Regulation of inflammation and bacterial clearance by lung collectins.

Pulmonary surfactant proteins (SP) A and D play important roles in the innate immune system of the lung. These proteins belong to the collectin subgroup in which lectin domains are associated with collagenous structures. To obtain a better understanding of how lung collectins modulate cellular responses, the authors investigated whether SP-A interacts with the toll-like receptor 2 (TLR2).

Direct binding of Toll-like receptor 2 to zymosan, and zymosan-induced NF-kappa B activation and TNF-alpha secretion are down-regulated by lung collectin surfactant protein A.

The lung collectin surfactant protein A (SP-A) has been implicated in the regulation of pulmonary host defense and inflammation. Zymosan induces proinflammatory cytokines in immune cells. Toll-like receptor (TLR)2 has been shown to be involved in zymosan-induced signaling.