Modulation of innate and adaptive immune responses by arabinoxylans

Humans are exposed to harmful pathogens and a wide range of noxious substances every day. The immune system reacts to, and destroys, these pathogens and harmful substances. The immune system is composed of innate and adaptive immunity, which liaise to protect the host and maintain health. Foods, especially cereals, have been reported to modulate the immune response. Arabinoxylans are nonstarch polysaccharides that have been shown to possess immune-modulatory activities. This review article discusses the fundamentals of the immune system and provides an overview of the immunomodulatory potential of arabinoxylans in conjunction with their structural characteristics and proposed similarities with lipopolysaccharides. Practical applications: Understanding how the immune system works is of vital importance to prevent unnecessary or excessive inflammatory responses. Consumption of arabinoxylans has been shown to possess immunomodulatory potential. However, their mechanism of action has not been elucidated. Arabinoxylans share some similarities with lipopolysaccharides (LPS), a molecule that induces substantial and sometimes excessive immune responses such as fever following infection by pathogens. Thus, we propose that arabinoxylans might possibly act on the same receptor as LPS. Competition between dietary-derived arabinoxylans and LPS at a shared receptor would then have the potential to inhibit or attenuate excessive LPS-induced inflammatory responses that are typical of infection/fever. In the absence of infection and consequently no competition at the LPS receptor, consumption of dietary arabinoxylans may protect against the risk of infection by moderately activating the receptor and heightening natural (background) levels of immunity.