BPIFA1, also known as PLUNC, belongs to the short subfamily of PLUNC family proteins and have homology only to the Nterminal domains of BPI. It is a secreted protein that is expressed in the secretory ducts and submucosal glands of tracheobronchial tissues. BPIFA1 binds to lipopolysaccharide (LPS) in nasal lavage fluid (NLF) which points to its role in the inflammatory response of the upper airways after exposure to irritants. Decreased levels of BPIFA1 occur in the NLF of smokers and people who have been exposed to reactive epoxy chemicals, indicating that long-term exposure to airway irritants impairs the production of BPIFA1 in the upper respiratory tract. Recombinant human BPIFA1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.