Accumulation of surfactant protein D in human pulmonary alveolar proteinosis

Am J Pathol. 1993 Jan;142(1):241-8.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / chemistry
  • Bronchoalveolar Lavage Fluid
  • Cross Reactions
  • Enzyme-Linked Immunosorbent Assay
  • Glycoproteins / chemistry
  • Glycoproteins / isolation & purification
  • Glycoproteins / metabolism*
  • Humans
  • Macromolecular Substances
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Pulmonary Alveolar Proteinosis / metabolism*
  • Pulmonary Alveolar Proteinosis / pathology
  • Pulmonary Surfactant-Associated Protein D
  • Pulmonary Surfactants / chemistry
  • Pulmonary Surfactants / isolation & purification
  • Pulmonary Surfactants / metabolism*
  • Rats
  • Sequence Homology, Amino Acid


  • Antibodies, Monoclonal
  • Glycoproteins
  • Macromolecular Substances
  • Pulmonary Surfactant-Associated Protein D
  • Pulmonary Surfactants