title: Accumulation of surfactant protein D in human pulmonary alveolar proteinosis.
abstract: Surfactant protein D (SP-D) is a collagenous calcium-dependent carbohydrate-binding protein that is structurally related to the serum mannose-binding proteins and pulmonary surfactant protein A. SP-D was initially characterized as a biosynthetic product of freshly isolated rat type II cells and first purified in chemical amounts from bronchoalveolar lavage of rats with silica-induced alveolar lipoproteinosis. The present studies describe the characterization of human SP-D isolated from therapeutic bronchoalveolar lavage of patients with pulmonary alveolar proteinosis. Human proteinosis SP-D was extracted from the 10,000 x g pellet of bronchoalveolar lavage with 100 mmol/L glucose or ethylenediamine tetraacetic acid, and specifically bound to and eluted from maltosyl-agarose. The protein cross-reacted with monospecific antibodies to rat SP-D by enzyme-linked immunosorbent assay and immunoblot and eluted near the position of rat SP-D on reverse-phase high performance liquid chromatography. When chromatographed on 4% agarose (A-15M) in the presence of ethylenediamine tetraacetic acid, the solubilized human proteinosis SP-D eluted near the void volume and earlier than rat SP-D dodecamers or human SP-D multimers in the lavage supernatant. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of proteins in the lavage pellet with antibodies to the carbohydrate-binding domain of proteinosis human SP-D demonstrated covalently cross-linked multimers of SP-D monomers (43 kd, reduced) and multimers of trimeric components stabilized by disulfide and non-disulfide bonds. These studies describe the isolation and biochemical characterization of human SP-D and demonstrate the abnormal accumulation of this protein in the air spaces of patients with alveolar proteinosis.
authors.affiliation: Department of Pathology, Jewish Hospital, St. Louis, MO 63110.
authors.forename: E
authors.initials: E
authors.lastname: Crouch
authors.forename: A
authors.initials: A
authors.lastname: Persson
authors.forename: D
authors.initials: D
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001992:Bronchoalveolar Lavage Fluid; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011649:Pulmonary Alveolar Proteinosis / Q000378:metabolism* / Q000473:pathology; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D046911:Macromolecular Substances; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants