Proteomic analysis of human bronchoalveolar lavage fluid: expression profiling of surfactant-associated protein A isomers derived from human pulmonary alveolar proteinosis using immunoaffinity detection.Proteomics. 2003 Jan; 3(1):87-94.P
Human bronchoalveolar lavage fluid (BALF) proteins from pulmonary alveolar proteinosis (PAP) obtained by washing the epithelial lining of the lung with phosphate-buffered saline, were separated using high resolution two-dimensional gel electrophoresis (2-DE) under denaturing and reducing conditions. By Western blotting, the proteins were transferred from polyacrylamide gel onto a chemical resilient membrane. The surfactant-associated protein A (SP-A) isomers were then identified with enhanced chemiluminescence detection (ECL) using antibody-antigen reaction. Some of the gels were treated with silver staining after 2-DE. The molecular masses of SP-A isomers in BALF from PAP ranged from 20.5 to 26, 26 to 32, and 32 to 42 kDa, respectively; and isoelectric points (pI) were in pH range of 4.5-5.4 under denaturing and reducing conditions. In the mass range of 20.5-26 kDa and pI of 4.5-5.4, there were five isomers, and in mass range of 26-32 kDa and pI of 4.5 to 5.4, there were at least eight isomers on the ECL detection film. However, in the mass range of 32-42 kDa and pI of 4.5-5.4, there were three isomers separated one from another but there was also a cluster of overlapping spots on the ECL detection film. Thus, this communication describes a characteristic 2-DE pattern of SP-A isomers in BALF from PAP as follows. (1) The five isomers of mass 20.5-26 kDa and pI of 4.5-5.4; (2) the eight isomers of mass 26-32 kDa and pI of 4.5-5.4; and (3) the three isomers of mass 32-42 kDa and pI of 4.5-5.4.