Table 1.

SLPI and elafin characteristics

Property	SLPI	ESI/elafin/SKALP
Family name	Four disulfide core	Four disulfide core/trappin
Molecular mass (kDa)	11.7	9.8
Spectrum of protease inhibition	HNE, trypsin, chymotrypsin, tryptase,	HNE, pig pancreatic elastase, proteinase-3
	chymase, cathepsin G
Cell and tissue distribution in lung	Tracheal, bronchial, Clara, alveolar type II cells,	Tracheal, Clara, alveolar type II cells,
	monocytes, alveolar macrophages, neutrophils	alveolar macrophages
Regulatory stimuli	LPS, IL-1, TNF, HNE	IL-1, TNF, HNE
Biological properties	Antimicrobial, antiviral, anti-HNE, inhibition of	Antimicrobial, anti-HNE
	monocyte inflammatory potential
Gene therapy potential	Currently being explored	Adenovirus-elafin protects against lung injury
		(rodent model)

HNE = neutrophil elastase.