Immunological functions of steryl glycosides

Steryl glycosides, sterols glycosylated at the 3β-hydroxy group, have been widely found in plants, algae, and fungi, but are rare in bacteria and animals. Glycosylation of sterols is known to modify properties of the cell membrane and confer resistance against stresses by freezing or heat-shock on cells. Furthermore, accumulating evidence obtained from recent research suggests important biological functions of steryl glycosides, including regulation of host defenses against pathogens, lipid metabolism, and developmental events. This review is focused on the immunological functions of steryl glycosides, such as modulation of host immune functions upon exposure to cholesteryl glycosides produced by pathogenic bacteria.