Protein patterns of human nasal and bronchoalveolar lavage fluids analyzed with two‐dimensional gel electrophoresis

Abstract

We have previously described the protein patterns of human nasal lavage fluid (NLF) and bronchoalveolar lavage fluid (BALF) after two-dimensional gel electrophoresis (2-DE). We now report the identification of a number of additional proteins in these 2-DE patterns. Several plasma proteins (α₂-macroglobulin, haptoglobin α₁-chain, IgA S chain, ceruloplasmin, α₁-microglobulin, amyloid P and apolipoprotein A-1) could be included both in the BALF and NLF spot pattern data bases by matching with a master plasma 2-DE pattern (SWISS-2DPAGE). Furthermore, lysozyme, lactoferrin and the antiinflammatory proteins lipocortin-1 and Clara cell protein 16 (CC-16) were identified by matching with reference proteins and Western immunoblots. Significant differences in the levels of some of the identified proteins were found between NLF and BALF, and between BALF from smokers and nonsmokers. Transferrin, hemopexin and haptoglobin α₁ were lower in NLF than BALF, while IgA, lysozyme and lactoferrin were higher in NLF than BALF. One form of α₁-microglobulin was more abundant in NLF than in BALF, while the opposite was found for a second form of the same protein. Moreover, the levels of IgA, ceruloplasmin and the pro-form of apolipoprotein A-1 in BALF were lower in smokers than in nonsmokers. The possibility to describe and analyze differences in NLF and BALF 2-DE patterns at the protein spot level may have wide clinical applications.