Bird droppings contain endotoxin and (1-->3)-beta-D-glucan

Pulmonary Exposure to 1→3-β-Glucan Alters Adaptive Immune Responses in Rats

1 --> 3-beta-glucans have been associated with increased pulmonary inflammation in fungal-related indoor air problems. Epidemiological studies have shown a correlation between increases in T-cell proliferation and decreases in CD4+/CD8+ ratio after exposure to fungi. The objective of the present investigation was to determine the mechanisms by which 1 --> 3-beta-glucans affect immune responses using an animal model. Rats received a single dose of zymosan A (2.5 mg/kg body weight) via intratracheal instillation (IT) and were euthanized on days 1, 4, 6, 8, and 10 post IT. Bronchoalveolar lavage was performed at each time point post-IT. Inflammation and lung injury were assessed by measuring neutrophil infiltration into bronchoalveolar lavage fluid (BALF) and by measuring albumin and lactate dehydrogenase levels in BALF, respectively. Alveolar macrophage activation was determined by chemiluminescence. Immune response was characterized via immunophenotyping of bronchoalveolar lavage cells and lymphocytes isolated from the lung-associated lymph nodes. Upon challenge with zymosan, rats exhibited increased inflammation and injury at early time points (days 1 and 4) post IT exposure. Although elevations in neutrophil infiltration and chemiluminescence had returned to control levels on day 4, lymphocytes recovered from lung-associated lymph nodes continued to proliferate and reached a maximum on day 6. The CD4+/CD8+ T cell ratio from lymph nodes was lower in zymosan-treated rats than in control rats. Zymosan treatment increased tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10, and IL-12p70 secretion in BALF on day 1. In summary, rats exposed to zymosan had an increase in acute inflammation, and the altered lymphocyte profiles were consistent with the findings of epidemiology studies.

Extrinsic allergic alveolitis

Extrinsic allergic alveolitis (also known as hypersensitivity pneumonitis) is caused by repeated inhalation of mainly organic antigens by sensitized subjects. This induces a hypersensitivity response in the distal bronchioles and alveoli and subjects may present clinically with a variety of symptoms. The aims of this review are to describe the current concepts of the immunological response, the diverse clinical presentation of this disease, the relevant investigations and management, and areas for future studies.

Takes your breath away--the immunology of allergic alveolitis

Extrinsic allergic alveolitis (synonym: hypersensitivity pneumonitis) is caused by inhaling antigenic aerosols which induce hypersensitivity responses in susceptible individuals. It is an interstitial inflammatory disease affecting the distal, gas-exchanging parts of the lung, in contrast to allergic asthma where the inflammation is more proximal, affecting the conducting airways. The aims of this review are to describe current concepts of the immunology of this model of lung inflammation, to describe some of the constitutional and environmental characteristics which affect disease susceptibility and development, and to describe topics for prospective study.

Modified endotoxin responses in rats pretreated with 1-->3-beta-glucan (zymosan A)

The present study investigates whether 1-->3-beta-glucans (zymosan particles) modify the pulmonary response of rats to endotoxin (lipopolysaccharide, LPS). Initial experiments were conducted to establish appropriate doses of LPS and regimens for exposure to zymosan and LPS. Interaction between zymosan and LPS exposures was determined to be the deviation from the sum of the individual effects of these agents. Treatment with zymosan on Day 1 and LPS on Day 2 modified several indices of pulmonary responsiveness, including tumor necrosis factor-alpha, albumin, and lactate dehydrogenase activity (LDH) in first acellular lavage fluid as well as the levels of chemiluminescence (CL), NO-dependent CL, and nitric oxide production in cultured lavaged alveolar macrophage cells determined 1 day after exposure. No significant deviation from additivity was found for breathing rate increase and polymorphonuclear leukocytes infiltration. Simultaneous administration of zymosan and LPS or administration of LPS before zymosan did not change these indices of pulmonary responsiveness. These data suggest that the inhibitory effect of 1-->3-beta-glucans on pulmonary responsiveness to endotoxin exposure was apparent only when rats were pretreated with 1-->3-beta-glucan. These results suggest that complex interaction of components may exist in exposure to organic dusts. Therefore, hazard may not be defined by measuring endotoxin or 1-->3-beta-glucans alone.