Protective role of a recombinant fragment of human surfactant protein D (SP-D) against pulmonary hypersensitivity in a murine model of dust mite allergy

VOLUME 111, NUMBER 2 23 Protective Role of a Recombinant Fragment of Human Surfacrant Protein D (SP-D) Against Pulmonary Hypersensitivity in a Murine Model of Dust Mite Allergy M. K. Singh], T. M. Gupta l, B. C. Urban 2, U. P. Sarma I, U. Kishore2; t Molecular Biochemistry and Diagnostics, Centre for Biochemical Technology, Delhi, INDIA, 2Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UNITED KINGDOM. RATIONALE: A recombinant fragment of human lung surfactant protein D (SP-D), containing homotrimeric neck and CRD regions (rhSP-D), has been shown to bind allergens derived from house dust mite (Dermatophagoides pteronyssinus), inhibit the ability of specific IgE from mite-sensitive patients to bind these allergens, and block subsequent histamine release from sensitized basophils. In the present study, we have examined the therapeutic effect of intranasal administration of a range of concentrations of rhSP-D in a mnrine model of pulmonary hypersensitivity induced by mite allergens. METHODS: Murine model of pulmonary hypersensitivity induced by mite allergens was developed by repeated intranasal and intraperitoneal administration of mite allergenic extract. Effect of different doses of rhSPD on levels of specific IgE and cytokines (IL-2, II-4, IL-5 and IFNT) and pulmonary and peripheral eosinophilia were examined. RESULTS: The murine model of pulmonary hypersensitivity induced by mite allergens exhibited high levels of specific IgE, peripheral blood and pulmonary eosinophilia and a Th2 cytokine profile. Treatment with rhSPD lowered eosinophilia and IgE levels, and lung sections of the murine model showed considerably reduced infiltration of lymphocytes and eosinophils. The levels of IL-2, IL-4 and IL-5 were decreased, while that of IFN7 was raised in the spleen cell culture supernatant of treated mice, indicating a marked shift from Th2 to Thl type cytokine response. CONCLUSIONS: These results strongly support the possibility of using exogenous rhSP-D as therapy for mite induced pulmonary hypersensitivity and allergies. Funding: Weatherall Institute of Molecular Medicine 524 NK Cell-Dependent, Airway-Specific, Innate Eosinophilic Response to Alternaria in Mice K. Iijima, T. Kobayashi, H. Kita; Mayo Clinic, Rochester, MN. RATIONALE: Because allergy to fungal proteins is implicated in certain types of human asthma, we characterized the immune response to fungi using mouse models. METHODS: Mice were sensitized intraperitoneally with fungal extracts; naive and sensitized mice were challenged intranasally with the same extracts. Bronchoalveolar lavage fluids were collected and analyzed for airway inflammation. RESULTS: Sensitization and challenge of mice with fungal extracts induced airway eosinophilia and hyperreactivity. Surprisingly, marked airway eosinophilia was also observed in naive (not sensitized intraperitoneally) mice challenged with Alternaria antigens. This "innate eosinophilic response" to fungi was specific to Alternaria because other fungi, such as Aspergillus and Candida, did not provoke a similar response. Systemic administration of anti-lL-5 antibody inhibited this eosinophilia. Specific IgE antibody to Alternaria was absent. Furthermore, airway production of IL-5 was observed as early as 4 hours after challenge of naive mice to Alternaria. Importantly. this airway eosinophilic response was observed in T-cell deficient mice, including nude, SCID, and Raglknockout mice, but was strongly suppressed in mice treated with an antibody to NK cells (clone DX5). Finally, Alternaria extracts induced IL-5 production in organ culture of lungs, but not spleen, from naive mice. CONCLUSIONS: Naive mice react to Alternaria antigens with an airway IL-5 response and eosinophilia likely through an NK cell-dependent, innate immune mechanism. This fungus-induced airway eosinophilia may explain certain types of human asthma that lack apparent IgE antibodies to allergens. Funding: NIH 525 A Causative Relationship Exists Between tosinophils and the Development of Allergic Pulmonary Pathologies N.A. Lee l, H. H. Shen I, 2, J. R. Crosby I , E. M. Hines t, M. T. Borchers 3, M. P. McGarry 3, S. I. Ochkur 3, T. L. Biechele j, K. R. O'Neill I, T. L. Ansay 1, D. C. Colbert 3, S. A. Cormier 3, J. P. Justice 1, J. J. Lee3; IDepartment of Biochemistry and Molecular Biology, Division of Hematology/Oncology, Mayo Clinic Scottsdale, Scottsdale, AZ, 2Respiratory Medicine, Zhejiang University College of Medicine, Hangzhou, CHINA, 3Department of Biochemistry and Molecular Biology, Division of Pulmonary Medicine, Mayo Clinic Scottsdale, Scottsdale, AZ. RATIONALE: Allergic asthma and mouse models of allergic respiratory inflammation are invariably associated with the accumulation of pulmonary eosinophils, however, this association has remained correlative. In this report, a causative relationship between eosinophils and allergenmediated pathologies was established using an eosinophil adoptive transfer strategy. METHODS AND RESULTS: Eosinophils were isolated from IL-5 transgenic mice and transferred (IT) into the lungs of either naive or OVAtreated IL-5 -/animals. This strategy resulted in a pulmonary eosinophilia equivalent to that observed in OVA-treated wild-type mice. Concomitant consequence of this eosinophil transfer was to restored airway mucus in OVA-treated IL-5/mice to OVA-treated wild type levels. Moreover, the transfer also resulted in the development of AHR. Significantly, these pulmonary changes did not occur when eosinophils were transferred into naive IL-5 -/mice, eliminating non-specific consequences of the eosinophil transfer as a possible explanation. In addition, administration of TRFK-5 (anti-(IL-5)) antibody had no effect on the development of eosinophil-mediated pathologies, showing that these pathologies did not arise because of IL-5 expression by the transferred eosinophils. In contrast, administration of OVA-treated IL-5 -/mice with GKI.5 (anti-CD4) antibodies abolished the increases in mucus accumulation and AHR following transfer of eosinophils. CONCLUSIONS: CD4 § T cell-mediated inflammatory signals as well as eosinophils are each necessary, yet alone insuMcient, for the development of allergic pulmonary pathology. These data support an expanded view of T cell and eosinophil activities in the lung and suggest that eosinophil effector functions impinge directly on lung function. Funding: Mayo Foundation, NIH, and American Lung Association