Murine allergic respiratory responses to the major house dust mite allergen Der p 1

Background Although many studies have examined chronic asthma, limited data exist on acute immunopathogenic events induced by allergens. The aim of th e study was to investigate the acute cellular, serologic and histopathologi c events in airway inflammation produced by intranasal challenge of mice se nsitised to the major house dust mite allergen Der p 1. Methods: C57BL/6 mi ce were immunised subcutaneously with Der p 1 in alum. Mice were bled and c hallenged intranasally with Der p 1 on day 14 and killed on day 17. Lungs w ere fixed in situ, processed and stained with haematoxylin and eosin. The d egree of inflammation and eosinophil infiltration was quantified by image a nalysis. Specific IgE was determined by passive cutaneous anaphylaxis. Cell s from spleen and draining lymph nodes were cultured for 24 h with Der p 1, and IL-3/GM-CSF released into supernatants was measured by bioassay. Resul ts: Intranasal challenge of sensitised mice induced eosinophilic influx int o the large and small airways and the alveolar regions of the lung, mucus p lugging and in severe cases numerous Charcot-Leyden crystals. The quantitat ion of the inflammation induced by different sensitisation and challenge do ses showed that optimal inflammation could be produced using only 1 mu g of allergen for both sensitisation and challenge. The degree of inflammation was not related to the titre of IgE antibody and was indeed produced in its absence. T cell reactivity of spleen cells to the allergen was decreased s uggesting cell migration or inactivation. Conclusions: Mice sensitised and challenged intranasally with as little as 1 mu g of Der p 1 produced an ext ensive pulmonary eosinophilic inflammation which shared many of the feature s of the inflammation found in asthma. The small amount of allergens requir ed and the use of intranasal challenge should provide a useful model.