Enhanced response to pulmonary Streptococcus pneumoniae infection is associated with primary ciliary dyskinesia in mice lacking Pcdp1 and Spef2
Lower airway abnormalities are common in patients with primary ciliary dyskinesia (PCD), a pediatric syndrome that results from structural or functional defects in motile cilia. Patients can suffer from recurrent bacterial infection in the lung, bronchiectasis, and respiratory distress in addition to chronic sinusitis, otitis media, infertility, and laterality defects. However, surprisingly little is known about the pulmonary phenotype of mouse models of this disorder. The pulmonary phenotype of two mouse models of PCD, nm1054 and bgh, which lack Pcdp1 and Spef2, respectively, was investigated by histological and immunohistochemical analysis. In addition, both models were challenged with Streptococcus pneumoniae, a common respiratory pathogen found in the lungs of PCD patients. Histopathological analyses reveal no detectable cellular, developmental, or inflammatory abnormalities in the lower airway of either PCD model. However, exposure to S. pneumoniae results in a markedly enhanced inflammatory response in both models. Based on analysis of inflammatory cells in bronchoalveolar lavage fluid and flow cytometric analysis of cytokines in the lung, the bgh model shows a particularly dramatic lymphocytic response by 3 days post-infection compared to the nm1054 model or wild type animals. Defects in ciliary motility result in a severe response to pulmonary infection. The PCD models nm1054 and bgh are distinct and clinically relevant models for future studies investigating the role of mucociliary clearance in host defense.