to activate immune system and cause inflammation in the respiratory tract was studied. The inhalation of Sc extract aerosols was observed to provoke sensory irritation in the airways of both naive and Sc -immunized mice. In contrast, exposure to aerosolized ovalbumin or phosphate buffered saline did not cause this effect. Exposure to Sc twice a week for 3 wk increased significantly the serum total immunoglobulin E (IgE) levels in BALB/ c mice immunized with Sc as well as in nonimmunized mice. A slight presence of inflammatory cells was observed in the alveoli 3 days after the last exposure to Sc. In conclusion, Sc extract has the capacity to provoke sensory irritation in the murine airways and to activate the murine immune system.

Partial amino acid sequence of a cellulase-like component with IgE-binding properties from Stachybotrys chartarum

Background: The aim of this study was to characterize the amino acid sequence of a selected Stachybotrys chartarum component and to investigate human IgE reactivity against components of S. chartarum and nine other fungal species. Methods: Human IgE reactivity against S. chartarum and nine other fungal extracts was investigated by the immunoblotting method. For automated amino acid sequencing analyses, the S. chartarum extract was purified by ion exchange chromatography prior to in-gel alkylation and digestion with modified trypsin. Results: Human IgE reactivity was detected against eight components in the S. chartarum extract. Over 80% of the sera from the exposed subjects and less than 50% of the control sera recognized the 33-, 48- and 50-kD S. chartarum components. The human sera detected a 48- to 50-kD component from the extracts of eight fungal species. Nineteen peptide sequences were identified from the 48-kD component of S. chartarum. An analysis of the peptide sequences revealed homology with known fungal glycoside hydrolase enzymes (cellulases). Conclusions: The data showed human IgE reactivity against several S. chartarum components, including one at 48 kD. On the other hand, the human sera recognized 48- to 50-kD components from seven other fungal species, suggesting shared antigenic components (e.g. enolase) between the fungi. Thus, to our knowledge, this is the first antigen identified from S. chartarum.

The Effects of Wood Dusts on the Redox Status and Cell Death in Mouse Macrophages (Raw 264.7) and Human Leukocytes in Vitro

Wood dusts are classified as carcinogenic to humans and also produce other toxic, allergic, and acute effects in woodworkers. However, little is known about causative agents in wood dusts and their mechanisms of action. The effects of different tree species and particle size for biological activity were studied. The differences in the production of reactive oxygen species (ROS) and cell death (necrotic and apoptotic) between mouse macrophage (RAW 264.7) cells and human polymorphonuclear leukocytes (PMNL) for pine, birch, and beech dust exposures were investigated in vitro. The pine and birch dust exposure (1-100 w g/ml) produced concentration-dependent ROS production in both the cells, which was one order of magnitude higher with pine dust. The ROS production was faster in human PNML than murine RAW cells. The higher concentrations (500 and/or 1000 w g/ml) decreased ROS formation. With pine and birch dust exposure, this was probably due to the necrotic cell death. The pine dust concentrations of 500 and 1000 w g/ml were cytotoxic to human PMNL. The beech dust exposure activated the ROS production and decreased the cell viability only at the highest concentrations, being least potent of the three dusts. A sign of the apoptotic cell death in the murine RAW cells was observed at the pine dust concentration of 100 w g/ml. The exposure to the birch and beech dusts with a smaller particle size (<5 w m) produced greater ROS production than exposure to the corresponding dust with a wide range of particle sizes. However, changing the particle size did not affect the cell viability. The results indicate that the type of wood dust (tree species and possibly particle size) has a significant impact on the function and viability of phagocytic cells.