Partially Opened Triple Helix is the Biologically Active Conformation of 1→3-β-Glucans that Induces Pulmonary Inflammation in Rats

1 M 3- g -Glucans produce pulmonary inflammation in rats and are commonly found in indoor air dust samples. Conformation is an important factor determining the biological activity of 1 M 3- g -glucans. The partially opened triple-helix conformation induced by NaOH treatment and the annealed triple-helix conformation have been identified by fluorescence resonance energy transfer spectroscopy in our previous study. The objective of this study was to examine the role of these conformations of 1 M 3- g -glucans in the induction of pulmonary inflammation in rats. A partially opened triple-helix conformation of the known inflammatory 1 M 3- g -glucan zymosan was prepared by treating zymosan with NaOH followed by neutralization and dialysis. The annealed triple-helix conformation was prepared by allowing the partially opened triple-helix conformation to anneal for 9 d at room temperature. Rats were exposed to fresh or annealed NaOH-treated zymosan via intratracheal instillation. The results show that the zymosan...