Figure 2.

Airway innate immunity. (a) The major pattern recognition receptor (PRR) is the Toll-like receptor (TLR) family which interact with microbial-derived factors or pathogen-associated molecular patterns (PAMPs) such as LPS from P. aeruginosa. LPS-induced activation of TLR induces an IL-8 response via a NF-κB pathway. (b) Important antiproteases and antimicrobial proteins in the lung include AAT, SLPI, elafin, the cathelicidin LL-37, lactoferrin, and the human beta defensins (HBDs); these can be cleaved and inactivated by neutrophil elastase in the CF lung. CBM: capillary basement membrane.