Early stages ofAscaris suuminduce airway inflammation andhyperreactivity in a mouse model

ABSTRACT

The inflammatory and functional changes that occur in murinelung after infection with 2500 infectiveAscaris suumeggswere studied in this work. A sequential influx of neutrophils,mononuclear cells and eosinophils occurred into airwaysconcomitantly with migration of larvae from liver to thelungs. Histological analysis of the lung showed a severe intraalveolarhaemorrhage at the peak of larval migration (day 8)and the most intense inflammatory cell infiltrate on day 14.AscarisL3 were found in alveolar spaces and inside bronchioleson day 8. The number of eosinophils was elevated inthe blood on days 8 and 14. The peak of eosinophil influx intothe lung was at day 14, as indicated by the high levels of eosinophilperoxidase activity, followed by their migration into theairways. The antibody response against egg and larval antigensconsisted mainly of IgG1 and IgM, and also of IgE andanaphylactic IgG1, that cross-reacted with adult worm antigens.Total IgE levels were substantially elevated during theinfection. Measurement of lung mechanical parametersshowed airway hyperreactivity in infected mice. In conclusion,the murine model ofA. suuminfection mimics the Th2-induced parameters observed in pigs and humans and can beused to analyse the immunoregulatory properties of thishelminth.