The outer membranes of certain bacteria contain lipopolysaccharide (LPS). This is a glycolipid that can induce the host's immune system to produce cytokines, which, if left unchecked, can lead to septic shock and death. The human receptor for LPS has now been identified as a protein called Toll-like receptor 2, and theDrosophilahomologue of this protein is already known to be involved in defence against fungal infections.