Lung
surfactant protein D (
SP-D) is a
carbohydrate pattern recognition immune molecule. It can interact with a range of pathogens, stimulate immune cells and manipulate
cytokine profiles during host's immune response.
SP-D has also been shown to interact, via its
carbohydrate recognition domains, with
glycoprotein allergens of house dust mite (Dermatophagoides pteronyssinus, Derp), inhibiting specific
IgE isolated from mite-sensitive asthmatic patients from binding these
allergens, and blocking subsequent histamine release from sensitized basophils. In the present study, we have examined the protection offered by various doses of
intranasal administration of a recombinant fragment of human
SP-D (rhSP-D) in a murine model of pulmonary
hypersensitivity to Derp
allergens which showed characteristic high levels of specific
IgE antibodies, peripheral blood
eosinophilia, pulmonary infiltrates and a Th2
cytokine response. Treatment of Derp mice with rhSP-D led to significant reduction in Derp-specific
IgE levels, blood
eosinophilia and pulmonary cellular infiltration. The levels of
IL-4 and
IL-5 were decreased, while those of
IL-12 and IFN-gamma were raised in the supernatant of the cultured splenocytes, indicating a Th2 to Th1 polarization. These results suggest that
SP-D has a protective role in the modulation of allergic sensitization and in the development of
allergic reactions to Derp
allergens and highlight potential of the rhSP-D as a therapeutic for pulmonary
hypersensitivity.