PLUNC (palate, lung and nasal epithelial clone) is a newly discovered gene that is expressed in the upper respiratory tract and is suggested to be of importance in host defence against bacteria. We have identified two forms of the PLUNC protein in human nasal lavage fluid (NLF) using two-dimensional gel electrophoresis (2-DE) and MS. The apparent molecular masses and isoelectric points of these forms are 24.8 kDa/pI 5.4 and 25.1 kDa/pI 5.5. Notably, the 24.8 kDa/pI 5.4 form of PLUNC is an abundant protein in the 2-DE protein patterns of NLF from healthy subjects. Decreased levels of PLUNC were found in NLF from smokers and workers exposed to reactive epoxy chemicals, indicating that long-term exposure to airway irritants impairs the production of PLUNC in the upper respiratory tract. We have also investigated the presence of lipopolysaccharide (LPS)-binding proteins in NLF. Five proteins were found to adsorb to a LPS-coated surface; two of these proteins correspond to the two PLUNC forms, as judged by 2-DE pattern matching. For comparison, human saliva was found to contain a set of LPS-binding proteins with similar 2-DE spot positions (the same pIs but somewhat lower apparent molecular masses of ≈20 kDa). These results indicate that PLUNC may be a new marker of airway inflammation and may play a part in the innate immune response, and that human saliva contains yet other members of the family of LPS-binding proteins.
- epoxy chemical
- mass spectrometry
- nasal lavage fluid
- PLUNC (palate
- lung and nasal epithelial clone)
- two-dimensional gel electrophoresis
BPI-Like Proteins in Oral and Airway Epithelia a meeting held at Holiday Inn, Ventura, California, U.S.A., 7 February 2003
Abbreviations used: 2-DE, two-dimensional gel electrophoresis; DMBA, dimethylbenzylamine; LPS, lipopolysaccharide; MALDI-TOF, matrix-assisted laser-desorption ionization–time-of-flight; NLF, nasal lavage fluid; OAA, organic acid anhydrides; PLUNC, palate, lung and nasal epithelial clone.
- © 2003 Biochemical Society