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Allergen-induced bronchial inflammation is associated with decreased levels of surfactant proteins A and D in a murine model of asthma

Authors


Jiu-Yao Wang, Division of Clinical Immunology, Department of Paediatrics, National Cheng Kung University Medical Center, No.138, Sheng-Li Road, Tainan 70428, Taiwan, Republic of China. E-mail: a122@mail.ncku.edu.tw

Abstract

Background Increasing evidence suggests that pulmonary surfactant protein A (SP-A) and D (SP-D) participate in the lung defence against pathogens. However, the role of surfactant proteins in the pathogenesis of allergen-induced airway inflammation has not been elucidated. In this study we examined the levels and distributions of SP-A and SP-D in a dust mite (Dermatophagoides pteronyssinus, Der p) allergen-induced murine model of asthma.

Methods The concentration of SP-A and SP-D in the bronchoalveolar lavage fluid (BALF) and the distribution of surfactant proteins in the lung were assayed by ELISA and immunohistochemistry methods, respectively. The effect of surfactant proteins on allergen-induced pulmonary lymphocyte proliferation was also studied.

Results We demonstrated that there were marked reductions of SP-A and SP-D levels in the BALF of Der p-sensitized BALB/c mice at 48–72 h after allergen challenge (AC). Both purified SP-A and SP-D were able to suppress, in a dose dependent manner, Der p-stimulated intrapulmonary lymphocyte proliferation of naïve mice with saline or allergen challenge, or of Der p-sensitized mice with saline challenge. On the contrary, this suppressive effect was mild (< 9%) on lymphocytes from sensitized mice after AC.

Conclusion These results indicated the involvement of pulmonary surfactant proteins in the allergic bronchial inflammation of sensitized mice.

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