Biological response modifiers (BRMs) are substances which augment immune response. BRMs can be cytokines which are produced endogenously in our body by immune cells or derivatives of bacteria, fungi, brown algae, Aloe vera and photosynthetic plants. Such exogenous derivatives (exogenous BRMs) can be nucleic acid (CpG), lipid (lipotechoic acid), protein or polysaccharide in nature. The receptors for these exogenous BRMs are pattern recognition receptors. The binding of exogenous BRMs to pattern recognition receptors triggers immune response. Exogenous BRMs have been reported to have anti-viral, anti-bacterial, anti-fungal, anti-parasitic, and anti-tumour activities. Among different exogenous BRMs, polysaccharide BRMs have the widest occurrence in nature. The sources of polysaccharide BRMs are very diverse. The polysaccharides can be originated from bacteria, fungi, brown algae and photosynthetic plants. At cellular level, the polysaccharide derivatives represent either the reserve polysaccharides in cytoplasm, or structural polysaccharides on membrane or cell wall of the organisms.

Thanks Dr.Anirban Roy. Thanks for your brief out on polysaccharides as BRM's.. What will be their scope in development as leads with special reference to its bioavailability? 

Usually they are not adsorbed as is.

Role in drug discovery???? Challeging: first of all their chemical structure is not Always described