Effect of glucan on murine lupus evolution and on host resistance to Klebsiella pneumoniae.

Glucan is a polysaccharide from the yeast Saccharomyces cerevisiae that stimulates the mononuclear phagocytic system (MPS). NZB/NZW F1 mice were divided into two groups: one group received a subcutaneous injection of 0.5 mg glucan/animal for 1 week, and the other received the same dose for 3 months. No changes were observed in those animals submitted to short-term glucan treatment, whereas animals with active lupus and submitted to long-term glucan administration presented early death, with significant differences in accumulated mortality rates over 33-37 weeks, when compared to controls. No deaths were observed in lupus mice treated with glucan 24 hours before the induction of septic shock by Klebsiella pneumoniae, in contrast to mortality of 95.3% in the control group during the follow-up period of 12 days. We conclude that although glucan is able to exacerbate lupus activity, it enhances resistance to infection in lupus mice.