Intranasal delivery of a truncated recombinant human SP-D is effective at down-regulating allergic hypersensitivity in mice sensitized to allergens of Aspergillus fumigatus

Abstract

C57BL/6 mice were sensitized to Aspergillus fumigatus 1-week culture filtrate, which is rich in the non-glycosylated allergen Asp f1, a major allergen in allergic bronchopulmonary aspergillosis (ABPA). A comparison of the effect of treatment of allergen challenged mice by intranasal administration of a 60-kDa truncated recombinant form of human SP-D (rfhSP-D) or recombinant full length SP-A (rhSP-A) was undertaken. Treatment with rfhSP-D produced significant reduction in IgE, IgG1 and peripheral blood eosinophilia and treatment with rfhSP-D, but not rhSP-A resulted in a significant reduction in airway hyperresponsiveness as measured by whole body plethysmography. Lung histology revealed less peribronchial lymphocytic infiltration in mice treated with rfhSP-D. Intracellular cytokine staining of spleen homogenates showed increases in IL-12 and IFN-gamma and decrease in IL-4. The level of endogenous mouse SP-D was elevated sixfold in the lungs of sensitized mice and was not affected by treatment with rfhSP-D. Taken with our previous studies, with a BALB/c mouse model of ABPA using a 3-week A. fumigatus culture filtrate, the present results show that rfhSP-D can suppress the development of allergic symptoms in sensitized mice independent of genetic background and using a different preparation of A. fumigatus allergens.

Fig. 1

(a) Serum IgE and (b) Afu-specific IgG1 measured 3 days after treatment with five daily doses of 10 µg rfhSP-D or PBS given intranasally after intranasal challenge with Afu 1wcf and after re-challenge 1 week later with Afu alone. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, APrc = Afu re-challenged mice that had been treated with PBS, ARrc = Afu re-challenged mice that had been treated with rfhSP-D.

Fig. 2

Peripheral blood eosinophilia measured 1 day after treatment with four daily doses of 10 µg rfhSP-D or PBS given intranasally after intranasal challenge with Afu 1wcf and after re-challenge 1 week later with Afu alone. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, APrc = Afu re-challenged mice that had been treated with PBS, ARrc = Afu re-challenged mice that had been treated with rfhSP-D.

Fig. 3

Cytokines measured 1 day after treatment with two daily doses of 10 µg rfhSP-D given intranasally after intranasal challenge with Afu 1wcf. (a) IL-12 measured in the spleen, (b) IFN-γ measured in the spleen and (c) IL-4 measured in the spleen. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, AA = rhSP-A treated sensitized mice.

Fig. 3

Cytokines measured 1 day after treatment with two daily doses of 10 µg rfhSP-D given intranasally after intranasal challenge with Afu 1wcf. (a) IL-12 measured in the spleen, (b) IFN-γ measured in the spleen and (c) IL-4 measured in the spleen. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, AA = rhSP-A treated sensitized mice.

Fig. 3

Cytokines measured 1 day after treatment with two daily doses of 10 µg rfhSP-D given intranasally after intranasal challenge with Afu 1wcf. (a) IL-12 measured in the spleen, (b) IFN-γ measured in the spleen and (c) IL-4 measured in the spleen. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, AA = rhSP-A treated sensitized mice.

Fig. 4

Mice were treated with four daily doses of 10 µg rfhSP-D given intranasally after intranasal challenge with Afu 1wcf. Plethysmography was measured 2 h after an intranasal re-challenge with Afu 1wcf alone given 3 days after completion of treatment. (a) Dose–response to increasing doses of methacholine. ♦, P; ▪, AP; ▴, AR. (b) Response to 30 mg/ml methacholine after treatment with four daily doses of 10 µg rfhSP-D or rhSP-A given intranasally after intranasal challenge with Afu 1wcf. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, AA = rfhSP-A-treated sensitized mice.

Fig. 4

Mice were treated with four daily doses of 10 µg rfhSP-D given intranasally after intranasal challenge with Afu 1wcf. Plethysmography was measured 2 h after an intranasal re-challenge with Afu 1wcf alone given 3 days after completion of treatment. (a) Dose–response to increasing doses of methacholine. ♦, P; ▪, AP; ▴, AR. (b) Response to 30 mg/ml methacholine after treatment with four daily doses of 10 µg rfhSP-D or rhSP-A given intranasally after intranasal challenge with Afu 1wcf. P = PBS-treated non-sensitized mice, AP = PBS-treated sensitized mice, AR = rfhSP-D-treated sensitized mice, AA = rfhSP-A-treated sensitized mice.