Interaction of human lung surfactant proteins A and D with mite (Dermatophagoides pteronyssinus) allergens

• Published in: Clinical and experimental immunology 1996-11, Vol.106 (2), p.367-373
• Main Authors: WANG, J. Y., KISHORE, U., LIM, B. L., STRONG, P., REID, K. B. M.
• Format: Article
• Language: English
• Subjects: Allergens - metabolism; Animals; Antigens - metabolism; Antigens, allergens; Antigens, Dermatophagoides; Binding, Competitive - drug effects; Biological and medical sciences; Bronchoalveolar Lavage Fluid - chemistry; Calcium - pharmacology; Carrier Proteins - metabolism; Dermatophagoides pteronyssinus; Edetic Acid - pharmacology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Glycoproteins - isolation & purification; Glycoproteins - metabolism; Humans; IgE; Immediate hypersensitivity. Allergy. Anaphylaxis, etc; Immunobiology; Maltose - pharmacology; Mannose - pharmacology; mite allergen; Mites - metabolism; Original; Proteolipids - isolation & purification; Proteolipids - metabolism; Pulmonary Surfactant-Associated Protein A; Pulmonary Surfactant-Associated Protein D; Pulmonary Surfactant-Associated Proteins; Pulmonary Surfactants - isolation & purification; Pulmonary Surfactants - metabolism; Recombinant Proteins; surfactant protein A; surfactant protein D
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1046/j.1365-2249.1996.d01-838.x

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.