title: Antibacterial peptides in bronchoalveolar lavage fluid.
abstract: Defensins and other antimicrobial peptides act in the innate host defense of epithelial surfaces. Human beta defensin 1 (hBD-1) has recently been shown to be expressed in airway epithelial cells and so has been implicated as a primary component of antibacterial activity in human lung. We attempted to purify these molecules from bronchoalveolar lavage fluid (BALF). Extraction of BALF on SepPak C-18 cartridges, followed by continuous acid-urea polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography yielded one fraction with antibacterial activity associated with factors of < 6.5 kD. N-terminal amino acid sequencing identified these peptides as human neutrophil defensins (HD) 1 through 3. No hBD-1 was detected. Together with lysozyme, it appears that HD-1 through -3 are the most prominent antimicrobial factors in BALF. The contribution of epithelial defensins such as hBD-1 to antibacterial defense of human airway in vivo remains to be elucidated.
authors.affiliation: Paediatric Molecular Genetics, Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: Schnapp
authors.forename: A
authors.initials: A
authors.lastname: Harris
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D023082:Defensins; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008837:Micrococcus / Q000187:drug effects; D009113:Muramidase / Q000032:analysis; D009504:Neutrophils / Q000737:chemistry; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D023083:beta-Defensins
chemical_list: D000900:Anti-Bacterial Agents; D001798:Blood Proteins; C406407:DEFB1 protein, human; D023082:Defensins; D023083:beta-Defensins; D009113:Muramidase