Aberrant processing of surfactant protein C in hereditary SP-B deficiency

Am J Physiol. 1995 Apr;268(4 Pt 1):L647-56. doi: 10.1152/ajplung.1995.268.4.L647.


Hereditary surfactant protein B (SP-B) deficiency causes lethal neonatal respiratory disease associated with abnormalities in pulmonary surfactant proteins and lipids. SP-C, a 4-kDa hydrophobic protein produced from a 21-kDa precursor, cooperates with SP-B to enhance the surface active properties of surfactant phospholipids. Anti-proSP-C polyclonal antisera were produced against fusion proteins containing 1) the amino terminus (amino acids 1-20), 2) the region carboxy-terminal to the mature SP-C peptide (amino acids 58-77), and 3) full-length 197-amino acid proSP-C and were characterized using immunoprecipitation, Western blot, and immunohistochemical techniques. Western blot analysis of bronchoalveolar lavage and amniotic fluid from hereditary SP-B-deficient patients allowed identification of a 12-kDa form of SP-C that contained epitopes consistent with the amino-terminal and active peptide regions of SP-C (amino acids 1-57). The 12-kDa SP-C peptide was not detected in bronchoalveolar lavage from healthy adults or adults with alveolar proteinosis or pneumonia. We conclude that SP-B deficiency is associated with the aberrant processing and secretion of an immature SP-C peptide, which may contribute to the respiratory failure associated with hereditary SP-B deficiency.

Publication types

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

MeSH terms

  • Adult
  • Amniotic Fluid / chemistry
  • Bronchoalveolar Lavage Fluid / chemistry
  • Epitopes
  • Humans
  • Immune Sera
  • Infant, Newborn
  • Molecular Weight
  • Peptide Fragments / analysis
  • Protein Precursors / immunology
  • Protein Processing, Post-Translational*
  • Proteolipids / chemistry
  • Proteolipids / genetics*
  • Proteolipids / immunology
  • Proteolipids / metabolism*
  • Pulmonary Surfactants / chemistry
  • Pulmonary Surfactants / deficiency*
  • Pulmonary Surfactants / genetics*
  • Pulmonary Surfactants / immunology
  • Pulmonary Surfactants / metabolism
  • Reference Values


  • Epitopes
  • Immune Sera
  • Peptide Fragments
  • Protein Precursors
  • Proteolipids
  • Pulmonary Surfactants