Biomedical Engineering Reference
In-Depth Information
characterized of the WAP family of proteins, which currently stands at 15
members, and are situated in a tight cluster on chromosome 20ql2-13 (41).
Expression sites for SLPI are found primarily in mucosal tissue, but can
also be made by inflammatory cells including macrophages and neutro-
phils (42,43). Secretory leukoprotease inhibitor has been shown to inhibit
NE, cathepsin G, chymotrypsin, and trypsin (40). Interestingly, SLPI does
not inhibit the other neutrophil serine protease, proteinase 3, in contrast to
AAT and elafin (44). Owing to its high association rate constant for NE,
SLPI was considered to be the major inhibitor of NE in the upper respira-
tory tract. Recent research has shown that SLPI possesses antibacterial
properties, which may be important in front-line defense of the upper
airways. However, it is the work describing SLPI as an anti-inflammatory
=
immunomodulatory protein that has gathered most attention in the recent
past (Fig. 2).
Figure 2
Schematic describing the multifunctional role of SLPI. Extracellularly,
SLPI inhibits NE activity, inhibits bacterial growth, and is itself susceptible to
cleavage by elastolytic cathepsins. Secretory leukoprotease inhibitor also prevents
intracellular HIV replication and LPS-induced NF-
k
B activation in monocytes.
