Demonstration of different forms of the anti-inflammatory proteins lipocortin-1 and Clara cell protein-16 in human nasal and bronchoalveolar lavage fluids.

Abstract

The anti-inflammatory proteins lipocortin-1 and Clara cell protein-16 (CC-16) were studied in two-dimensional gel electrophoresis (2-DE) protein patterns of human nasal lavage fluids (NLFs) and bronchoalveolar lavage fluids (BALFs). Seven forms of lipocortin-1 were detected with Western immunoblots: three isoforms with an apparently normal Mr of 38 kDa and pI of 5.9, 6.0 and 6.1, and four truncated variants with pI/kDa 6.0/36, 6.4/36, 7.0/33, and 7.4/34. Four 6 kDa isoforms of CC-16 were found with pI 4.6, 4.8, 4.9, and 5.2. Lipocortin-1 and CC-16 were expressed in all individuals tested although not all variants were found in each individual. The overall levels of lipocortin-1 were higher in BALF than NLF and there were significant differences in the distribution of the different lipocortin-1 forms between BALFs and NLFs. One patient with occupational asthma and four children with rhinitis had increased levels of one of the truncated lipocortin-1 forms in NLF (pI/kDa: 7.4/34) and decreased levels of the major CC-16 form (pI/kDa: 4.8/6). The levels of CC-16 but not of lipocortin-1 were higher in BALF from smokers than from nonsmokers. These results indicate that the levels of lipocortin-1 and CC-16 in NLF and BALF may be altered in inflammatory airway disorders. Furthermore, the identification of different forms of the two proteins makes possible more detailed studies on the role of these proteins in inflammatory disease processes and anti-inflammatory therapies.