Interaction of human lung surfactant proteins A and D with mite (Dermatophagoides pteronyssinus) allergens.
Human lung surfactant proteins A (SP-A) and D (SP-D) are both collagenous C-type lectins which appear to mediate antimicrobial activity by binding to carbohydrates on micro-organisms and to receptors on phagocytic cells. Purified native SP-A and SP-D, isolated from human bronchoalveolar lavage fluid, were found to bind to whole mite extracts (Dermatophagoides pteronyssinus) and the purified allergen Der p I, in a carbohydrate-specific and calcium-dependent manner. Binding was inhibited by ethylenediamine tetra-acetic acid (EDTA) as well as by maltose in the case of SP-D, or mannose in the case of SP-A. A recombinant polypeptide, which trimerized to form the neck region and carbohydrate recognition domains of SP-D, also inhibited the binding of native SP-D to the whole mite extract and Der p I. Both SP-A and SP-D did not bind to deglycosylated whole mite extracts or to recombinant Der p proteins, which lacked carbohydrate residues. These results suggest that the ability of surfactant proteins to bind certain allergens is mediated through their carbohydrate-recognition domains (CRDs) interacting with carbohydrate residues on the allergens. Moreover, SP-A and SP-D were found to inhibit allergen-specific IgE binding to the mite extracts either via steric hindrance or competitive binding. It is therefore possible that SP-A and SP-D may be involved in the modulation of allergen sensitization and/or the development of allergic reactions.
Wang
J Y
JY
Department of Biochemistry, University of Oxford, UK.
Kishore
U
U
Lim
B L
BL
Strong
P
P
Reid
K B
KB
D000485:Allergens / Q000378:metabolism*; D000818:Animals; D000941:Antigens / Q000378:metabolism; D039741:Antigens, Dermatophagoides; D001667:Binding, Competitive / Q000187:drug effects; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002118:Calcium / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D006023:Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008320:Maltose / Q000494:pharmacology; D008358:Mannose / Q000494:pharmacology; D008925:Mites / Q000378:metabolism*; D011510:Proteolipids / Q000302:isolation & purification / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins
D000485:Allergens; D000941:Antigens; D039741:Antigens, Dermatophagoides; D002352:Carrier Proteins; D006023:Glycoproteins; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D011994:Recombinant Proteins; D008320:Maltose; D004492:Edetic Acid; D008358:Mannose; D002118:Calcium